Regulatory Capital Requirements and Restrictions on Subsidiary Dividends (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 1,200,947	$ 1,010,116
Actual - Ratio	13.72%	13.45%
For Capital Adequacy Purposes - Amount	$ 700,490	$ 600,924
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 1,064,669	$ 879,133
Actual - Ratio	12.16%	11.70%
For Capital Adequacy Purposes - Amount	$ 525,368	$ 450,693
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 933,755	$ 756,309
Actual - Ratio	10.66%	10.07%
For Capital Adequacy Purposes - Amount	$ 394,026	$ 338,019
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 1,064,669	$ 879,133
Actual - Ratio	9.73%	9.20%
For Capital Adequacy Purposes - Amount	$ 437,858	$ 382,089
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
Minimum Capital Requirement
Tier 1 Capital (to Average Assets)
Retained earnings available for dividend payments	$ 486,500
Capital Requirement to Remain Well Capitalized
Tier 1 Capital (to Average Assets)
Retained earnings available for dividend payments	311,300
Dubuque Bank and Trust Company
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 165,687	$ 156,544
Actual - Ratio	14.10%	13.63%
For Capital Adequacy Purposes - Amount	$ 93,975	$ 91,878
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 117,469	$ 114,848
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 155,391	$ 148,080
Actual - Ratio	13.23%	12.89%
For Capital Adequacy Purposes - Amount	$ 70,482	$ 68,909
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 93,975	$ 91,878
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 155,391	$ 148,080
Actual - Ratio	13.23%	12.89%
For Capital Adequacy Purposes - Amount	$ 52,861	$ 51,681
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 76,355	$ 74,651
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 155,391	$ 148,080
Actual - Ratio	9.97%	10.05%
For Capital Adequacy Purposes - Amount	$ 62,317	$ 58,932
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 77,897	$ 73,666
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Illinois Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 74,657	$ 71,410
Actual - Ratio	13.02%	12.62%
For Capital Adequacy Purposes - Amount	$ 45,884	$ 45,265
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 57,355	$ 56,582
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 70,470	$ 66,547
Actual - Ratio	12.29%	11.76%
For Capital Adequacy Purposes - Amount	$ 34,413	$ 33,949
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 45,884	$ 45,265
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 70,470	$ 66,547
Actual - Ratio	12.29%	11.76%
For Capital Adequacy Purposes - Amount	$ 25,810	$ 25,462
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 37,281	$ 36,778
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 70,470	$ 66,547
Actual - Ratio	8.56%	8.39%
For Capital Adequacy Purposes - Amount	$ 32,941	$ 31,728
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 41,177	$ 39,660
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Wisconsin Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 115,318	$ 113,045
Actual - Ratio	13.90%	14.57%
For Capital Adequacy Purposes - Amount	$ 66,351	$ 62,057
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 82,939	$ 77,572
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 108,193	$ 106,236
Actual - Ratio	13.04%	13.70%
For Capital Adequacy Purposes - Amount	$ 49,763	$ 46,543
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 66,351	$ 62,057
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 108,193	$ 106,236
Actual - Ratio	13.04%	13.70%
For Capital Adequacy Purposes - Amount	$ 37,323	$ 34,907
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 53,910	$ 50,422
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 108,193	$ 106,236
Actual - Ratio	10.47%	10.53%
For Capital Adequacy Purposes - Amount	$ 41,317	$ 40,373
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 51,647	$ 50,466
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
New Mexico Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 150,261	$ 133,274
Actual - Ratio	12.92%	11.42%
For Capital Adequacy Purposes - Amount	$ 93,063	$ 93,401
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 116,328	$ 116,751
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 141,161	$ 123,519
Actual - Ratio	12.13%	10.58%
For Capital Adequacy Purposes - Amount	$ 69,797	$ 70,050
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 93,063	$ 93,401
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 141,161	$ 123,519
Actual - Ratio	12.13%	10.58%
For Capital Adequacy Purposes - Amount	$ 52,348	$ 52,538
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 75,613	$ 75,888
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 141,161	$ 123,519
Actual - Ratio	9.58%	8.54%
For Capital Adequacy Purposes - Amount	$ 58,958	$ 57,834
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 73,697	$ 72,292
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Arizona Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 63,606	$ 61,550
Actual - Ratio	11.90%	13.39%
For Capital Adequacy Purposes - Amount	$ 42,766	$ 36,773
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 53,458	$ 45,966
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 59,993	$ 56,870
Actual - Ratio	11.22%	12.37%
For Capital Adequacy Purposes - Amount	$ 32,075	$ 27,579
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 42,766	$ 36,773
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 59,993	$ 56,870
Actual - Ratio	11.22%	12.37%
For Capital Adequacy Purposes - Amount	$ 24,056	$ 20,685
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 34,748	$ 29,878
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 59,993	$ 56,870
Actual - Ratio	9.20%	9.94%
For Capital Adequacy Purposes - Amount	$ 26,089	$ 22,890
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 32,611	$ 28,613
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Rocky Mountain Bank
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 51,982	$ 50,729
Actual - Ratio	14.26%	13.78%
