The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
Estimated average burden
hours per response: 23.8
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
3-D SYS CORP DEL COM NEW COM 88554D205 8,823 763,913 SH   SOLE   763,913 0 0
3M CO COM COM 88579Y101 613 4,325 SH   SOLE   4,325 0 0
AAC HLDGS INC COM COM 000307108 18,594 835,706 SH   SOLE   835,706 0 0
ABBOTT LABS COM COM 002824100 467 11,622 SH   SOLE   11,622 0 0
ABBVIE INC COM COM 00287Y109 482 8,855 SH   SOLE   8,855 0 0
ALPHABET INC- CL C COM 02079k107 61,181 100,557 SH   SOLE   100,557 0 0
ALTERA CORP COM COM 021441100 351 7,018 SH   SOLE   7,018 0 0
AMAZON COM INC COM COM 023135106 424 829 SH   SOLE   829 0 0
AMBER RD INC COM COM 02318Y108 74 17,595 SH   SOLE   17,595 0 0
AMERICAN TOWER CORP NEW COM COM 03027X100 73,683 837,502 SH   SOLE   837,502 0 0
AMGEN INC COM COM 031162100 352 2,543 SH   SOLE   2,543 0 0
ANADARKO PETE CORP COM COM 032511107 320 5,300 SH   SOLE   5,300 0 0
ANSYS INC COM COM 03662Q105 166,800 1,892,439 SH   SOLE   1,892,439 0 0
APPLE INC COM COM 037833100 1,452 13,162 SH   SOLE   13,162 0 0
APPLIED MINERALS INC COM COM 03823M100 26 101,300 SH   SOLE   101,300 0 0
ATRION CORP COM COM 049904105 3,880 10,347 SH   SOLE   10,347 0 0
AUTOMATIC DATA PROCESSING INC COM 053015103 2,050 25,506 SH   SOLE   25,506 0 0
BECTON DICKINSON & CO COM COM 075887109 226 1,706 SH   SOLE   1,706 0 0
BERKLEY W R CORP COM COM 084423102 2,878 52,928 SH   SOLE   52,928 0 0
BERKSHIRE HATHAWAY INC DEL CL COM 084670108 1,367 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAY INC DEL CL COM 084670702 3,025 23,195 SH   SOLE   23,195 0 0
BIO TECHNE CORP COM COM 09073M104 18,246 197,340 SH   SOLE   197,340 0 0
BIOGEN INC COM COM 09062X103 59,384 203,501 SH   SOLE   203,501 0 0
BLACKBAUD INC COM COM 09227Q100 40,045 713,564 SH   SOLE   713,564 0 0
CAMPBELL SOUP CO COM COM 134429109 218 4,300 SH   SOLE   4,300 0 0
CANADIAN NATL RY CO COM COM 136375102 1,135 20,000 SH   SOLE   20,000 0 0
CAPITAL ONE FINL CORP COM COM 14040H105 1,880 25,917 SH   SOLE   25,917 0 0
CARE COMMUNITIES PROPERTIES COM 141624106 291 8,836 SH   SOLE   8,836 0 0
CARMAX INC COM COM 143130102 94,343 1,590,411 SH   SOLE   1,590,411 0 0
CELGENE CORP COM COM 151020104 71,394 660,016 SH   SOLE   660,016 0 0
CHEVRON CORP NEW COM COM 166764100 763 9,671 SH   SOLE   9,671 0 0
CHIPOTLE MEXICAN GRILL INC COM COM 169656105 46,984 65,233 SH   SOLE   65,233 0 0
CISCO SYS INC COM COM 17275R102 1,853 70,598 SH   SOLE   70,598 0 0
COCA COLA CO COM COM 191216100 1,135 28,300 SH   SOLE   28,300 0 0
