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
AAR Corp COM 000361105 10,131 275,370 SH   SOLE   275,370 0 0
Abbott Laboratories COM 002824100 209,411 2,490,019 SH   SOLE   1,853,412 0 636,607
Abbvie Inc COM 00287Y109 5,747 79,024 SH   SOLE   17,130 0 61,894
Accenture PLC Cl A COM G1151C101 220 1,191 SH   SOLE   0 0 1,191
Actuant Corp COM 00508X203 8,944 360,508 SH   SOLE   360,508 0 0
Adobe Inc. COM 00724F101 604 2,050 SH   SOLE   375 0 1,675
ALLETE, Inc. COM 018522300 5,927 71,233 SH   SOLE   38,965 0 32,268
Alliant Energy Corp. COM 018802108 276 5,618 SH   SOLE   0 0 5,618
Alphabet Inc Class A COM 02079K305 1,635 1,510 SH   SOLE   917 0 593
Alphabet Inc Class C COM 02079K107 318,053 294,246 SH   SOLE   250,566 0 43,680
Altria Group Inc COM 02209S103 208 4,392 SH   SOLE   667 0 3,725
Amazon Com Inc COM 023135106 1,138 601 SH   SOLE   121 0 480
Amcor Plc COM G0250X107 53,058 4,617,788 SH   SOLE   2,633,765 0 1,984,023
American Express COM 025816109 167,087 1,353,592 SH   SOLE   1,090,579 0 263,013
American Tower Cl A COM 03027X100 684 3,345 SH   SOLE   200 0 3,145
Ameriprise Financial COM 03076C106 338 2,331 SH   SOLE   1,620 0 711
Ametek Inc. COM 031100100 245 2,700 SH   SOLE   2,700 0 0
Amgen COM 031162100 1,618 8,780 SH   SOLE   4,734 0 4,046
ANSYS Inc COM 03662Q105 203 990 SH   SOLE   0 0 990
Apogee Enterprises, Inc COM 037598109 15,601 359,130 SH   SOLE   359,030 0 100
Apple Inc COM 037833100 7,363 37,200 SH   SOLE   15,805 0 21,395
Applied Materials Inc COM 038222105 336 7,477 SH   SOLE   0 0 7,477
Assoc Banc Corp COM 045487105 56,105 2,653,955 SH   SOLE   2,325,119 0 328,836
AT&T Inc COM 00206R102 1,463 43,670 SH   SOLE   13,293 0 30,377
Automatic Data Proc COM 053015103 835 5,052 SH   SOLE   3,952 0 1,100
Badger Meter Inc COM 056525108 49,507 829,401 SH   SOLE   597,583 0 231,818
Bank of America Corp COM 060505104 434 14,955 SH   SOLE   4,390 0 10,565
Baxter International COM 071813109 50,732 619,435 SH   SOLE   401,077 0 218,358
Becton Dickinson & Co COM 075887109 798 3,165 SH   SOLE   1,702 0 1,463
Berkshire Hathaway COM 084670108 3,502 11 SH   SOLE   1 0 10
Berkshire Hathaway B COM 084670702 4,774 22,396 SH   SOLE   2,618 0 19,778
Bio-Techne Corp COM 09073M104 222,698 1,068,146 SH   SOLE   858,678 0 209,468
Biogen Inc. COM 09062X103 240 1,025 SH   SOLE   0 0 1,025
Black Hills Corp COM 092113109 11,964 153,050 SH   SOLE   153,050 0 0
Boeing COM 097023105 1,514 4,160 SH   SOLE   1,965 0 2,195
BP PLC COM 055622104 863 20,694 SH   SOLE   9,062 0 11,632
Bristol-Myers Squibb COM 110122108 10,772 237,532 SH   SOLE   159,676 0 77,856
Cabot Microelectronics Corp COM 12709P103 7,274 66,080 SH   SOLE   66,080 0 0
Calyxt Inc COM 13173L107 2,474 198,261 SH   SOLE   198,261 0 0
Cardiovascular Sys Inc COM 141619106 4,176 97,282 SH   SOLE   97,282 0 0
Carrizo Oil & Gas, Inc. COM 144577103 5,978 596,650 SH   SOLE   596,650 0 0
Casey's General Stores COM 147528103 12,354 79,200 SH   SOLE   79,200 0 0
Catalent, Inc. COM 148806102 16,933 312,358 SH   SOLE   311,755 0 603
Caterpillar COM 149123101 959 7,040 SH   SOLE   200 0 6,840
