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 1,095 80,008 SH   SOLE   80,008 0 0
3M COMPANY COM 88579y101 707 4,039 SH   SOLE   4,039 0 0
A N S Y S INC COM COM 03662q105 160,265 1,766,005 SH   SOLE   1,766,005 0 0
AAC HOLDINGS INC SHS COM 000307108 24,159 1,058,698 SH   SOLE   1,058,698 0 0
ABBOTT LABORATORIES COM 002824100 457 11,622 SH   SOLE   11,622 0 0
ABBVIE INC COM COM 00287y109 505 8,155 SH   SOLE   8,155 0 0
AFFILIATED MANAGERS GROUP COM COM 008252108 1,018 7,233 SH   SOLE   7,233 0 0
ALIGN TECHNOLOGY INC COM COM 016255101 1,648 20,464 SH   SOLE   20,464 0 0
ALPHABET INC SHS CL C COM 02079k107 76,533 110,581 SH   SOLE   110,581 0 0
ALPHABET INC. CLASS A COM 02079k305 593 843 SH   SOLE   843 0 0
AMAZON COM INC COM COM 023135106 926 1,294 SH   SOLE   1,294 0 0
AMERICAN TOWER REIT INC (HLDG COM 03027x100 91,348 804,050 SH   SOLE   804,050 0 0
AMETEK INC NEW COM COM 031100100 844 18,254 SH   SOLE   18,254 0 0
AMGEN INC COM PV $0.0001 COM 031162100 231 1,515 SH   SOLE   1,515 0 0
AMPHENOL CORP NEW CL A COM 032095101 1,911 33,332 SH   SOLE   33,332 0 0
APPLE INC COM 037833100 613 6,417 SH   SOLE   6,417 0 0
APPLIED MINERALS INC COM 03823m100 14 80,000 SH   SOLE   80,000 0 0
ATMOS ENERGY CORP COM 049560105 244 3,000 SH   SOLE   3,000 0 0
ATRION CORP COM COM 049904105 4,398 10,278 SH   SOLE   10,278 0 0
AUTOMATIC DATA PROC COM 053015103 2,031 22,106 SH   SOLE   22,106 0 0
BARD C R INC COM COM 067383109 1,532 6,515 SH   SOLE   6,515 0 0
BECTON DICKINSON&CO COM 075887109 295 1,741 SH   SOLE   1,741 0 0
BERKSHIRE HATHAWAY INC DELAWA COM 084670108 1,519 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAYINC DEL CL COM 084670702 3,197 22,082 SH   SOLE   22,082 0 0
BIO TECHNE CORP COM STK COM 09073m104 23,990 212,735 SH   SOLE   212,735 0 0
BIOGEN INC COM 09062x103 21,276 87,982 SH   SOLE   87,982 0 0
BLACKBAUD INC COM 09227q100 70,477 1,037,947 SH   SOLE   1,037,947 0 0
CALAVO GROWERS INC COM COM 128246105 219 3,276 SH   SOLE   3,276 0 0
CAMPBELL SOUP CO COM COM 134429109 266 4,000 SH   SOLE   4,000 0 0
CANADIAN NATL RY CO COM COM 136375102 1,181 20,000 SH   SOLE   20,000 0 0
CAPITAL ONE FINL CORP COM COM 14040H105 1,629 25,643 SH   SOLE   25,643 0 0
CARMAX INC COM 143130102 109,305 2,229,354 SH   SOLE   2,229,354 0 0
CELGENE CORP COM COM 151020104 63,387 642,679 SH   SOLE   642,679 0 0
CERNER CORP COM COM 156782104 1,498 25,555 SH   SOLE   25,555 0 0
CHEVRON CORP COM 166764100 864 8,242 SH   SOLE   8,242 0 0
