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
HEICO CORP NEW CL A CL A 422806208 57,685 686,236 SH   SOLE   686,236 0 0
AMETEK INC NEW COM COM 031100100 31,902 384,503 SH   SOLE   384,503 0 0
HEXCEL CORP NEW COM COM 428291108 27,478 397,306 SH   SOLE   397,306 0 0
RLI CORP COM COM 749607107 24,833 346,104 SH   SOLE   346,104 0 0
KAR AUCTION SVCS INC COM COM 48238T109 24,713 481,633 SH   SOLE   481,633 0 0
CANADIAN PAC RY LTD COM COM 13645T100 23,482 113,975 SH   SOLE   113,975 0 0
LINDE PLC COM COM G5494J103 23,385 132,925 SH   SOLE   132,925 0 0
ARCH CAP GROUP LTD ORD ORD G0450A105 22,268 689,000 SH   SOLE   689,000 0 0
INTERCONTINENTAL EXCHANGE INC COM 45866F104 22,246 292,170 SH   SOLE   292,170 0 0
RBC BEARINGS INC COM COM 75524B104 22,096 173,751 SH   SOLE   173,751 0 0
IDEX CORP COM COM 45167R104 21,860 144,061 SH   SOLE   144,061 0 0
LEGACY TEX FINL GROUP INC COM COM 52471Y106 21,817 583,500 SH   SOLE   583,500 0 0
M & T BK CORP COM COM 55261F104 20,209 128,705 SH   SOLE   128,705 0 0
TELEDYNE TECHNOLOGIES INC COM COM 879360105 19,733 83,256 SH   SOLE   83,256 0 0
TE CONNECTIVITY LTD REG SHS REG SHS H84989104 18,609 230,453 SH   SOLE   230,453 0 0
DORMAN PRODUCTS INC COM COM 258278100 18,529 210,345 SH   SOLE   210,345 0 0
BOOKING HLDGS INC COM COM 09857L108 18,060 10,350 SH   SOLE   10,350 0 0
BERKSHIRE HATHAWAY CLASS B CL B NEW 084670702 17,925 89,227 SH   SOLE   89,227 0 0
ROPER TECHNOLOGIES INC COM COM 776696106 17,812 52,086 SH   SOLE   52,086 0 0
ISHARES TR SELECT DIVID ETF SELECT DIVID ETF 464287168 17,674 180,021 SH   SOLE   180,021 0 0
MASTERCARD INC CL A CL A 57636Q104 15,899 67,524 SH   SOLE   67,524 0 0
O REILLY AUTOMOTIVE INC NEW CO COM 67103H107 15,701 40,434 SH   SOLE   40,434 0 0
COPART INC COM COM 217204106 15,626 257,893 SH   SOLE   257,893 0 0
INVESCO EXCHANGE TRADED FD TR S&P500 EQL WGT 46137V357 15,568 149,059 SH   SOLE   149,059 0 0
INGREDION INC COM COM 457187102 14,663 154,855 SH   SOLE   154,855 0 0
AMPHENOL CORP NEW CL A CL A 032095101 14,282 151,225 SH   SOLE   151,225 0 0
VISA INC COM CL A COM CL A 92826C839 12,446 79,684 SH   SOLE   79,684 0 0
HINGHAM INSTN SVGS MASS COM COM 433323102 12,206 70,959 SH   SOLE   70,959 0 0
ANHEUSER BUSCH INBEV SA/NV SPO SPONSORED ADR 03524A108 11,947 142,278 SH   SOLE   142,278 0 0
GRACO INC COM COM 384109104 10,633 214,715 SH   SOLE   214,715 0 0
NEWMARKET CORP COM COM 651587107 10,204 23,535 SH   SOLE   23,535 0 0
HENRY SCHEIN INC COM COM 806407102 9,563 159,099 SH   SOLE   159,099 0 0
WHITE MTNS INS GROUP LTD COM COM G9618E107 8,496 9,180 SH   SOLE   9,180 0 0
SPDR S&P 500 ETF TR TR UNIT TR UNIT 78462F103 8,209 29,059 SH   SOLE   29,059 0 0
APPLE INC COM COM 037833100 6,930 36,485 SH   SOLE   36,485 0 0
EQUITY COMWLTH COM SH BEN INT COM SH BEN INT 294628102 6,715 205,400 SH   SOLE   205,400 0 0
LCI INDS COM COM 50189K103 6,641 86,453 SH   SOLE   86,453 0 0
ISHARES TR RUS MDCP VAL ETF RUS MDCP VAL ETF 464287473 6,313 72,678 SH   SOLE   72,678 0 0
MICROSOFT CORP COM COM 594918104 6,197 52,544 SH   SOLE   52,544 0 0
COLGATE PALMOLIVE CO COM COM 194162103 6,099 88,985 SH   SOLE   88,985 0 0
