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 7,309 472,488 SH   SOLE   472,488 0 0
3M COMPANY COM 88579y101 673 4,039 SH   SOLE   4,039 0 0
A N S Y S INC COM COM 03662q105 157,696 1,762,751 SH   SOLE   1,762,751 0 0
AAC HOLDINGS INC SHS COM 000307108 16,969 857,435 SH   SOLE   857,435 0 0
ABBOTT LABORATORIES COM 002824100 486 11,622 SH   SOLE   11,622 0 0
ABBVIE INC COM COM 00287Y109 466 8,155 SH   SOLE   8,155 0 0
ALPHABET INC SHS CL C COM 02079k107 75,774 101,717 SH   SOLE   101,717 0 0
ALPHABET INC. CLASS A COM 02079k305 238 312 SH   SOLE   312 0 0
AMAZON COM INC COM COM 023135106 406 684 SH   SOLE   684 0 0
AMERICAN TOWER REIT INC (HLDG COM 03027x100 83,088 811,644 SH   SOLE   811,644 0 0
AMGEN INC COM PV $0.0001 COM 031162100 227 1,515 SH   SOLE   1,515 0 0
APPLE INC COM 037833100 656 6,017 SH   SOLE   6,017 0 0
APPLIED MINERALS INC COM 03823m100 14 80,000 SH   SOLE   80,000 0 0
ATMOS ENERGY CORP COM 049560105 223 3,000 SH   SOLE   3,000 0 0
ATRION CORP COM COM 049904105 4,208 10,644 SH   SOLE   10,644 0 0
AUTOMATIC DATA PROC COM 053015103 1,983 22,106 SH   SOLE   22,106 0 0
BECTON DICKINSON&CO COM 075887109 264 1,741 SH   SOLE   1,741 0 0
BERKSHIRE HATHAWAY INC DELAWA COM 084670108 1,494 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAYINC DEL CL COM 084670702 3,133 22,082 SH   SOLE   22,082 0 0
BIO TECHNE CORP COM STK COM 09073m104 19,002 201,040 SH   SOLE   201,040 0 0
BIOGEN INC COM 09062x103 29,524 113,413 SH   SOLE   113,413 0 0
BLACKBAUD INC COM 09227q100 63,063 1,002,748 SH   SOLE   1,002,748 0 0
CAMPBELL SOUP CO COM COM 134429109 255 4,000 SH   SOLE   4,000 0 0
CANADIAN NATL RY CO COM COM 136375102 1,249 20,000 SH   SOLE   20,000 0 0
CAPITAL ONE FINL CORP COM COM 14040H105 1,777 25,643 SH   SOLE   25,643 0 0
CARE CAPITAL PROPERTIES INC SH COM 141624106 206 7,681 SH   SOLE   7,681 0 0
CARMAX INC COM 143130102 91,629 1,793,124 SH   SOLE   1,793,124 0 0
CELGENE CORP COM COM 151020104 63,008 629,516 SH   SOLE   629,516 0 0
CHEVRON CORP COM 166764100 783 8,212 SH   SOLE   8,212 0 0
CHIPOTLE MEXICAN GRILL COM 169656105 27,475 58,336 SH   SOLE   58,336 0 0
CISCO SYSTEMS INC COM COM 17275r102 2,011 70,646 SH   SOLE   70,646 0 0
COCA COLA COM COM 191216100 1,309 28,214 SH   SOLE   28,214 0 0
COGNIZANT TECHNOLOGY SOLUTIONS COM 192446102 251 4,000 SH   SOLE   4,000 0 0
COLGATE-PALMOLIVE CO COM 194162103 706 10,000 SH   SOLE   10,000 0 0
COMCAST CORP NEW CL A COM 20030n101 3,996 65,420 SH   SOLE   65,420 0 0
CORE LAB N.V. COM COM n22717107 2,134 18,985 SH   SOLE   18,985 0 0
COSTAR GROUP INC COM COM 22160n109 79,737 423,749 SH   SOLE   423,749 0 0
CROWN CASTLE REIT INC SHS COM 22822v101 6,086 70,363 SH   SOLE   70,363 0 0
DENTSPLY INTL INC COM 249030107 290 4,700 SH   SOLE   4,700 0 0
DISCOVER FINL SVCS COM 254709108 71,437 1,402,924 SH   SOLE   1,402,924 0 0