CHIPOTLE MEXICAN GRILL COM 169656105 20,521 50,951 SH   SOLE   50,951 0 0
CHURCH & DWIGHT INC COM COM 171340102 1,290 12,534 SH   SOLE   12,534 0 0
CISCO SYSTEMS INC COM COM 17275r102 2,007 69,971 SH   SOLE   69,971 0 0
COCA COLA COM COM 191216100 1,152 25,414 SH   SOLE   25,414 0 0
COGNIZANT TECHNOLOGY SOLUTIONS COM 192446102 1,400 24,452 SH   SOLE   24,452 0 0
COLGATE-PALMOLIVE CO COM 194162103 732 10,000 SH   SOLE   10,000 0 0
COMCAST CORP NEW CL A COM 20030n101 4,232 64,920 SH   SOLE   64,920 0 0
CORE LAB N.V. COM COM n22717107 2,352 18,985 SH   SOLE   18,985 0 0
COSTAR GROUP INC COM COM 22160n109 93,858 429,243 SH   SOLE   429,243 0 0
CROWN CASTLE REIT INC SHS COM 22822v101 6,974 68,753 SH   SOLE   68,753 0 0
DENTSPLY INTL INC COM 249030107 267 4,300 SH   SOLE   4,300 0 0
DISCOVER FINL SVCS COM 254709108 61,867 1,154,451 SH   SOLE   1,154,451 0 0
DISNEY (WALT) CO COM STK COM 254687106 856 8,747 SH   SOLE   8,747 0 0
DOUGLAS DYNAMICS INC COM COM 25960R105 1,303 50,647 SH   SOLE   50,647 0 0
DU PONT EI DE NEMOUR COM 263534109 312 4,815 SH   SOLE   4,815 0 0
DUKE REALTY CORP REIT COM 264411505 367 13,750 SH   SOLE   13,750 0 0
DULUTH HOLDINGS INC COM 26443v101 1,558 63,676 SH   SOLE   63,676 0 0
EAST WEST BANCORP INC COM 27579r104 1,604 46,928 SH   SOLE   46,928 0 0
ECOLAB INC COM 278865100 123,864 1,044,383 SH   SOLE   1,044,383 0 0
ELI LILLY & CO COM 532457108 573 7,278 SH   SOLE   7,278 0 0
ELLIE MAE INCCOM COM 28849p100 4,740 51,717 SH   SOLE   51,717 0 0
EMERSON ELECTRIC CO COM 291011104 544 10,420 SH   SOLE   10,420 0 0
ENTERPRISE PRDTS PRTN LPL P COM 293792107 564 19,275 SH   SOLE   19,275 0 0
ENVESTNET INC COM 29404k106 62,844 1,886,655 SH   SOLE   1,886,655 0 0
EQT CORP COM 26884l109 780 10,070 SH   SOLE   10,070 0 0
EQUITY RESIDENTIAL REIT COM 29476l107 415 6,026 SH   SOLE   6,026 0 0
EXAMWORKS GROUP INC COM 30066a105 7,180 206,040 SH   SOLE   206,040 0 0
EXPONENT INC COM 30214u102 33,907 580,502 SH   SOLE   580,502 0 0
EXPRESS SCRIPTS HLDG COM 30219g108 1,362 17,962 SH   SOLE   17,962 0 0
EXXON MOBIL CORP COM COM 30231g102 1,984 21,161 SH   SOLE   21,161 0 0
FASTENAL COMPANY COM 311900104 85,724 1,931,164 SH   SOLE   1,931,164 0 0
FINL ENGINES INC COM 317485100 16,778 648,539 SH   SOLE   648,539 0 0
FISERV INC WISC PV 1CT COM 337738108 10,163 93,467 SH   SOLE   93,467 0 0
FORTINET INC COM COM 34959E109 946 29,945 SH   SOLE   29,945 0 0
GENERAL ELECTRIC COM 369604103 3,862 122,694 SH   SOLE   122,694 0 0
GENUINE PARTS CO COM 372460105 500 4,934 SH   SOLE   4,934 0 0