WINMARK CORP COM COM 974250102 5,621 29,804 SH   SOLE   29,804 0 0
JPMORGAN CHASE & CO COM COM 46625H100 5,461 53,944 SH   SOLE   53,944 0 0
ENTEGRIS INC COM COM 29362U104 4,868 136,400 SH   SOLE   136,400 0 0
PAYPAL HLDGS INC COM COM 70450Y103 2,919 28,114 SH   SOLE   28,114 0 0
TEXAS INSTRS INC COM COM 882508104 2,685 25,310 SH   SOLE   25,310 0 0
ALPHABET INC CAP STK CL A CAP STK CL A 02079K305 2,623 2,229 SH   SOLE   2,229 0 0
SCHWAB STRATEGIC TR INTL EQTY INTL EQTY ETF 808524805 2,502 79,900 SH   SOLE   79,900 0 0
INTEL CORP COM COM 458140100 2,475 46,098 SH   SOLE   46,098 0 0
MOHAWK INDS INC COM COM 608190104 2,210 17,520 SH   SOLE   17,520 0 0
AMAZON COM INC COM COM 023135106 1,984 1,114 SH   SOLE   1,114 0 0
JOHNSON & JOHNSON COM COM 478160104 1,933 13,830 SH   SOLE   13,830 0 0
STARBUCKS CORP COM COM 855244109 1,612 21,685 SH   SOLE   21,685 0 0
CASS INFORMATION SYS INC COM COM 14808P109 1,591 33,635 SH   SOLE   33,635 0 0
COMCAST CORP NEW CL A CL A 20030N101 1,542 38,572 SH   SOLE   38,572 0 0
UTAH MED PRODS INC COM COM 917488108 1,497 16,964 SH   SOLE   16,964 0 0
CAMBRIDGE BANCORP COM COM 132152109 1,429 17,246 SH   SOLE   17,246 0 0
ISHARES TR CORE S&P SCP ETF CORE S&P SCP ETF 464287804 1,352 17,523 SH   SOLE   17,523 0 0
PETROLEO BRASILEIRO SA PETROBR SP ADR NON VTG 71654V101 1,311 91,657 SH   SOLE   91,657 0 0
FRP HLDGS INC COM COM 30292L107 1,253 26,347 SH   SOLE   26,347 0 0
MERCK & CO INC COM COM 58933Y105 1,164 13,993 SH   SOLE   13,993 0 0
NVE CORP COM NEW COM NEW 629445206 963 9,839 SH   SOLE   9,839 0 0
DIAGEO P L C SPON ADR NEW SPON ADR NEW 25243Q205 938 5,732 SH   SOLE   5,732 0 0
ALPHABET INC CAP STK CL C CAP STK CL C 02079K107 916 781 SH   SOLE   781 0 0
UNITED TECHNOLOGIES CORP COM COM 913017109 854 6,625 SH   SOLE   6,625 0 0
3M CO COM COM 88579Y101 794 3,820 SH   SOLE   3,820 0 0
AMERICAN EXPRESS CO COM COM 025816109 785 7,181 SH   SOLE   7,181 0 0
ANGIODYNAMICS INC COM COM 03475V101 757 33,105 SH   SOLE   33,105 0 0
ABBOTT LABS COM COM 002824100 743 9,291 SH   SOLE   9,291 0 0
ILLINOIS TOOL WKS INC COM COM 452308109 743 5,178 SH   SOLE   5,178 0 0
INTERNATIONAL BUSINESS MACHS C COM 459200101 715 5,066 SH   SOLE   5,066 0 0
DOWDUPONT INC COM COM 26078J100 710 13,322 SH   SOLE   13,322 0 0
DIAMOND HILL INVESTMENT GROUP COM NEW 25264R207 709 5,063 SH   SOLE   5,063 0 0
NOVARTIS A G SPONSORED ADR SPONSORED ADR 66987V109 695 7,233 SH   SOLE   7,233 0 0
ENSTAR GROUP LIMITED SHS SHS G3075P101 691 3,970 SH   SOLE   3,970 0 0
PFIZER INC COM COM 717081103 655 15,416 SH   SOLE   15,416 0 0
VANGUARD TAX MANAGED INTL FD F FTSE DEV MKT ETF 921943858 627 15,345 SH   SOLE   15,345 0 0
TEXAS PAC LD TR SUB CTF PROP I SUB CTF PROP I T 882610108 603 780 SH   SOLE   780 0 0
CHASE CORP COM COM 16150R104 595 6,428 SH   SOLE   6,428 0 0
TD AMERITRADE HLDG CORP COM COM 87236Y108 583 11,656 SH   SOLE   11,656 0 0
MCDONALDS CORP COM COM 580135101 541 2,848 SH   SOLE   2,848 0 0
ISHARES GOLD TRUST ISHARES ISHARES 464285105 529 42,700 SH   SOLE   42,700 0 0
ENTERPRISE PRODS PARTNERS L P COM 293792107 508 17,450 SH   SOLE   17,450 0 0
NORTHERN TR CORP COM COM 665859104 507 5,604 SH   SOLE   5,604 0 0