COGNIZANT TECHNOLOGY SOLUTIONS COM 192446102 250 4,000 SH   SOLE   4,000 0 0
COLGATE PALMOLIVE CO COM COM 194162103 638 10,055 SH   SOLE   10,055 0 0
COMCAST CORP NEW CL A COM 20030N101 690 12,125 SH   SOLE   12,125 0 0
COMCAST CORP NEW CL A SPL COM 20030N200 3,470 60,622 SH   SOLE   60,622 0 0
CORE LABORATORIES N V COM COM N22717107 1,910 19,135 SH   SOLE   19,135 0 0
COSTAR GROUP INC COM COM 22160N109 72,049 416,322 SH   SOLE   416,322 0 0
CROWN CASTLE INTL CORP NEW COM COM 22822V101 5,417 68,678 SH   SOLE   68,678 0 0
DENTSPLY INTL INC NEW COM COM 249030107 238 4,700 SH   SOLE   4,700 0 0
DISCOVER FINL SVCS COM COM 254709108 72,635 1,397,088 SH   SOLE   1,397,088 0 0
DISNEY WALT CO COM DISNEY COM 254687106 979 9,579 SH   SOLE   9,579 0 0
DONALDSON INC COM COM 257651109 220 7,850 SH   SOLE   7,850 0 0
DOUGLAS DYNAMICS INC COM COM 25960R105 900 45,301 SH   SOLE   45,301 0 0
DU PONT E I DE NEMOURS & CO CO COM 263534109 241 5,007 SH   SOLE   5,007 0 0
DUKE REALTY CORP COM NEW COM 264411505 281 14,750 SH   SOLE   14,750 0 0
EAST WEST BANCORP INC COM COM 27579R104 327 8,500 SH   SOLE   8,500 0 0
ECOLAB INC COM COM 278865100 116,480 1,061,608 SH   SOLE   1,061,608 0 0
ELLIE MAE INC COM COM 28849P100 3,625 54,447 SH   SOLE   54,447 0 0
EMERSON ELEC CO COM COM 291011104 422 9,564 SH   SOLE   9,564 0 0
ENTERPRISE PRODS PARTNERS L P COM 293792107 458 18,400 SH   SOLE   18,400 0 0
ENVESTNET INC COM COM 29404K106 39,720 1,325,313 SH   SOLE   1,325,313 0 0
EQT CORP COM COM 26884L109 1,723 26,601 SH   SOLE   26,601 0 0
EQUITY RESIDENTIAL SH BEN INT COM 29476L107 532 7,076 SH   SOLE   7,076 0 0
EXACT SCIENCES CORP COM COM 30063P105 398 22,101 SH   SOLE   22,101 0 0
EXAMWORKS GROUP INC COM COM 30066A105 66,575 2,276,853 SH   SOLE   2,276,853 0 0
EXPEDITORS INTL WASH INC COM COM 302130109 573 12,172 SH   SOLE   12,172 0 0
EXPONENT INC COM COM 30214U102 37,955 851,778 SH   SOLE   851,778 0 0
EXPRESS SCRIPTS HLDG CO COM COM 30219G108 1,633 20,176 SH   SOLE   20,176 0 0
EXXON MOBIL CORP COM COM 30231G102 1,666 22,413 SH   SOLE   22,413 0 0
FASTENAL CO COM COM 311900104 96,483 2,635,427 SH   SOLE   2,635,427 0 0
FINANCIAL ENGINES INC COM COM 317485100 34,456 1,169,203 SH   SOLE   1,169,203 0 0
FISERV INC COM COM 337738108 5,757 66,468 SH   SOLE   66,468 0 0
FORTINET INC COM COM 34959E109 1,310 30,830 SH   SOLE   30,830 0 0
FREEPORT-MCMORAN INC CL B COM 35671D857 147 15,176 SH   SOLE   15,176 0 0
GENERAL ELECTRIC CO COM COM 369604103 3,171 125,722 SH   SOLE   125,722 0 0
GENUINE PARTS CO COM COM 372460105 409 4,934 SH   SOLE   4,934 0 0