GOOD TIMES RESTAURANTS INC COM COM 382140879 100 28,639 SH   SOLE   28,639 0 0
GRAMERCY PPTY TR COM COM 385002100 124 13,396 SH   SOLE   13,396 0 0
GUIDEWIRE SOFTWARE INC COM COM 40171V100 560 9,060 SH   SOLE   9,060 0 0
HARMONIC INC COM 413160102 30 10,625 SH   SOLE   10,625 0 0
HCP INC COM 40414l109 2,181 61,653 SH   SOLE   61,653 0 0
HEALTH CARE SVCS GROUP COM 421906108 82,640 1,997,094 SH   SOLE   1,997,094 0 0
HEICO CORP CL A COM 422806208 231 4,310 SH   SOLE   4,310 0 0
HOME DEPOT INC COM 437076102 414 3,242 SH   SOLE   3,242 0 0
IBM CORP COM 459200101 1,424 9,381 SH   SOLE   9,381 0 0
IDEXX LAB INC COM 45168d104 11,481 123,634 SH   SOLE   123,634 0 0
IHS INC CL A COM 451734107 1,239 10,719 SH   SOLE   10,719 0 0
ILLINOIS TOOL WORKS COM 452308109 228 2,190 SH   SOLE   2,190 0 0
ILLUMINA INC COM COM 452327109 55,150 392,859 SH   SOLE   392,859 0 0
IMAX CORP COM 45245e109 95,085 3,225,399 SH   SOLE   3,225,399 0 0
INTEL CORP COM 458140100 12,418 378,606 SH   SOLE   378,606 0 0
INTERCONTINENTAL EXCHANGE INC COM 45866F104 1,637 6,396 SH   SOLE   6,396 0 0
INTUIT COM COM 461202103 1,903 17,054 SH   SOLE   17,054 0 0
INTUITIVE SURGICAL INC COM 46120e602 101,905 154,073 SH   SOLE   154,073 0 0
INVENTURE FOODS INC COM COM 461212102 166 21,264 SH   SOLE   21,264 0 0
JOHNSON AND JOHNSON COM COM 478160104 11,589 95,540 SH   SOLE   95,540 0 0
JPMORGAN CHASE & CO COM 46625h100 321 5,162 SH   SOLE   5,162 0 0
KIMBERLY CLARK COM 494368103 325 2,363 SH   SOLE   2,363 0 0
LABORATORY CP AMER HLDGS COM 50540r409 2,373 18,213 SH   SOLE   18,213 0 0
LINCOLN NTL CORP IND NPV COM 534187109 208 5,354 SH   SOLE   5,354 0 0
LITHIA MOTORS INC COM 536797103 212 2,977 SH   SOLE   2,977 0 0
LKQ CORP COM 501889208 161,135 5,083,128 SH   SOLE   5,083,128 0 0
LYNAS CORP LTD AUD PA COM q5683j103 3 75,000 SH   SOLE   75,000 0 0
M & T BANK CORP COM 55261f104 499 4,224 SH   SOLE   4,224 0 0
MAGELLAN MIDSTREAM PRTNRS LP C COM 559080106 274 3,600 SH   SOLE   3,600 0 0
MARKEL CORP COM COM 570535104 97,116 101,929 SH   SOLE   101,929 0 0
MASTERCARD INC COM 57636q104 50,113 569,077 SH   SOLE   569,077 0 0
MCCORMICK & CO INC COM NON VTG COM 579780206 1,252 11,733 SH   SOLE   11,733 0 0
MERCK AND CO INC SHS COM 58933y105 1,372 23,814 SH   SOLE   23,814 0 0
MICROSOFT CORP COM 594918104 3,027 59,154 SH   SOLE   59,154 0 0
MIDDLEBY CORP COM COM 596278101 1,524 13,226 SH   SOLE   13,226 0 0
MONRO MUFFLER BRAKE INC COM COM 610236101 898 14,125 SH   SOLE   14,125 0 0