For Capital Adequacy Purposes - Amount	$ 29,160	$ 29,461
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 36,449	$ 36,826
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 48,428	$ 47,660
Actual - Ratio	13.29%	12.94%
For Capital Adequacy Purposes - Amount	$ 21,870	$ 22,096
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 29,160	$ 29,461
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 48,428	$ 47,660
Actual - Ratio	13.29%	12.94%
For Capital Adequacy Purposes - Amount	$ 16,402	$ 16,572
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 23,692	$ 23,937
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 48,428	$ 47,660
Actual - Ratio	9.82%	9.82%
For Capital Adequacy Purposes - Amount	$ 19,730	$ 19,418
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 24,662	$ 24,272
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Citywide Banks
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 235,691	$ 226,493
Actual - Ratio	13.46%	13.63%
For Capital Adequacy Purposes - Amount	$ 140,117	$ 132,975
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 175,146	$ 166,219
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 226,645	$ 221,239
Actual - Ratio	12.94%	13.31%
For Capital Adequacy Purposes - Amount	$ 105,088	$ 99,731
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 140,117	$ 132,975
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 226,645	$ 221,239
Actual - Ratio	12.94%	13.31%
For Capital Adequacy Purposes - Amount	$ 78,816	$ 74,799
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 113,845	$ 108,042
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 226,645	$ 221,239
Actual - Ratio	10.53%	10.03%
For Capital Adequacy Purposes - Amount	$ 86,129	$ 88,240
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 107,662	$ 110,300
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Minnesota Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 69,002	$ 23,760
Actual - Ratio	12.99%	13.76%
For Capital Adequacy Purposes - Amount	$ 42,493	$ 13,811
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 53,117	$ 17,264
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 63,633	$ 22,554
Actual - Ratio	11.98%	13.06%
For Capital Adequacy Purposes - Amount	$ 31,870	$ 10,358
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 42,493	$ 13,811
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 63,633	$ 22,554
Actual - Ratio	11.98%	13.06%
For Capital Adequacy Purposes - Amount	$ 23,903	$ 7,769
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 34,526	$ 11,222
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 63,633	$ 22,554
Actual - Ratio	10.00%	10.77%
For Capital Adequacy Purposes - Amount	$ 25,445	$ 8,379
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 31,806	$ 10,473
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Morrill & Janes Bank and Trust Company
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 72,520	$ 72,471
Actual - Ratio	16.14%	13.42%
For Capital Adequacy Purposes - Amount	$ 35,937	$ 43,206
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 44,922	$ 54,007
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 67,975	$ 67,328
Actual - Ratio	15.13%	12.47%
For Capital Adequacy Purposes - Amount	$ 26,953	$ 32,404
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 35,937	$ 43,206
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 67,975	$ 67,328
Actual - Ratio	15.13%	12.47%
For Capital Adequacy Purposes - Amount	$ 20,215	$ 24,303
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 29,199	$ 35,104
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 67,975	$ 67,328
Actual - Ratio	11.31%	9.47%
For Capital Adequacy Purposes - Amount	$ 24,041	$ 28,435
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 30,052	$ 35,543
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
Premier Valley Bank
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 85,710	$ 83,772
Actual - Ratio	13.71%	12.95%
For Capital Adequacy Purposes - Amount	$ 50,017	$ 51,743
For Capital Adequacy Purposes - Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 62,521	$ 64,679
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 82,321	$ 81,213
Actual - Ratio	13.17%	12.56%
For Capital Adequacy Purposes - Amount	$ 37,513	$ 38,808
For Capital Adequacy Purposes - Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 50,017	$ 51,743
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 82,321	$ 81,213
Actual - Ratio	13.17%	12.56%
For Capital Adequacy Purposes - Amount	$ 28,134	$ 29,106
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 40,639	$ 42,042
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 82,321	$ 81,213
Actual - Ratio	10.53%	9.80%
For Capital Adequacy Purposes - Amount	$ 31,285	$ 33,157
For Capital Adequacy Purposes - Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 39,106	$ 41,446
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%	5.00%
First Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 102,795
Actual - Ratio	13.48%
For Capital Adequacy Purposes - Amount	$ 61,004
For Capital Adequacy Purposes - Ratio	8.00%
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 76,255
To Be Well Capitalized Under Prompt Corrective Action - Ratio	10.00%
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 100,884
Actual - Ratio	13.23%
For Capital Adequacy Purposes - Amount	$ 45,753
For Capital Adequacy Purposes - Ratio	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 61,004
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	8.00%
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 100,884
Actual - Ratio	13.23%
For Capital Adequacy Purposes - Amount	$ 34,315
For Capital Adequacy Purposes - Ratio	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 49,566
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 100,884
Actual - Ratio	10.13%
For Capital Adequacy Purposes - Amount	$ 39,846
For Capital Adequacy Purposes - Ratio	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 49,807
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	5.00%