DISNEY (WALT) CO COM STK COM 254687106 870 8,762 SH   SOLE   8,762 0 0
DONALDSON INC COM COM 257651109 228 7,150 SH   SOLE   7,150 0 0
DOUGLAS DYNAMICS INC COM COM 25960R105 1,088 47,498 SH   SOLE   47,498 0 0
DU PONT EI DE NEMOUR COM 263534109 305 4,815 SH   SOLE   4,815 0 0
DUKE REALTY CORP REIT COM 264411505 332 14,750 SH   SOLE   14,750 0 0
DULUTH HOLDINGS INC COM 26443v101 1,100 56,455 SH   SOLE   56,455 0 0
EAST WEST BANCORP INC COM 27579r104 276 8,500 SH   SOLE   8,500 0 0
ECOLAB INC COM 278865100 115,833 1,038,671 SH   SOLE   1,038,671 0 0
ELI LILLY & CO COM 532457108 538 7,478 SH   SOLE   7,478 0 0
ELLIE MAE INCCOM COM 28849p100 4,599 50,734 SH   SOLE   50,734 0 0
EMERSON ELECTRIC CO COM 291011104 540 9,939 SH   SOLE   9,939 0 0
ENTERPRISE PRDTS PRTN LPL P COM 293792107 475 19,275 SH   SOLE   19,275 0 0
ENVESTNET INC COM 29404k106 51,717 1,901,348 SH   SOLE   1,901,348 0 0
EQT CORP COM 26884l109 778 11,570 SH   SOLE   11,570 0 0
EQUITY RESIDENTIAL REIT COM 29476l107 452 6,026 SH   SOLE   6,026 0 0
EXAMWORKS GROUP INC COM 30066a105 64,082 2,167,863 SH   SOLE   2,167,863 0 0
EXPONENT INC COM 30214u102 26,187 513,363 SH   SOLE   513,363 0 0
EXPRESS SCRIPTS HLDG COM 30219g108 1,234 17,962 SH   SOLE   17,962 0 0
EXXON MOBIL CORP COM COM 30231g102 1,811 21,661 SH   SOLE   21,661 0 0
FASTENAL COMPANY COM 311900104 102,852 2,099,011 SH   SOLE   2,099,011 0 0
FINL ENGINES INC COM 317485100 23,978 762,887 SH   SOLE   762,887 0 0
FISERV INC WISC PV 1CT COM 337738108 6,965 67,903 SH   SOLE   67,903 0 0
FORTINET INC COM COM 34959E109 892 29,130 SH   SOLE   29,130 0 0
GENERAL ELECTRIC COM 369604103 3,904 122,794 SH   SOLE   122,794 0 0
GENUINE PARTS CO COM 372460105 490 4,934 SH   SOLE   4,934 0 0
GOOD TIMES RESTAURANTS INC COM COM 382140879 113 28,326 SH   SOLE   28,326 0 0
GUIDEWIRE SOFTWARE INC COM COM 40171V100 491 9,019 SH   SOLE   9,019 0 0
HCP INC COM 40414l109 2,992 91,842 SH   SOLE   91,842 0 0
HEALTH CARE SVCS GROUP COM 421906108 72,441 1,967,957 SH   SOLE   1,967,957 0 0
HEICO CORP CL A COM 422806208 203 4,264 SH   SOLE   4,264 0 0
HOME DEPOT INC COM 437076102 433 3,242 SH   SOLE   3,242 0 0
IBM CORP COM 459200101 1,500 9,906 SH   SOLE   9,906 0 0
IDEXX LAB INC COM 45168d104 9,559 122,053 SH   SOLE   122,053 0 0
ILLINOIS TOOL WORKS COM 452308109 229 2,240 SH   SOLE   2,240 0 0
ILLUMINA INC COM COM 452327109 36,555 225,492 SH   SOLE   225,492 0 0
IMAX CORP COM 45245e109 98,508 3,168,491 SH   SOLE   3,168,491 0 0
INTEL CORP COM 458140100 12,320 380,840 SH   SOLE   380,840 0 0
INTUITIVE SURGICAL INC COM 46120e602 107,558 178,950 SH   SOLE   178,950 0 0
INVENTURE FOODS INC COM COM 461212102 119 21,034 SH   SOLE   21,034 0 0
JOHNSON AND JOHNSON COM COM 478160104 10,475 96,814 SH   SOLE   96,814 0 0
JPMORGAN CHASE & CO COM 46625h100 316 5,334 SH   SOLE   5,334 0 0
KIMBERLY CLARK COM 494368103 318 2,363 SH   SOLE   2,363 0 0
