Note 8 - Regulatory Capital Requirements and Restrictions on Dividends (Details) - Capital Requirements - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital actual amount		$ 274,586	$ 204,376
Total risk-based capital actual ratio		13.06%	10.91%
Total risk-based capital for capital adequacy purposes amount		$ 168,246	$ 149,876
Total risk-based capital for capital adequacy purposes ratio		8.00%	8.00%
Total risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 210,308
Total risk-based capital to be well capitalized under prompt corrective action provisions ratio		10.00%
Total risk-based capital new Basel III minimums amount	[1]	$ 168,246
Total risk-based capital new Basel III minimums ratio	[1]	8.00%
Tier 1 risk-based capital actual amount		$ 248,802	$ 178,364
Tier 1 risk-based capital actual ratio		11.83%	9.52%
Tier 1 risk-based capital for capital adequacy purposes amount		$ 126,185	$ 74,938
Tier 1 risk-based capital for capital adequacy purposes ratio		6.00%	4.00%
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 168,246
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions ratio		8.00%
Tier 1 risk-based capital new Basel III minimums amount	[1]	$ 126,185
Tier 1 risk-based capital new Basel III minimums ratio	[1]	6.00%
Tier 1 leverage actual amount		$ 248,802	$ 178,364
Tier 1 leverage actual ratio		9.73%	7.62%
Tier 1 leverage for capital adequacy purposes amount		$ 102,260	$ 93,658
Tier 1 leverage for capital adequacy purposes ratio		4.00%	4.00%
Tier 1 leverage to be well capitalized under prompt corrective action provisions amount		$ 127,825
Tier 1 leverage to be well capitalized under prompt corrective action provisions ratio		5.00%
Tier 1 leverage new Basel III minimums amount	[1]	$ 102,260
Tier 1 leverage new Basel III minimums ratio	[1]	4.00%
Common equity Tier 1 actual amount		$ 213,710
Common equity Tier 1 actual ratio		10.16%
Common equity Tier 1 capital adequacy purposes amount		$ 94,638
Common equity Tier 1 capital adequacy purposes ratio		4.50%
Common equity Tier 1 to be well capitalized under prompt corrective action provisions amount		$ 136,700
Common equity Tier 1 to be well capitalized under prompt corrective action provisions ratio		6.50%
Common equity Tier 1 new Basel III minimums amount	[1]	$ 94,638
Common equity Tier 1 new Basel III minimums ratio	[1]	4.50%
Quad City Bank and Trust Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital actual amount		$ 131,695	$ 104,869
Total risk-based capital actual ratio		12.64%	11.26%
Total risk-based capital for capital adequacy purposes amount		$ 83,340	$ 74,495
Total risk-based capital for capital adequacy purposes ratio		8.00%	8.00%
Total risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 104,175	$ 93,119
Total risk-based capital to be well capitalized under prompt corrective action provisions ratio		10.00%	10.00%
Total risk-based capital new Basel III minimums amount	[1]	$ 83,340
Total risk-based capital new Basel III minimums ratio	[1]	8.00%
Tier 1 risk-based capital actual amount		$ 120,268	$ 93,785
Tier 1 risk-based capital actual ratio		11.54%	10.07%
Tier 1 risk-based capital for capital adequacy purposes amount		$ 62,505	$ 37,248
Tier 1 risk-based capital for capital adequacy purposes ratio		6.00%	4.00%
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 83,340	$ 55,872
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions ratio		8.00%	6.00%
Tier 1 risk-based capital new Basel III minimums amount	[1]	$ 62,505
Tier 1 risk-based capital new Basel III minimums ratio	[1]	6.00%
Tier 1 leverage actual amount		$ 120,268	$ 93,785
Tier 1 leverage actual ratio		8.97%	7.10%
Tier 1 leverage for capital adequacy purposes amount		$ 53,610	$ 52,817
Tier 1 leverage for capital adequacy purposes ratio		4.00%	4.00%
Tier 1 leverage to be well capitalized under prompt corrective action provisions amount		$ 67,012	$ 66,021
Tier 1 leverage to be well capitalized under prompt corrective action provisions ratio		5.00%	5.00%
Tier 1 leverage new Basel III minimums amount	[1]	$ 53,610
Tier 1 leverage new Basel III minimums ratio	[1]	4.00%
Common equity Tier 1 actual amount		$ 120,268
Common equity Tier 1 actual ratio		11.54%
Common equity Tier 1 capital adequacy purposes amount		$ 46,879
Common equity Tier 1 capital adequacy purposes ratio		4.50%
Common equity Tier 1 to be well capitalized under prompt corrective action provisions amount		$ 67,714
Common equity Tier 1 to be well capitalized under prompt corrective action provisions ratio		6.50%
Common equity Tier 1 new Basel III minimums amount	[1]	$ 46,879
Common equity Tier 1 new Basel III minimums ratio	[1]	4.50%
Cedar Rapids Bank and Trust [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital actual amount		$ 103,138	$ 76,662