VANGUARD INDEX FDS TOTAL STK M TOTAL STK MKT 922908769 504 3,485 SH   SOLE   3,485 0 0
UNILEVER N V N Y SHS NEW N Y SHS NEW 904784709 495 8,500 SH   SOLE   8,500 0 0
ZIX CORP COM COM 98974P100 486 70,694 SH   SOLE   70,694 0 0
MONDELEZ INTL INC CL A CL A 609207105 465 9,312 SH   SOLE   9,312 0 0
PETROLEO BRASILEIRO SA PETROBR SPONSORED ADR 71654V408 449 28,233 SH   SOLE   28,233 0 0
CSW INDUSTRIALS INC COM COM 126402106 447 7,800 SH   SOLE   7,800 0 0
CONOCOPHILLIPS COM COM 20825C104 441 6,608 SH   SOLE   6,608 0 0
WELLS FARGO CO NEW COM COM 949746101 422 8,731 SH   SOLE   8,731 0 0
EXXON MOBIL CORP COM COM 30231G102 420 5,195 SH   SOLE   5,195 0 0
UNITEDHEALTH GROUP INC COM COM 91324P102 406 1,641 SH   SOLE   1,641 0 0
EATON CORP PLC SHS SHS G29183103 400 4,963 SH   SOLE   4,963 0 0
UNILEVER PLC SPON ADR NEW SPON ADR NEW 904767704 396 6,864 SH   SOLE   6,864 0 0
BANK AMER CORP COM COM 060505104 388 14,064 SH   SOLE   14,064 0 0
NIKE INC CL B CL B 654106103 375 4,456 SH   SOLE   4,456 0 0
VANGUARD WHITEHALL FDS INC HIG HIGH DIV YLD 921946406 363 4,235 SH   SOLE   4,235 0 0
TWITTER INC COM COM 90184L102 362 11,019 SH   SOLE   11,019 0 0
FACEBOOK INC CL A CL A 30303M102 357 2,141 SH   SOLE   2,141 0 0
BROWN FORMAN CORP CL B CL B 115637209 354 6,707 SH   SOLE   6,707 0 0
ONEOK INC NEW COM COM 682680103 341 4,882 SH   SOLE   4,882 0 0
FEDEX CORP COM COM 31428X106 338 1,863 SH   SOLE   1,863 0 0
MARTIN MARIETTA MATLS INC COM COM 573284106 335 1,666 SH   SOLE   1,666 0 0
BANK NEW YORK MELLON CORP COM COM 064058100 333 6,594 SH   SOLE   6,594 0 0
WILLIAMS COS INC DEL COM COM 969457100 322 11,224 SH   SOLE   11,224 0 0
BECTON DICKINSON & CO COM COM 075887109 322 1,288 SH   SOLE   1,288 0 0
ROYAL DUTCH SHELL PLC SPONS AD SPONS ADR A 780259206 294 4,700 SH   SOLE   4,700 0 0
ISHARES TR MSCI ACWI ETF MSCI ACWI ETF 464288257 289 4,000 SH   SOLE   4,000 0 0
DUKE ENERGY CORP NEW COM NEW COM NEW 26441C204 280 3,111 SH   SOLE   3,111 0 0
ISHARES TR RUS 1000 VAL ETF RUS 1000 VAL ETF 464287598 269 2,176 SH   SOLE   2,176 0 0
AFLAC INC COM COM 001055102 255 5,101 SH   SOLE   5,101 0 0
PHILLIPS 66 PARTNERS LP COM UN COM UNIT REP INT 718549207 241 4,612 SH   SOLE   4,612 0 0
CHARTER COMMUNICATIONS INC NEW CL A 16119P108 239 690 SH   SOLE   690 0 0
ALTRIA GROUP INC COM COM 02209S103 232 4,034 SH   SOLE   4,034 0 0
PHILLIPS 66 COM COM 718546104 229 2,408 SH   SOLE   2,408 0 0
BADGER METER INC COM COM 056525108 223 4,000 SH   SOLE   4,000 0 0
MPLX LP COM UNIT REP LTD COM UNIT REP LTD 55336V100 217 6,600 SH   SOLE   6,600 0 0
HONEYWELL INTL INC COM COM 438516106 217 1,363 SH   SOLE   1,363 0 0
TARGA RES CORP COM COM 87612G101 213 5,134 SH   SOLE   5,134 0 0
DBX ETF TR XTRACK MSCI EURP XTRACK MSCI EURP 233051853 212 7,475 SH   SOLE   7,475 0 0
GRAHAM HLDGS CO COM COM 384637104 205 300 SH   SOLE   300 0 0
ACCENTURE PLC IRELAND SHS CLAS SHS CLASS A G1151C101 202 1,147 SH   SOLE   1,147 0 0
ENERGY TRANSFER LP COM UT LTD COM UT LTD PTN 29273V100 185 12,060 SH   SOLE   12,060 0 0
ENLINK MIDSTREAM LLC COM UNIT COM UNIT REP LTD 29336T100 151 11,788 SH   SOLE   11,788 0 0
PERMIAN BASIN RTY TR UNIT BEN UNIT BEN INT 714236106 79 10,500 SH   SOLE   10,500 0 0