LABORATORY CP AMER HLDGS COM 50540r409 2,138 18,253 SH   SOLE   18,253 0 0
LINCOLN NTL CORP IND NPV COM 534187109 210 5,354 SH   SOLE   5,354 0 0
LITHIA MOTORS INC COM 536797103 201 2,300 SH   SOLE   2,300 0 0
LKQ CORP COM 501889208 157,677 4,938,208 SH   SOLE   4,938,208 0 0
LYNAS CORP LTD AUD PA COM q5683j103 5 75,000 SH   SOLE   75,000 0 0
M & T BANK CORP COM 55261f104 469 4,224 SH   SOLE   4,224 0 0
MAGELLAN MIDSTREAM PRTNRS LP C COM 559080106 248 3,600 SH   SOLE   3,600 0 0
MARKEL CORP COM COM 570535104 90,977 102,041 SH   SOLE   102,041 0 0
MASTERCARD INC COM 57636q104 53,591 567,102 SH   SOLE   567,102 0 0
MCCORMICK & CO INC COM NON VTG COM 579780206 1,167 11,733 SH   SOLE   11,733 0 0
MCGRAW HILL FINANCIAL INC SH COM 580645109 65,987 666,670 SH   SOLE   666,670 0 0
MERCK AND CO INC SHS COM 58933y105 1,260 23,814 SH   SOLE   23,814 0 0
MICROSOFT CORP COM 594918104 3,267 59,154 SH   SOLE   59,154 0 0
MIDDLEBY CORP COM COM 596278101 1,310 12,272 SH   SOLE   12,272 0 0
MONRO MUFFLER BRAKE INC COM COM 610236101 876 12,251 SH   SOLE   12,251 0 0
MOODY'S CORP COM 615369105 117,953 1,221,554 SH   SOLE   1,221,554 0 0
NASPERS LTD-N SHS SPON ADR COM 631512100 348 24,800 SH   SOLE   24,800 0 0
NATIONAL AMERICAN UNIVER COM 63245q105 21 15,000 SH   SOLE   15,000 0 0
NEOGEN CORP COM COM 640491106 493 9,800 SH   SOLE   9,800 0 0
O'REILLY AUTOMOTIVE INC COM 67103h107 16,378 59,849 SH   SOLE   59,849 0 0
ONEBEACON INSURANCE GRP COM g67742109 530 41,644 SH   SOLE   41,644 0 0
OXYSURE SYSTEMS INC COM COM 69208T101 0 10,000 SH   SOLE   10,000 0 0
PAYCHEX INC COM 704326107 3,287 60,860 SH   SOLE   60,860 0 0
PEPSICO INC COM 713448108 616 6,007 SH   SOLE   6,007 0 0
PERFORMANCE SPORTS GROUP LTD C COM 71377G100 114 35,946 SH   SOLE   35,946 0 0
PFIZER INC COM 717081103 977 32,949 SH   SOLE   32,949 0 0
PHILIP MORRIS INTL COM 718172109 344 3,503 SH   SOLE   3,503 0 0
PINNACLE WEST CAP CORP COM 723484101 330 4,400 SH   SOLE   4,400 0 0
PNC FINCL SERVICES GROUP COM 693475105 2,192 25,924 SH   SOLE   25,924 0 0
POOL CORPORATION COM 73278l105 280 3,188 SH   SOLE   3,188 0 0
POTASH CORP SASKATCHEWAN COM 73755l107 6,113 359,153 SH   SOLE   359,153 0 0
PRA GROUP INC COM 69354n106 53,420 1,817,626 SH   SOLE   1,817,626 0 0
PRICE T ROWE GROUP INC COM 74144t108 11,896 161,939 SH   SOLE   161,939 0 0
PROCTER & GAMBLE CO COM 742718109 18,683 226,983 SH   SOLE   226,983 0 0
QUALCOMM INC COM 747525103 36,430 712,349 SH   SOLE   712,349 0 0
RANGE RESOURCES CORP DEL COM 75281a109 301 9,288 SH   SOLE   9,288 0 0
RED HAT INC COM 756577102 143,302 1,923,256 SH   SOLE   1,923,256 0 0
ROPER TECHNOLOGIES INC COM 776696106 108,861 595,619 SH   SOLE   595,619 0 0
RUSH ENTERPRISES INC CL A COM 781846209 345 18,917 SH   SOLE   18,917 0 0
SBA COMMUNICATIONS CRP A COM 78388j106 8,773 87,583 SH   SOLE   87,583 0 0
