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
3D SYSTEMS CORP COM 88554D205 115,689 2,142,794 SH   SOLE   2,142,794 0 0
3M CO COM 88579Y101 545 4,565 SH   SOLE   4,565 0 0
ABBOTT LABORATORIES COM 002824100 672 20,247 SH   SOLE   20,247 0 0
ABBVIE INC COM 00287Y109 892 19,947 SH   SOLE   19,947 0 0
ACTUANT CORP A COM 00508X203 2,606 67,092 SH   SOLE   67,092 0 0
ALTERA CORP COM 021441100 424 11,408 SH   SOLE   11,408 0 0
AMERICAN PUBLIC EDUCATION INC COM 02913V103 22,795 603,037 SH   SOLE   603,037 0 0
AMERICAN TOWER CORP COM 03027X100 54,348 733,150 SH   SOLE   733,150 0 0
ANADARKO PETROLEUM CORP COM 032511107 679 7,300 SH   SOLE   7,300 0 0
ANSYS INC COM 03662Q105 201,480 2,328,713 SH   SOLE   2,328,713 0 0
APACHE CORP COM 037411105 216 2,541 SH   SOLE   2,541 0 0
APPLE COMPUTER INC COM 037833100 841 1,765 SH   SOLE   1,765 0 0
APPLIED MINERALS COM 03823m100 226 207,600 SH   SOLE   207,600 0 0
ATRION CORP COM 049904105 1,319 5,097 SH   SOLE   5,097 0 0
AUTOMATIC DATA PROCESSING COM 053015103 2,332 32,225 SH   SOLE   32,225 0 0
BECTON DICKINSON & CO COM 075887109 225 2,248 SH   SOLE   2,248 0 0
BERKSHIRE HATHAWAY INC COM 084670108 1,193 7 SH   SOLE   7 0 0
BERKSHIRE HATHAWAY INC. DEL CL COM 084670702 2,754 24,260 SH   SOLE   24,260 0 0
CANADIAN NATIONAL RAILROAD CO COM 136375102 1,014 10,000 SH   SOLE   10,000 0 0
CAPITAL ONE FINANCIAL COM 14040H105 1,925 28,009 SH   SOLE   28,009 0 0
CARMAX INC COM 143130102 6,259 129,135 SH   SOLE   129,135 0 0
CARTERS, INC. COM 146229109 25,473 335,651 SH   SOLE   335,651 0 0
CELGENE CORP COM 151020104 97,527 632,728 SH   SOLE   632,728 0 0
CHEVRON CORP COM 166764100 1,569 12,910 SH   SOLE   12,910 0 0
CISCO SYSTEMS INC COM 17275R102 2,537 108,263 SH   SOLE   108,263 0 0
CLEAN HARBORS INC COM 184496107 71,432 1,217,731 SH   SOLE   1,217,731 0 0
COCA COLA CO COM 191216100 1,029 27,162 SH   SOLE   27,162 0 0
COLGATE-PALMOLIVE COM 194162103 593 10,000 SH   SOLE   10,000 0 0
COMCAST CORP - A COM 20030N101 592 13,125 SH   SOLE   13,125 0 0
COMCAST CORP - A - SPL COM 20030N200 3,672 84,713 SH   SOLE   84,713 0 0
CONCHO RESOURCES INC COM 20605P101 102,604 942,969 SH   SOLE   942,969 0 0
CONCUR TECHNOLOGIES, INC. COM 206708109 110,645 1,001,309 SH   SOLE   1,001,309 0 0
CORE LABORATORIES NV COM N22717107 58,474 345,569 SH   SOLE   345,569 0 0
COSTAR GROUP INC. COM 22160n109 88,416 526,563 SH   SOLE   526,563 0 0
CROWN CASTLE INTL CORP COM 228227104 4,871 66,699 SH   SOLE   66,699 0 0
DEALERTRACK TECHNOLOGIES INC COM 242309102 67,997 1,587,231 SH   SOLE   1,587,231 0 0
DENTSPLY INTL COM 249030107 809 18,640 SH   SOLE   18,640 0 0
DONALDSON INC COM 257651109 5,033 132,007 SH   SOLE   132,007 0 0
DUKE REALTY CORP COM 264411505 240 15,550 SH   SOLE   15,550 0 0
EAST WEST BANCORP INC COM 27579R104 489 15,300 SH   SOLE   15,300 0 0
ECOLAB INC COM 278865100 107,508 1,088,575 SH   SOLE   1,088,575 0 0