Total risk-based capital actual ratio		13.81%	11.54%
Total risk-based capital for capital adequacy purposes amount		$ 59,755	$ 53,126
Total risk-based capital for capital adequacy purposes ratio		8.00%	8.00%
Total risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 74,694	$ 66,407
Total risk-based capital to be well capitalized under prompt corrective action provisions ratio		10.00%	10.00%
Total risk-based capital new Basel III minimums amount	[1]	$ 59,755
Total risk-based capital new Basel III minimums ratio	[1]	8.00%
Tier 1 risk-based capital actual amount		$ 93,784	$ 68,772
Tier 1 risk-based capital actual ratio		12.56%	10.36%
Tier 1 risk-based capital for capital adequacy purposes amount		$ 44,817	$ 26,563
Tier 1 risk-based capital for capital adequacy purposes ratio		6.00%	4.00%
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 59,755	$ 39,844
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions ratio		8.00%	6.00%
Tier 1 risk-based capital new Basel III minimums amount	[1]	$ 44,817
Tier 1 risk-based capital new Basel III minimums ratio	[1]	6.00%
Tier 1 leverage actual amount		$ 93,784	$ 68,772
Tier 1 leverage actual ratio		10.68%	8.21%
Tier 1 leverage for capital adequacy purposes amount		$ 35,121	$ 33,525
Tier 1 leverage for capital adequacy purposes ratio		4.00%	4.00%
Tier 1 leverage to be well capitalized under prompt corrective action provisions amount		$ 43,901	$ 41,906
Tier 1 leverage to be well capitalized under prompt corrective action provisions ratio		5.00%	5.00%
Tier 1 leverage new Basel III minimums amount	[1]	$ 35,121
Tier 1 leverage new Basel III minimums ratio	[1]	4.00%
Common equity Tier 1 actual amount		$ 93,784
Common equity Tier 1 actual ratio		12.56%
Common equity Tier 1 capital adequacy purposes amount		$ 33,612
Common equity Tier 1 capital adequacy purposes ratio		4.50%
Common equity Tier 1 to be well capitalized under prompt corrective action provisions amount		$ 48,551
Common equity Tier 1 to be well capitalized under prompt corrective action provisions ratio		6.50%
Common equity Tier 1 new Basel III minimums amount	[1]	$ 33,612
Common equity Tier 1 new Basel III minimums ratio	[1]	4.50%
Rockford Bank and Trust [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital actual amount		$ 38,827	$ 35,906
Total risk-based capital actual ratio		12.40%	12.56%
Total risk-based capital for capital adequacy purposes amount		$ 25,047	$ 22,875
Total risk-based capital for capital adequacy purposes ratio		8.00%	8.00%
Total risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 31,308	$ 28,594
Total risk-based capital to be well capitalized under prompt corrective action provisions ratio		10.00%	10.00%
Total risk-based capital new Basel III minimums amount	[1]	$ 25,047
Total risk-based capital new Basel III minimums ratio	[1]	8.00%
Tier 1 risk-based capital actual amount		$ 34,909	$ 32,325
Tier 1 risk-based capital actual ratio		11.15%	11.30%
Tier 1 risk-based capital for capital adequacy purposes amount		$ 18,785	$ 11,438
Tier 1 risk-based capital for capital adequacy purposes ratio		6.00%	4.00%
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions amount		$ 25,047	$ 17,156
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions ratio		8.00%	6.00%
Tier 1 risk-based capital new Basel III minimums amount	[1]	$ 18,785
Tier 1 risk-based capital new Basel III minimums ratio	[1]	6.00%
Tier 1 leverage actual amount		$ 34,909	$ 32,325
Tier 1 leverage actual ratio		9.63%	9.16%
Tier 1 leverage for capital adequacy purposes amount		$ 14,495	$ 14,112
Tier 1 leverage for capital adequacy purposes ratio		4.00%	4.00%
Tier 1 leverage to be well capitalized under prompt corrective action provisions amount		$ 18,119	$ 17,640
Tier 1 leverage to be well capitalized under prompt corrective action provisions ratio		5.00%	5.00%
Tier 1 leverage new Basel III minimums amount	[1]	$ 14,495
Tier 1 leverage new Basel III minimums ratio	[1]	4.00%
Common equity Tier 1 actual amount		$ 34,909
Common equity Tier 1 actual ratio		11.15%
Common equity Tier 1 capital adequacy purposes amount		$ 14,089
Common equity Tier 1 capital adequacy purposes ratio		4.50%
Common equity Tier 1 to be well capitalized under prompt corrective action provisions amount		$ 20,350
Common equity Tier 1 to be well capitalized under prompt corrective action provisions ratio		6.50%
Common equity Tier 1 new Basel III minimums amount	[1]	$ 14,089
Common equity Tier 1 new Basel III minimums ratio	[1]	4.50%

[1] The minimums under Basel III phase in higher by .625% (the capital conservation buffer) annually until 2019. The fully phased-in minimums are 10.5% (Total risk-based capital), 8.5% (Tier 1 risk-based capital), and 7.0% (Common equity Tier 1).