GILEAD SCIENCES INC COM COM 375558103 753 7,667 SH   SOLE   7,667 0 0
GOOD TIMES RESTAURANTS INC COM COM 382140879 195 31,200 SH   SOLE   31,200 0 0
GOOGLE INC CL A COM 38259P508 299 469 SH   SOLE   469 0 0
GUIDEWIRE SOFTWARE INC COM COM 40171V100 409 7,777 SH   SOLE   7,777 0 0
HCP INC COM COM 40414L109 3,789 101,705 SH   SOLE   101,705 0 0
HEALTHCARE SVCS GRP INC COM COM 421906108 82,698 2,453,960 SH   SOLE   2,453,960 0 0
HOME DEPOT INC COM COM 437076102 369 3,197 SH   SOLE   3,197 0 0
HOVNANIAN ENTERPRISES INC CL A COM 442487203 27 15,000 SH   SOLE   15,000 0 0
IDEXX LABS INC COM COM 45168D104 8,771 118,128 SH   SOLE   118,128 0 0
ILLINOIS TOOL WKS INC COM COM 452308109 201 2,440 SH   SOLE   2,440 0 0
ILLUMINA INC COM COM 452327109 16,270 92,538 SH   SOLE   92,538 0 0
IMAX CORP COM COM 45245E109 113,646 3,363,297 SH   SOLE   3,363,297 0 0
INTEL CORP COM COM 458140100 12,624 418,849 SH   SOLE   418,849 0 0
INTERMAP TECHNOLOGIES CORP CL COM 458977204 10 25,000 SH   SOLE   25,000 0 0
INTERNATIONAL BUSINESS MACHS C COM 459200101 1,631 11,252 SH   SOLE   11,252 0 0
INTUITIVE SURGICAL INC COM NEW COM 46120E602 80,259 174,636 SH   SOLE   174,636 0 0
INVENTURE FOODS INC COM COM 461212102 288 32,440 SH   SOLE   32,440 0 0
JOHNSON & JOHNSON COM COM 478160104 9,657 103,445 SH   SOLE   103,445 0 0
JPMORGAN CHASE & CO COM COM 46625H100 336 5,514 SH   SOLE   5,514 0 0
KIMBERLY CLARK CORP COM COM 494368103 283 2,598 SH   SOLE   2,598 0 0
LABORATORY CORP AMER HLDGS COM COM 50540R409 1,991 18,353 SH   SOLE   18,353 0 0
LILLY ELI & CO COM COM 532457108 794 9,484 SH   SOLE   9,484 0 0
LINCOLN NATL CORP IND COM COM 534187109 263 5,536 SH   SOLE   5,536 0 0
LKQ CORP COM COM 501889208 149,005 5,254,067 SH   SOLE   5,254,067 0 0
LOWES COS INC COM COM 548661107 213 3,089 SH   SOLE   3,089 0 0
LYNAS CORPORATION LTD SHS COM Q5683J103 2 95,000 SH   SOLE   95,000 0 0
M & T BK CORP COM COM 55261F104 457 3,749 SH   SOLE   3,749 0 0
MACYS INC COM COM 55616P104 239 4,663 SH   SOLE   4,663 0 0
MAGELLAN MIDSTREAM PRTNRS LP C COM 559080106 216 3,600 SH   SOLE   3,600 0 0
MARKEL CORP COM COM 570535104 106,336 132,612 SH   SOLE   132,612 0 0
MASTERCARD INC CL A COM 57636Q104 55,043 610,778 SH   SOLE   610,778 0 0
MCBC HLDGS INC COM COM 55276F107 208 16,039 SH   SOLE   16,039 0 0
MCCORMICK & CO INC COM NON VTG COM 579780206 986 12,000 SH   SOLE   12,000 0 0
MCEWEN MNG INC COM COM 58039P107 24 28,000 SH   SOLE   28,000 0 0
MCGRAW HILL FINL INC COM COM 580645109 68,702 794,243 SH   SOLE   794,243 0 0
MERCK & CO INC NEW COM COM 58933Y105 1,160 23,487 SH   SOLE   23,487 0 0