ELI LILLY & CO COM 532457108 523 10,399 SH   SOLE   10,399 0 0
EMERSON COM 291011104 427 6,600 SH   SOLE   6,600 0 0
ENTERPRISE PRODUCTS PARTNERS L COM 293792107 534 8,750 SH   SOLE   8,750 0 0
ENVESTNET INC COM 29404K106 243 7,850 SH   SOLE   7,850 0 0
EQT CORPORATION COM 26884L109 5,034 56,741 SH   SOLE   56,741 0 0
EQUITY RESIDENTIAL PROPERTYS I COM 29476l107 335 6,248 SH   SOLE   6,248 0 0
EUROSEAS LTD COM Y23592200 17 11,400 SH   SOLE   11,400 0 0
EXAMWORKS GROUP INC. COM 30066a105 27,743 1,067,454 SH   SOLE   1,067,454 0 0
EXONE COM 302104104 202 4,750 SH   SOLE   4,750 0 0
EXPEDITORS INTERNATIONAL COM 302130109 129,110 2,930,314 SH   SOLE   2,930,314 0 0
EXPONENT INC. COM 30214U102 38,304 533,185 SH   SOLE   533,185 0 0
EXPRESS SCRIPTS INC COM 30219G108 1,115 18,036 SH   SOLE   18,036 0 0
EXXON MOBIL CORP COM 30231G102 1,791 20,817 SH   SOLE   20,817 0 0
FASTENAL CO COM 311900104 265,135 5,274,213 SH   SOLE   5,274,213 0 0
FINANCIAL ENGINES INC COM 317485100 62,357 1,049,169 SH   SOLE   1,049,169 0 0
FISERV INC COM 337738108 3,538 35,016 SH   SOLE   35,016 0 0
FORTINET INC COM 34959e109 1,341 66,202 SH   SOLE   66,202 0 0
FREEPORT MCMORAN COPPER & GOLD COM 35671D857 507 15,314 SH   SOLE   15,314 0 0
GENERAL ELECTRIC COM 369604103 3,027 126,711 SH   SOLE   126,711 0 0
GENUINE PARTS COMPANY COM 372460105 283 3,499 SH   SOLE   3,499 0 0
GILEAD SCIENCES INC. COM 375558103 390 6,200 SH   SOLE   6,200 0 0
GOOGLE INC CL A COM 38259P508 394 450 SH   SOLE   450 0 0
HCP INC COM 40414L109 5,070 123,812 SH   SOLE   123,812 0 0
HEALTHCARE SERVICES GROUP INC COM 421906108 57,668 2,238,648 SH   SOLE   2,238,648 0 0
HESS CORPORATION COM 42809h107 464 6,002 SH   SOLE   6,002 0 0
HIBBETT SPORTS INC COM 428567101 690 12,294 SH   SOLE   12,294 0 0
HOME DEPOT COM 437076102 227 2,999 SH   SOLE   2,999 0 0
HOVNANIAN ENTERPRISES INC COM 442487203 235 45,000 SH   SOLE   45,000 0 0
IDEXX LABORATORIES, INC. COM 45168D104 207 2,078 SH   SOLE   2,078 0 0
ILLUMINA INC COM 452327109 26,180 323,893 SH   SOLE   323,893 0 0
INNERWORKINGS INC COM 45773Y105 20,654 2,103,306 SH   SOLE   2,103,306 0 0
INTEL CORP COM 458140100 14,218 620,317 SH   SOLE   620,317 0 0
INTERMAP TECHNOLOGIES CORP COM 458977204 28 85,000 SH   SOLE   85,000 0 0
INTL BUSINESS MACH CORP COM 459200101 2,770 14,959 SH   SOLE   14,959 0 0
INTUITIVE SURGICAL INC COM 46120e602 394 1,046 SH   SOLE   1,046 0 0
INVENTURE FOODS INC COM 461212102 170 16,180 SH   SOLE   16,180 0 0
J P MORGAN CHASE & CO COM 46625H100 606 11,730 SH   SOLE   11,730 0 0
JACOBS ENGINEERING CP INC COM 469814107 88,183 1,515,688 SH   SOLE   1,515,688 0 0
JAMBA, INC. COM 47023A101 201 15,000 SH   SOLE   15,000 0 0
JOHNSON & JOHNSON COM 478160104 8,905 102,718 SH   SOLE   102,718 0 0
JOHNSON CONTROLS INC COM 478366107 208 5,016 SH   SOLE   5,016 0 0