Celgene Corp COM 151020104 265 2,870 SH   SOLE   0 0 2,870
Cerner Corp COM 156782104 206 2,810 SH   SOLE   1,000 0 1,810
CH Robinson Worldwide COM 12541W209 166,787 1,977,322 SH   SOLE   1,605,504 0 371,818
Charles Schwab COM 808513105 47,978 1,193,791 SH   SOLE   942,659 0 251,132
Chevron Corp COM 166764100 30,062 241,579 SH   SOLE   121,759 0 119,820
Cisco COM 17275R102 2,035 37,184 SH   SOLE   9,721 0 27,463
Clorox COM 189054109 232 1,513 SH   SOLE   1,513 0 0
Coca-Cola COM 191216100 1,458 28,642 SH   SOLE   10,500 0 18,142
Colgate-Palmolive COM 194162103 636 8,876 SH   SOLE   2,600 0 6,276
Comcast New Cl A COM 20030N101 318 7,517 SH   SOLE   2,349 0 5,168
ConocoPhillips COM 20825C104 6,458 105,861 SH   SOLE   23,201 0 82,660
Core Laboratories NV COM N22717107 19,999 382,541 SH   SOLE   310,131 0 72,410
CoreSite Realty Corp COM 21870Q105 126,512 1,098,484 SH   SOLE   949,767 0 148,717
Corning COM 219350105 74,070 2,228,998 SH   SOLE   1,855,659 0 373,339
Costco Wholesale COM 22160K105 904 3,422 SH   SOLE   900 0 2,522
Cray Inc COM 225223304 6,332 181,847 SH   SOLE   59,520 0 122,327
CSX Corporation COM 126408103 615 7,950 SH   SOLE   0 0 7,950
Cullen Frost Bankers COM 229899109 19,230 205,320 SH   SOLE   162,550 0 42,770
CyberOptics Corp COM 232517102 3,851 237,284 SH   SOLE   237,284 0 0
Deere & Co. COM 244199105 239 1,442 SH   SOLE   112 0 1,330
Deluxe Corp COM 248019101 1,917 47,150 SH   SOLE   39,026 0 8,124
Digi Int'l Inc. COM 253798102 7,994 630,420 SH   SOLE   627,820 0 2,600
Disney COM 254687106 250,241 1,792,042 SH   SOLE   1,453,688 0 338,354
Dominion Energy, Inc. COM 25746U109 358 4,632 SH   SOLE   1,250 0 3,382
Donaldson COM 257651109 254,342 5,000,831 SH   SOLE   4,016,947 0 983,884
Ecolab Inc COM 278865100 361,578 1,831,331 SH   SOLE   1,387,734 0 443,597
Edwards Lifesciences COM 28176E108 244 1,320 SH   SOLE   200 0 1,120
Elanco Animal Health Inc. COM 28414H103 20,904 618,474 SH   SOLE   415,699 0 202,775
EMC Insurance Group COM 268664109 3,254 90,305 SH   SOLE   90,305 0 0
Emerson Electric COM 291011104 26,876 402,820 SH   SOLE   195,857 0 206,963
Enterprise Prod Ptnrs LP COM 293792107 266 9,200 SH   SOLE   8,600 0 600
Exelon Corp COM 30161N101 404 8,428 SH   SOLE   0 0 8,428
Exxon Mobil COM 30231G102 27,396 357,513 SH   SOLE   150,188 0 207,325
Facebook Inc Class A COM 30303M102 251 1,300 SH   SOLE   1,234 0 66
Fastenal Co. COM 311900104 171,059 5,248,832 SH   SOLE   4,130,358 0 1,118,474
FireEye, Inc. COM 31816Q101 3,104 209,605 SH   SOLE   209,605 0 0
Fiserv COM 337738108 190,996 2,095,171 SH   SOLE   1,655,103 0 440,068
Fleetcor Technologies Inc COM 339041105 281 1,000 SH   SOLE   0 0 1,000
Generac Hldgs COM 368736104 47,602 685,815 SH   SOLE   610,092 0 75,723
General Electric COM 369604103 1,068 101,701 SH   SOLE   15,065 0 86,636
General Mills COM 370334104 126,006 2,399,195 SH   SOLE   1,729,867 0 669,328
Gentherm Inc COM 37253A103 21,889 523,275 SH   SOLE   480,903 0 42,372
Genuine Parts COM 372460105 202 1,950 SH   SOLE   1,700 0 250
Glacier Bancorp Inc COM 37637Q105 11,860 292,485 SH   SOLE   292,115 0 370