MICROSOFT CORP COM COM 594918104 2,741 61,919 SH   SOLE   61,919 0 0
MIDDLEBY CORP COM COM 596278101 1,221 11,610 SH   SOLE   11,610 0 0
MONRO MUFFLER BRAKE INC COM COM 610236101 918 13,584 SH   SOLE   13,584 0 0
MOODYS CORP COM COM 615369105 122,134 1,243,732 SH   SOLE   1,243,732 0 0
NATIONAL AMERN UNIV HLDGS INC COM 63245Q105 56 20,000 SH   SOLE   20,000 0 0
NEOGEN CORP COM COM 640491106 441 9,800 SH   SOLE   9,800 0 0
O REILLY AUTOMOTIVE INC NEW CO COM 67103H107 17,810 71,239 SH   SOLE   71,239 0 0
ONEBEACON INSURANCE GROUP LTD COM G67742109 555 39,548 SH   SOLE   39,548 0 0
OXYSURE SYSTEMS INC COM COM 69208T101 3 10,000 SH   SOLE   10,000 0 0
PAYCHEX INC COM COM 704326107 2,963 62,200 SH   SOLE   62,200 0 0
PEPSICO INC COM COM 713448108 568 6,027 SH   SOLE   6,027 0 0
PERFORMANCE SPORTS GROUP LTD C COM 71377G100 545 40,616 SH   SOLE   40,616 0 0
PFIZER INC COM COM 717081103 1,030 32,795 SH   SOLE   32,795 0 0
PHILIP MORRIS INTL INC COM COM 718172109 430 5,418 SH   SOLE   5,418 0 0
PINNACLE WEST CAP CORP COM COM 723484101 318 4,956 SH   SOLE   4,956 0 0
PNC FINL SVCS GROUP INC COM COM 693475105 2,325 26,062 SH   SOLE   26,062 0 0
POOL CORPORATION COM COM 73278L105 230 3,188 SH   SOLE   3,188 0 0
POTASH CORP SASK INC COM COM 73755L107 20,630 1,003,880 SH   SOLE   1,003,880 0 0
PRA GROUP INC COM COM 69354N106 100,956 1,907,712 SH   SOLE   1,907,712 0 0
PRECISION CASTPARTS CORP COM COM 740189105 391 1,700 SH   SOLE   1,700 0 0
PRICE T ROWE GROUP INC COM COM 74144T108 11,552 166,219 SH   SOLE   166,219 0 0
PRICESMART INC COM COM 741511109 2,076 26,843 SH   SOLE   26,843 0 0
PROCTER & GAMBLE CO COM COM 742718109 16,793 233,432 SH   SOLE   233,432 0 0
QUALCOMM INC COM COM 747525103 42,597 792,804 SH   SOLE   792,804 0 0
QUALYS INC COM COM 74758T303 6,650 233,677 SH   SOLE   233,677 0 0
RANGE RES CORP COM COM 75281A109 26,118 813,148 SH   SOLE   813,148 0 0
RED HAT INC COM COM 756577102 139,322 1,938,256 SH   SOLE   1,938,256 0 0
ROPER TECHNOLOGIES INC COM 776696106 85,758 547,273 SH   SOLE   547,273 0 0
RUSH ENTERPRISES INC CL A COM 781846209 441 18,243 SH   SOLE   18,243 0 0
SBA COMMUNICATIONS CORP COM COM 78388J106 1,541 14,715 SH   SOLE   14,715 0 0
SCHLUMBERGER LTD COM COM 806857108 14,256 206,705 SH   SOLE   206,705 0 0
SEI INVESTMENTS CO COM COM 784117103 142,509 2,954,782 SH   SOLE   2,954,782 0 0
SIGNET JEWELERS LIMITED SHS COM G81276100 97,931 719,393 SH   SOLE   719,393 0 0
SILVER WHEATON CORP COM COM 828336107 198 16,500 SH   SOLE   16,500 0 0
SMITH & NEPHEW PLC SPDN ADR NE COM 83175M205 262 7,500 SH   SOLE   7,500 0 0