KINDER MORGAN MGT LLC COM 49455U100 720 9,606 SH   SOLE   9,606 0 0
LABORATORY CORP OF AMERICA HOL COM 50540R409 6,463 65,186 SH   SOLE   65,186 0 0
LAKE SHORE GOLD CORP COM 510728108 10 25,000 SH   SOLE   25,000 0 0
LANDAUER, INC. COM 51476k103 318 6,212 SH   SOLE   6,212 0 0
LINCOLN NATL CORP COM 534187109 283 6,736 SH   SOLE   6,736 0 0
LKQ CORP COM 501889208 153,831 4,826,830 SH   SOLE   4,826,830 0 0
LYNAS CORP LTD COM Q5683J103 49 135,000 SH   SOLE   135,000 0 0
M&T BANK CORP COM 55261F104 351 3,138 SH   SOLE   3,138 0 0
MACY'S, INC. COM 55616P104 254 5,863 SH   SOLE   5,863 0 0
MAG SILVER CORP COM 55903Q104 529 90,000 SH   SOLE   90,000 0 0
MAGELLAN MIDSTREAM PARTNERS LP COM 559080106 226 4,000 SH   SOLE   4,000 0 0
MARKEL CORP COM 570535104 119,260 230,334 SH   SOLE   230,334 0 0
MASTERCARD INC CL A COM 57636Q104 1,692 2,515 SH   SOLE   2,515 0 0
McCORMICK & CO COM 579780206 951 14,695 SH   SOLE   14,695 0 0
MCEWEN MINING INC COM 58039P107 202 84,000 SH   SOLE   84,000 0 0
MERCK & CO COM 58933Y105 1,171 24,587 SH   SOLE   24,587 0 0
MERIDIAN BIOSCIENCE INC. COM 589584101 326 13,800 SH   SOLE   13,800 0 0
MICROSOFT CORP COM 594918104 1,993 59,874 SH   SOLE   59,874 0 0
MIDDLEBY CORP COM 596278101 2,020 9,669 SH   SOLE   9,669 0 0
MONRO MUFFLER BRAKE COM 610236101 576 12,401 SH   SOLE   12,401 0 0
MONSANTO CO COM 61166W101 14,054 134,657 SH   SOLE   134,657 0 0
MOODYS CORP COM 615369105 14,287 203,145 SH   SOLE   203,145 0 0
MOSIAC COMPANY COM 61945C103 7,419 172,449 SH   SOLE   172,449 0 0
NANOSPHERE INC COM 63009f105 90 45,000 SH   SOLE   45,000 0 0
NATIONAL AMERICAN UNIV HOLDING COM 63245Q105 5,432 1,583,533 SH   SOLE   1,583,533 0 0
NATIONAL INFORMATION CONSORTIU COM 62914b100 22,590 977,500 SH   SOLE   977,500 0 0
NEOGEN CORP COM 640491106 437 7,200 SH   SOLE   7,200 0 0
NESTLE S.A. COM 641069406 316 4,524 SH   SOLE   4,524 0 0
NYMOX PHARMACEUTICAL CORP COM 67076p102 99 15,000 SH   SOLE   15,000 0 0
O REILLY AUTOMOTIVE INC COM 67103H107 15,495 121,441 SH   SOLE   121,441 0 0
ODYSSEY MARINE EXPLORATION COM 676118102 135 45,000 SH   SOLE   45,000 0 0
ONEBEACON INSURANCE GP COM G67742109 311 21,040 SH   SOLE   21,040 0 0
PAYCHEX COM 704326107 6,337 155,930 SH   SOLE   155,930 0 0
PEPSICO INC COM 713448108 365 4,594 SH   SOLE   4,594 0 0
PFIZER INC COM 717081103 1,212 42,182 SH   SOLE   42,182 0 0
PHILIP MORRIS INTL COM 718172109 457 5,275 SH   SOLE   5,275 0 0
PINNACLE WEST CAPITOL CORP COM 723484101 241 4,400 SH   SOLE   4,400 0 0
PNC FINANCIAL SVCS INC COM 693475105 1,905 26,290 SH   SOLE   26,290 0 0
POTASH CORP OF SASKATCHEWAN COM 73755L107 51,639 1,650,877 SH   SOLE   1,650,877 0 0
PRECISION CASTPARTS CORP COM 740189105 409 1,800 SH   SOLE   1,800 0 0
PRICE SMART INC COM 741511109 27,760 291,497 SH   SOLE   291,497 0 0
PROCTER & GAMBLE CO COM 742718109 22,979 303,993 SH   SOLE   303,993 0 0