Graco Inc COM 384109104 257,655 5,134,621 SH   SOLE   3,913,725 0 1,220,897
Great Western Bancorp Inc. COM 391416104 82,972 2,322,836 SH   SOLE   2,021,340 0 301,496
Hawkins Chemical COM 420261109 3,991 91,937 SH   SOLE   85,437 0 6,500
HB Fuller COM 359694106 127,847 2,755,330 SH   SOLE   2,364,397 0 390,933
Heico Corp COM 422806109 227 1,700 SH   SOLE   1,200 0 500
Hershey COM 427866108 11,717 87,423 SH   SOLE   77,130 0 10,293
Home Depot COM 437076102 63,393 304,820 SH   SOLE   188,517 0 116,303
Honeywell Inc COM 438516106 226,742 1,298,713 SH   SOLE   909,379 0 389,334
Hormel COM 440452100 232,086 5,724,858 SH   SOLE   4,632,775 0 1,092,083
Hub Group Inc Cl A COM 443320106 12,006 285,995 SH   SOLE   285,995 0 0
IBM COM 459200101 5,424 39,335 SH   SOLE   27,061 0 12,274
IDEXX Laboratories, Inc COM 45168D104 936 3,398 SH   SOLE   400 0 2,998
Illinois Tool Works Inc COM 452308109 437 2,899 SH   SOLE   1,450 0 1,449
Inspire Medical Systems Inc COM 457730109 9,511 156,810 SH   SOLE   155,910 0 900
Intel COM 458140100 18,724 391,142 SH   SOLE   128,962 0 262,180
Intl Flavors/Fragr COM 459506101 358 2,466 SH   SOLE   2,466 0 0
Intricon Corp Com COM 46121H109 5,641 241,498 SH   SOLE   241,498 0 0
IPG Photonics Corp COM 44980X109 231 1,500 SH   SOLE   0 0 1,500
J.P. Morgan Chase & Co COM 46625H100 27,644 247,263 SH   SOLE   158,760 0 88,503
Johnson & Johnson COM 478160104 287,576 2,064,729 SH   SOLE   1,625,519 0 439,210
Kellogg COM 487836108 228 4,250 SH   SOLE   1,700 0 2,550
Kimberly-Clark COM 494368103 16,113 120,899 SH   SOLE   53,311 0 67,588
Lilly (Eli) COM 532457108 74,994 676,906 SH   SOLE   470,916 0 205,990
Littelfuse Inc. COM 537008104 81,999 463,507 SH   SOLE   385,932 0 77,575
Lockheed Martin Corp COM 539830109 220 606 SH   SOLE   170 0 436
Lowes Companies Inc COM 548661107 744 7,369 SH   SOLE   2,751 0 4,618
Marcus Corp. COM 566330106 6,680 202,658 SH   SOLE   202,658 0 0
MasterCard Inc COM 57636Q104 713 2,695 SH   SOLE   300 0 2,395
McCormick & Co COM 579780206 209 1,350 SH   SOLE   600 0 750
McDonald's Corp COM 580135101 3,075 14,806 SH   SOLE   11,187 0 3,619
MDU Resources Group COM 552690109 1,690 65,493 SH   SOLE   20,208 0 45,285
Medtronic COM G5960L103 300,649 3,087,062 SH   SOLE   2,439,210 0 647,852
Merck & Co Inc COM 58933Y105 6,574 78,405 SH   SOLE   24,129 0 54,276
MGP Ingredients Inc COM 55303J106 4,390 66,200 SH   SOLE   66,200 0 0
Microsoft COM 594918104 225,692 1,684,774 SH   SOLE   1,417,981 0 266,793
MMM Co. COM 88579Y101 324,132 1,869,922 SH   SOLE   1,408,229 0 461,693
Mondelez Intl Cl A COM 609207105 235 4,364 SH   SOLE   3,085 0 1,279
Motorola Solutions Inc COM 620076307 50,602 303,497 SH   SOLE   284,908 0 18,589
MTS Systems COM 553777103 1,816 31,025 SH   SOLE   9,100 0 21,925
Nestle S A Reg B ADR COM 641069406 253 2,450 SH   SOLE   1,550 0 900
NextEra Energy, Inc. COM 65339F101 339 1,656 SH   SOLE   472 0 1,184
Nike COM 654106103 369 4,400 SH   SOLE   1,450 0 2,950
Norfolk Southern Corp COM 655844108 869 4,360 SH   SOLE   0 0 4,360