MOODY'S CORP COM 615369105 108,407 1,156,833 SH   SOLE   1,156,833 0 0
NASPERS LTD-N SHS SPON ADR COM 631512100 412 24,800 SH   SOLE   24,800 0 0
NATIONAL AMERICAN UNIVER COM 63245q105 31 15,000 SH   SOLE   15,000 0 0
NEOGEN CORP COM COM 640491106 551 9,800 SH   SOLE   9,800 0 0
O'REILLY AUTOMOTIVE INC COM 67103h107 18,702 68,986 SH   SOLE   68,986 0 0
ONEBEACON INSURANCE GRP COM g67742109 576 41,708 SH   SOLE   41,708 0 0
OXYSURE SYSTEMS INC COM COM 69208T101 0 10,000 SH   SOLE   10,000 0 0
PAYCHEX INC COM 704326107 3,562 59,860 SH   SOLE   59,860 0 0
PEPSICO INC COM 713448108 571 5,387 SH   SOLE   5,387 0 0
PFIZER INC COM 717081103 1,153 32,752 SH   SOLE   32,752 0 0
PHILIP MORRIS INTL COM 718172109 346 3,403 SH   SOLE   3,403 0 0
PINNACLE WEST CAP CORP COM 723484101 324 4,000 SH   SOLE   4,000 0 0
PNC FINCL SERVICES GROUP COM 693475105 2,110 25,924 SH   SOLE   25,924 0 0
POOL CORPORATION COM 73278l105 300 3,188 SH   SOLE   3,188 0 0
POTASH CORP SASKATCHEWAN COM 73755l107 5,584 343,871 SH   SOLE   343,871 0 0
PRA GROUP INC COM 69354n106 35,983 1,490,576 SH   SOLE   1,490,576 0 0
PRICE T ROWE GROUP INC COM 74144t108 11,742 160,914 SH   SOLE   160,914 0 0
PROCTER & GAMBLE CO COM 742718109 18,588 219,533 SH   SOLE   219,533 0 0
PROS HOLDINGS INC COM 74346y103 14,603 837,786 SH   SOLE   837,786 0 0
QUALCOMM INC COM 747525103 37,505 700,104 SH   SOLE   700,104 0 0
RED HAT INC COM 756577102 139,822 1,925,925 SH   SOLE   1,925,925 0 0
ROPER TECHNOLOGIES INC COM 776696106 121,743 713,781 SH   SOLE   713,781 0 0
RPM INTERNATIONAL INC COM 749685103 205 4,100 SH   SOLE   4,100 0 0
RUSH ENTERPRISES INC CL A COM 781846209 364 16,905 SH   SOLE   16,905 0 0
S&P GLOBAL COM 78409v104 73,646 686,609 SH   SOLE   686,609 0 0
SBA COMMUNICATIONS CRP A COM 78388j106 14,630 135,536 SH   SOLE   135,536 0 0
SCHLUMBERGER LTD COM 806857108 13,347 168,779 SH   SOLE   168,779 0 0
SEI INVESTMENTS CO COM 784117103 125,811 2,615,074 SH   SOLE   2,615,074 0 0
SIGNATURE BK NEW YORK N Y COM COM 82669G104 1,392 11,140 SH   SOLE   11,140 0 0
SIGNET JEWELERS LTD SHS COM g81276100 71,690 869,923 SH   SOLE   869,923 0 0
SILVER WHEATON CORP COM 828336107 353 15,000 SH   SOLE   15,000 0 0
SMITH & NEPHEW P L C ADS COM 83175M205 378 11,000 SH   SOLE   11,000 0 0
SOTHERLY HOTELS INC COM COM 83600C103 66 11,625 SH   SOLE   11,625 0 0
STERICYCLE INC COM COM 858912108 93,153 894,674 SH   SOLE   894,674 0 0
TELADOC INC COM 87918a105 1,402 87,502 SH   SOLE   87,502 0 0
TESLA MTRS INC COM COM 88160R101 211 993 SH   SOLE   993 0 0