SOTHERLY HOTELS INC COM COM 83600C103 79 11,625 SH   SOLE   11,625 0 0
STERICYCLE INC COM COM 858912108 108,968 782,195 SH   SOLE   782,195 0 0
TANGOE INC COM COM 87582Y108 26,285 3,650,741 SH   SOLE   3,650,741 0 0
TELADOC INC COM 87918A105 651 29,205 SH   SOLE   29,205 0 0
TESLA MTRS INC COM COM 88160R101 247 993 SH   SOLE   993 0 0
TRANSDIGM GROUP INC COM COM 893641100 37,213 175,195 SH   SOLE   175,195 0 0
TRIMBLE NAVIGATION LTD COM COM 896239100 47,237 2,876,804 SH   SOLE   2,876,804 0 0
TYLER TECHNOLOGIES INC COM COM 902252105 43,479 291,197 SH   SOLE   291,197 0 0
ULTIMATE SOFTWARE GROUP INC CO COM 90385D107 336 1,878 SH   SOLE   1,878 0 0
UNDER ARMOUR INC CL A COM 904311107 726 7,500 SH   SOLE   7,500 0 0
UNION PAC CORP COM COM 907818108 217 2,450 SH   SOLE   2,450 0 0
UNITED PARCEL SERVICE INC CL B COM 911312106 231 2,342 SH   SOLE   2,342 0 0
UNITED TECHNOLOGIES CORP COM COM 913017109 400 4,492 SH   SOLE   4,492 0 0
US BANCORP DEL COM NEW COM 902973304 1,333 32,507 SH   SOLE   32,507 0 0
V F CORP COM COM 918204108 277 4,054 SH   SOLE   4,054 0 0
VENTAS INC COM COM 92276F100 2,082 37,142 SH   SOLE   37,142 0 0
VERISK ANALYTICS INC CL A COM 92345Y106 109,862 1,486,423 SH   SOLE   1,486,423 0 0
VERIZON COMMUNICATIONS INC COM COM 92343V104 310 7,118 SH   SOLE   7,118 0 0
VISA INC COM CL A COM 92826C839 116,588 1,673,671 SH   SOLE   1,673,671 0 0
W P CAREY INC COM COM 92936U109 326 5,635 SH   SOLE   5,635 0 0
WAGEWORKS INC COM COM 930427109 99,194 2,200,396 SH   SOLE   2,200,396 0 0
WASTE CONNECTIONS INC COM COM 941053100 83,851 1,726,047 SH   SOLE   1,726,047 0 0
WATSCO INC COM COM 942622200 782 6,600 SH   SOLE   6,600 0 0
WELLS FARGO & CO NEW COM COM 949746101 323 6,292 SH   SOLE   6,292 0 0
WELLTOWER INC COM 95040q104 316 4,672 SH   SOLE   4,672 0 0
WHOLE FOODS MKT INC COM COM 966837106 500 15,800 SH   SOLE   15,800 0 0
WSFS FINL CORP COM COM 929328102 726 25,194 SH   SOLE   25,194 0 0
ZOES KITCHEN INC COM COM 98979J109 401 10,144 SH   SOLE   10,144 0 0
BLACKROCK ENHANCED EQT DIV TR ETFS 09251A104 72 10,000 SH   SOLE   10,000 0 0
ISHARES S&P 500 GROWTH INDEX ETFS 464287309 322 2,988 SH   SOLE   2,988 0 0
VANGUARD FTSE ALL WORLD EX US ETFS 922042775 2,587 60,681 SH   SOLE   60,681 0 0
VANGUARD INDEX FDS REIT ETF ETFS 922908553 453 6,000 SH   SOLE   6,000 0 0
VANGUARD INTL EQUITY INDEX FD ETFS 922042858 428 12,925 SH   SOLE   12,925 0 0
VANGUARD SPECIALIZED PORTFOLIO ETFS 921908844 896 12,150 SH   SOLE   12,150 0 0
VANGUARD WHITEHALL FDS INC HIG ETFS 921946406 320 5,109 SH   SOLE   5,109 0 0