Northrop Grumman Corp COM 666807102 233 720 SH   SOLE   500 0 220
Novartis COM 66987V109 265 2,900 SH   SOLE   700 0 2,200
NVE Corp COM 629445206 29,153 418,683 SH   SOLE   360,276 0 58,407
nVent Electric PLC COM G6700G107 61,572 2,483,743 SH   SOLE   1,989,420 0 494,323
NVIDIA Corp COM 67066G104 54,732 333,265 SH   SOLE   318,380 0 14,885
NW Biotherapeutics COM 66737P600 3 12,500 SH   SOLE   0 0 12,500
Oasis Petroleum Inc COM 674215108 5,194 914,455 SH   SOLE   914,455 0 0
Old Natl Bancorp Ind Com COM 680033107 81,575 4,917,112 SH   SOLE   4,404,672 0 512,440
Oracle Sys COM 68389X105 1,740 30,549 SH   SOLE   547 0 30,002
Orocobre Ltd COM Q7142R106 65 33,000 SH   SOLE   33,000 0 0
Oshkosh Corp COM 688239201 15,379 184,200 SH   SOLE   184,200 0 0
Otter Tail Power COM 689648103 201 3,800 SH   SOLE   0 0 3,800
Patterson Companies COM 703395103 13,788 602,094 SH   SOLE   444,158 0 157,936
Paychex COM 704326107 232 2,819 SH   SOLE   1,642 0 1,177
Pentair PLC COM G7S00T104 61,171 1,644,374 SH   SOLE   1,175,347 0 469,027
PepsiCo Inc COM 713448108 1,889 14,402 SH   SOLE   5,885 0 8,517
Pfizer Inc COM 717081103 121,998 2,816,195 SH   SOLE   2,131,977 0 684,218
Philip Morris Intl Inc COM 718172109 472 6,008 SH   SOLE   1,623 0 4,385
Phillips 66 COM 718546104 2,021 21,611 SH   SOLE   7,184 0 14,427
Physicians Realty Tr COM 71943U104 8,286 475,095 SH   SOLE   455,795 0 19,300
Plug Power Inc COM 72919P202 68 30,000 SH   SOLE   30,000 0 0
Polaris Ind COM 731068102 209 2,292 SH   SOLE   2,142 0 150
Polymet Mining Corp COM 731916102 60 140,000 SH   SOLE   140,000 0 0
Premier Inc Cl A COM 74051N102 10,791 275,909 SH   SOLE   275,909 0 0
Principal Financial COM 74251V102 168,032 2,901,102 SH   SOLE   2,377,194 0 523,908
Procter & Gamble COM 742718109 25,194 229,767 SH   SOLE   67,766 0 162,001
Proto Labs COM 743713109 26,937 232,179 SH   SOLE   184,103 0 48,076
PureCycle Corp COM 746228303 126 11,855 SH   SOLE   0 0 11,855
QCR Holdings COM 74727A104 4,388 125,830 SH   SOLE   125,830 0 0
Qualcomm, Inc. COM 747525103 96,282 1,265,699 SH   SOLE   1,096,866 0 168,833
Raven Industries Inc COM 754212108 8,409 234,371 SH   SOLE   233,871 0 500
Raytheon Co COM 755111507 239 1,375 SH   SOLE   0 0 1,375
Resideo Technologies COM 76118Y104 384 17,509 SH   SOLE   7,300 0 10,209
Roche Hldg Ltd ADR COM 771195104 188,215 5,362,258 SH   SOLE   4,652,767 0 709,491
Royal Dutch Shell Spons ADR A COM 780259206 332 5,095 SH   SOLE   400 0 4,695
Schlumberger COM 806857108 89,102 2,242,136 SH   SOLE   1,807,879 0 434,257
Sherwin Williams Co COM 824348106 24,461 53,374 SH   SOLE   44,220 0 9,154
Snap-On Inc. COM 833034101 16,279 98,281 SH   SOLE   37,027 0 61,254
Southern Co. COM 842587107 244 4,417 SH   SOLE   1,659 0 2,758
Starbucks Corp COM 855244109 786 9,375 SH   SOLE   9,245 0 130
Sysco COM 871829107 373 5,272 SH   SOLE   2,972 0 2,300
Target COM 87612E106 72,691 839,287 SH   SOLE   536,133 0 303,153
TCF Financial COM 872275102 733 35,276 SH   SOLE   17,744 0 17,532
Tennant Company COM 880345103 83,022 1,356,566 SH   SOLE   1,192,366 0 164,200