SCHLUMBERGER LTD COM 806857108 13,787 186,948 SH   SOLE   186,948 0 0
SEI INVESTMENTS CO COM 784117103 111,199 2,583,022 SH   SOLE   2,583,022 0 0
SIGNET JEWELERS LTD SHS COM g81276100 87,062 701,943 SH   SOLE   701,943 0 0
SILVER WHEATON CORP COM 828336107 249 15,000 SH   SOLE   15,000 0 0
SMITH & NEPHEW P L C ADS COM 83175M205 367 11,000 SH   SOLE   11,000 0 0
SOTHERLY HOTELS INC COM COM 83600C103 60 11,625 SH   SOLE   11,625 0 0
STERICYCLE INC COM COM 858912108 106,686 845,441 SH   SOLE   845,441 0 0
TELADOC INC COM 87918a105 376 39,192 SH   SOLE   39,192 0 0
TESLA MTRS INC COM COM 88160R101 228 993 SH   SOLE   993 0 0
TRANSDIGM GROUP INC COM 893641100 59,930 271,989 SH   SOLE   271,989 0 0
TRIMBLE NAV LTD COM 896239100 73,591 2,967,371 SH   SOLE   2,967,371 0 0
TYLER TECHS INC DEL COM COM 902252105 62,896 489,047 SH   SOLE   489,047 0 0
U S BANCORP COM 902973304 1,286 31,686 SH   SOLE   31,686 0 0
ULTIMATE SOFTWARE GP COM 90385d107 338 1,748 SH   SOLE   1,748 0 0
UNDER ARMOUR INC COM 904311107 594 7,000 SH   SOLE   7,000 0 0
UNITED PARCEL SERVICE INC CL B COM 911312106 247 2,342 SH   SOLE   2,342 0 0
UNITED TECHS CORP COM COM 913017109 461 4,610 SH   SOLE   4,610 0 0
VENTAS INC REIT COM 92276f100 2,274 36,113 SH   SOLE   36,113 0 0
VERISK ANALYTICS INC CLASS COM 92345y106 100,482 1,257,277 SH   SOLE   1,257,277 0 0
VERIZON COMMUNICATNS COM COM 92343v104 391 7,226 SH   SOLE   7,226 0 0
VISA INC CL A SHRS COM 92826c839 121,116 1,583,630 SH   SOLE   1,583,630 0 0
W R BERKLEY CORP COM 084423102 2,975 52,928 SH   SOLE   52,928 0 0
W.P. CAREY INC. REIT COM 92936u109 353 5,676 SH   SOLE   5,676 0 0
WAGEWORKS INC COM 930427109 104,279 2,060,434 SH   SOLE   2,060,434 0 0
WASTE CONNECTIONS INC COM 941053100 76,735 1,188,025 SH   SOLE   1,188,025 0 0
WATSCO INC COM COM 942622200 903 6,700 SH   SOLE   6,700 0 0
WELLS FARGO & CO COM 949746101 316 6,539 SH   SOLE   6,539 0 0
WELLTOWER INC COM 95040q104 349 5,026 SH   SOLE   5,026 0 0
WHOLE FOODS MKT INC COM COM 966837106 492 15,800 SH   SOLE   15,800 0 0
WSFS FINL CORP COM COM 929328102 879 27,028 SH   SOLE   27,028 0 0
ZOES KITCHEN INC COM COM 98979J109 370 9,497 SH   SOLE   9,497 0 0
BLACKROCK ENHANCED EQT DIV TR ETFS 09251A104 75 10,000 SH   SOLE   10,000 0 0
ISHARES MSCI EAFE ETF ETFS 464287465 214 3,749 SH   SOLE   3,749 0 0
VANGUARD DIVIDEND APPREC ETFS 921908844 1,021 12,565 SH   SOLE   12,565 0 0
VANGUARD FTSE ALL WORLD EX US ETFS 922042775 2,604 60,347 SH   SOLE   60,347 0 0
VANGUARD FTSE EMERGING MARK ET ETFS 922042858 447 12,925 SH   SOLE   12,925 0 0
VANGUARD HIGH DVD YIELD ETF ETFS 921946406 411 5,950 SH   SOLE   5,950 0 0
VANGUARD INDEX FDS TOTAL STK M ETFS 922908769 274 2,615 SH   SOLE   2,615 0 0
VANGUARD REIT ETF ETFS 922908553 739 8,815 SH   SOLE   8,815 0 0
VANGUARD SHORT-TERM GOV BD ETFS 92206c102 442 7,225 SH   SOLE   7,225 0 0