QUALCOMM INC COM 747525103 126,209 1,874,759 SH   SOLE   1,874,759 0 0
QUANTA SERVICES INC COM 74762e102 2,580 93,772 SH   SOLE   93,772 0 0
RANGE RESOURCES CORP COM 75281A109 50,021 659,122 SH   SOLE   659,122 0 0
RAVEN INDUSTRIES, INC. COM 754212108 254 7,758 SH   SOLE   7,758 0 0
REALPAGE, INC. COM 75606n109 25,319 1,095,575 SH   SOLE   1,095,575 0 0
RED HAT INC. COM 756577102 96,270 2,086,468 SH   SOLE   2,086,468 0 0
RENAISSANCE RE HOLDINGS LTD COM G7496G103 588 6,490 SH   SOLE   6,490 0 0
RESMED INC COM 761152107 1,137 21,526 SH   SOLE   21,526 0 0
ROPER INDUSTRIES, INC COM 776696106 99,912 751,955 SH   SOLE   751,955 0 0
SBA COMMUNICATIONS CORP COM 78388J106 1,847 22,954 SH   SOLE   22,954 0 0
SCHLUMBERGER LTD COM 806857108 121,060 1,370,074 SH   SOLE   1,370,074 0 0
SEI INVESTMENTS CO COM 784117103 111,789 3,616,611 SH   SOLE   3,616,611 0 0
SILVER WHEATON CORP COM 828336107 483 19,500 SH   SOLE   19,500 0 0
SOTHERLY HOTELS, INC COM 55302L102 76 16,125 SH   SOLE   16,125 0 0
SOUTHWESTERN ENERGY CO COM 845467109 42,152 1,158,647 SH   SOLE   1,158,647 0 0
STERICYCLE INC COM 858912108 121,108 1,049,465 SH   SOLE   1,049,465 0 0
STONEMOR PARTNERS LP COM 86183Q100 284 12,000 SH   SOLE   12,000 0 0
STRYKER CORP COM 863667101 312 4,609 SH   SOLE   4,609 0 0
T ROWE PRICE GROUP INC COM 74144T108 91,267 1,268,830 SH   SOLE   1,268,830 0 0
TECHNE CORP COM 878377100 1,328 16,584 SH   SOLE   16,584 0 0
TELEFLEX INC COM 879369106 226 2,750 SH   SOLE   2,750 0 0
TRIMBLE NAVIGATION LTD COM 896239100 150,822 5,076,474 SH   SOLE   5,076,474 0 0
TYLER TECHNOLOGIES INC COM 902252105 51,088 584,068 SH   SOLE   584,068 0 0
U.S. BANCORP COM 902973304 1,155 31,567 SH   SOLE   31,567 0 0
UNDER ARMOUR, INC COM 904311107 318 4,000 SH   SOLE   4,000 0 0
UNITED TECHNOLOGIES CORP COM 913017109 407 3,776 SH   SOLE   3,776 0 0
VENTAS INC COM 92276f100 2,647 43,044 SH   SOLE   43,044 0 0
VERISK ANALYTICS COM 92345Y106 55,538 854,955 SH   SOLE   854,955 0 0
VERIZON COMMUNICATIONS COM 92343V104 247 5,285 SH   SOLE   5,285 0 0
VISA INC COM 92826C839 104,062 544,541 SH   SOLE   544,541 0 0
WAGEWORKS INC COM 930427109 87,389 1,732,190 SH   SOLE   1,732,190 0 0
WALT DISNEY CO COM 254687106 575 8,919 SH   SOLE   8,919 0 0
WASTE CONNECTIONS INC COM 941053100 94,924 2,090,375 SH   SOLE   2,090,375 0 0
WELLS FARGO & CO COM 949746101 292 7,055 SH   SOLE   7,055 0 0
WHOLE FOODS MARKET COM 966837106 924 15,800 SH   SOLE   15,800 0 0
WR BERKLEY CORP COM 084423102 3,689 86,078 SH   SOLE   86,078 0 0
VANGUARD DIVIDEND ETFS 921908844 712 10,225 SH   SOLE   10,225 0 0
VANGUARD FTSE ALL-WORLD EX-US ETFS 922042775 2,638 54,272 SH   SOLE   54,272 0 0
VANGUARD FTSE EMERGING MARKETS ETFS 922042858 519 12,925 SH   SOLE   12,925 0 0
VANGUARD HIGH DIVIDEND YIELD E ETFS 921946406 266 4,625 SH   SOLE   4,625 0 0
VANGUARD INDEX REIT ETF ETFS 922908553 369 5,580 SH   SOLE   5,580 0 0