The Blackstone Inc. Cl A COM 09260D107 555 12,500 SH   SOLE   12,500 0 0
Thermo Fisher Scientific COM 883556102 605 2,060 SH   SOLE   600 0 1,460
Tile Shop Inc COM 88677Q109 3,299 824,865 SH   SOLE   824,865 0 0
Toro COM 891092108 185,775 2,776,902 SH   SOLE   2,252,138 0 524,764
Travelers Cos Inc COM 89417E109 35,359 236,486 SH   SOLE   108,876 0 127,610
Union Pacific COM 907818108 1,481 8,759 SH   SOLE   1,900 0 6,859
United Bankshares Inc. COM 909907107 4,145 111,759 SH   SOLE   111,759 0 0
United Fire Group COM 910340108 8,303 171,342 SH   SOLE   171,342 0 0
United Health Group COM 91324P102 171,878 704,389 SH   SOLE   606,940 0 97,449
United Parcel Service COM 911312106 94,157 911,752 SH   SOLE   668,701 0 243,051
United Technologies COM 913017109 1,854 14,236 SH   SOLE   5,063 0 9,173
US Bancorp COM 902973304 347,745 6,636,358 SH   SOLE   5,390,845 0 1,245,513
Verizon Comm COM 92343V104 6,623 115,932 SH   SOLE   23,106 0 92,826
Visa, Inc COM 92826C839 116,447 670,972 SH   SOLE   558,623 0 112,349
Walgreen Boots Alliance COM 931427108 544 9,950 SH   SOLE   2,500 0 7,450
Walmart Inc COM 931142103 508 4,596 SH   SOLE   1,700 0 2,896
WEC Energy Group COM 92939U106 614 7,369 SH   SOLE   0 0 7,369
Wells Fargo & Co COM 949746101 109,783 2,320,008 SH   SOLE   1,776,614 0 543,394
Westamerica Bancorporation COM 957090103 330 5,359 SH   SOLE   0 0 5,359
Western Union COM 959802109 716 36,009 SH   SOLE   5,700 0 30,309
Weyerhaeuser COM 962166104 468 17,758 SH   SOLE   5,299 0 12,459
Wintrust Finan Corp COM 97650W108 15,531 212,285 SH   SOLE   212,285 0 0
Workiva Inc COM 98139A105 6,839 117,733 SH   SOLE   117,733 0 0
Xcel Energy Inc. COM 98389B100 14,425 242,485 SH   SOLE   116,869 0 125,616
Zimmer Biomet Holdings COM 98956P102 121,010 1,027,772 SH   SOLE   822,486 0 205,286
Zoetis Inc. COM 98978V103 436 3,840 SH   SOLE   1,900 0 1,940
AMEX Technology SPDR ETF 81369Y803 215 2,752 SH   SOLE   1,052 0 1,700
iShares Core S&P 500 ETF ETF 464287200 1,316 4,464 SH   SOLE   135 0 4,329
iShares Core S&P Midcap ETF ETF 464287507 409 2,105 SH   SOLE   0 0 2,105
iShares MSCI EAFE Fd ETF 464287465 410 6,239 SH   SOLE   0 0 6,239
iShares Russell 1000 Growth ETF 464287614 1,030 6,545 SH   SOLE   0 0 6,545
iShares Russell 1000 Value ETF 464287598 512 4,025 SH   SOLE   25 0 4,000
iShares Russell 2000 ETF ETF 464287655 543 3,495 SH   SOLE   175 0 3,320
iShares Russell Midcap ETF ETF 464287499 718 12,860 SH   SOLE   0 0 12,860
iShares S&P Smallcap ETF 464287887 302 1,655 SH   SOLE   0 0 1,655
iShares Select Div ETF 464287168 598 6,005 SH   SOLE   46 0 5,959
Schwab Intl Eq ETF ETF 808524805 1,611 50,190 SH   SOLE   0 0 50,190
Schwab US Broad Mkt ETF ETF 808524102 3,200 45,370 SH   SOLE   11,560 0 33,810
SPDR S&P 500 ETF Trust ETF 78462F103 4,764 16,261 SH   SOLE   7,547 0 8,714
Vanguard Dividend App ETF ETF 921908844 369 3,204 SH   SOLE   959 0 2,245
Eaton Vance Muni Bond COM 27827X101 128 10,316 SH   SOLE   10,316 0 0
Nuveen MN Qual Mun Income Fd COM 670734102 507 37,002 SH   SOLE   5,802 0 31,200
Polymet Mining Corp RT RT 731916136 0 140,000 SH   SOLE   140,000 0 0