TRACTOR SUPPLY COMP COM 892356106 1,721 18,877 SH   SOLE   18,877 0 0
TRANSDIGM GROUP INC COM 893641100 75,732 287,202 SH   SOLE   287,202 0 0
TRIMBLE NAV LTD COM 896239100 71,146 2,920,599 SH   SOLE   2,920,599 0 0
TYLER TECHS INC DEL COM COM 902252105 97,904 587,270 SH   SOLE   587,270 0 0
U S BANCORP COM 902973304 1,278 31,686 SH   SOLE   31,686 0 0
ULTIMATE SOFTWARE GP COM 90385d107 369 1,753 SH   SOLE   1,753 0 0
UNDER ARMOUR INC COM 904311107 1,067 26,580 SH   SOLE   26,580 0 0
UNDER ARMOUR INC, CLASS C COM 904311206 1,011 27,768 SH   SOLE   27,768 0 0
UNITED PARCEL SERVICE INC CL B COM 911312106 291 2,702 SH   SOLE   2,702 0 0
UNITED TECHS CORP COM COM 913017109 432 4,210 SH   SOLE   4,210 0 0
VENTAS INC REIT COM 92276f100 2,252 30,932 SH   SOLE   30,932 0 0
VERISK ANALYTICS INC CLASS COM 92345y106 106,350 1,311,669 SH   SOLE   1,311,669 0 0
VERIZON COMMUNICATNS COM COM 92343v104 395 7,076 SH   SOLE   7,076 0 0
VISA INC CL A SHRS COM 92826c839 115,597 1,558,541 SH   SOLE   1,558,541 0 0
W R BERKLEY CORP COM 084423102 2,856 47,658 SH   SOLE   47,658 0 0
W.P. CAREY INC. REIT COM 92936u109 395 5,696 SH   SOLE   5,696 0 0
WABTEC CORP COM COM 929740108 30,560 435,135 SH   SOLE   435,135 0 0
WAGEWORKS INC COM 930427109 123,741 2,068,905 SH   SOLE   2,068,905 0 0
WASTE CONNECTIONS INC NPV COM 94106b101 69,118 959,310 SH   SOLE   959,310 0 0
WATSCO INC COM COM 942622200 802 5,700 SH   SOLE   5,700 0 0
WELLS FARGO & CO COM 949746101 306 6,474 SH   SOLE   6,474 0 0
WELLTOWER INC COM 95040q104 383 5,026 SH   SOLE   5,026 0 0
WHOLE FOODS MKT INC COM COM 966837106 506 15,800 SH   SOLE   15,800 0 0
WSFS FINL CORP COM COM 929328102 872 27,092 SH   SOLE   27,092 0 0
ZOES KITCHEN INC COM COM 98979J109 346 9,529 SH   SOLE   9,529 0 0
BLACKROCK ENHANCED EQT DIV TR ETFS 09251A104 79 10,000 SH   SOLE   10,000 0 0
ISHARES MSCI EAFE ETF ETFS 464287465 209 3,749 SH   SOLE   3,749 0 0
SPDR GOLD TRUST ETFS 78463v107 202 1,600 SH   SOLE   1,600 0 0
VANGUARD DIVIDEND APPREC ETFS 921908844 1,046 12,565 SH   SOLE   12,565 0 0
VANGUARD FTSE ALL WORLD EX US ETFS 922042775 2,586 60,347 SH   SOLE   60,347 0 0
VANGUARD FTSE EMERGING MARK ET ETFS 922042858 455 12,925 SH   SOLE   12,925 0 0
VANGUARD HIGH DVD YIELD ETF ETFS 921946406 441 6,175 SH   SOLE   6,175 0 0
VANGUARD INDEX FDS TOTAL STK M ETFS 922908769 280 2,615 SH   SOLE   2,615 0 0
VANGUARD REIT ETF ETFS 922908553 799 9,015 SH   SOLE   9,015 0 0
VANGUARD SHORT-TERM GOV BD ETFS 92206c102 444 7,225 SH   SOLE   7,225 0 0