NOTE 8 - BUSINESS SEGMENT INFORMATION - Selected Financial Information on the Company's Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Total revenue	$ 64,095	$ 48,087
Net interest income	36,908	32,403
Provision	2,134	2,540
Net income	12,918	10,550
Goodwill	77,872	28,334	$ 77,832
Core deposit intangible	16,918	8,774	17,450
Total assets	5,066,662	4,026,314	$ 4,949,710
Net income (loss)	12,918	10,550
Intersegment Eliminations [Member]
Total revenue	(14,658)	(12,600)
Net income	(14,450)	(12,420)
Total assets	(601,432)	(444,407)
Commercial Banking Segment [Member] | Quad City Bank and Trust Company [Member] | Operating Segments [Member]
Total revenue	18,544	15,808
Net interest income	12,139	12,120
Provision	1,020	1,120
Net income	4,185	4,458
Goodwill	3,223	3,223
Total assets	1,660,374	1,526,829
Commercial Banking Segment [Member] | Cedar Rapids Bank and Trust [Member] | Operating Segments [Member]
Total revenue	19,244	15,997
Net interest income	10,407	10,836
Provision	425	602
Net income	5,100	4,617
Goodwill	14,980	15,223
Core deposit intangible	3,061	3,567
Total assets	1,446,637	1,331,209
Commercial Banking Segment [Member] | Community State Bank [Member] | Operating Segments [Member]
Total revenue	9,270	8,163
Net interest income	6,966	6,744
Provision	150	576
Net income	2,157	1,869
Goodwill	9,888	9,888
Core deposit intangible	4,501	5,207
Total assets	785,076	696,979
Commercial Banking Segment [Member] | Rockford Bank and Trust [Member] | Operating Segments [Member]
Total revenue	5,596	4,998
Net interest income	3,428	3,465
Provision	39	242
Net income	517	741
Total assets	513,045	468,112
Commercial Banking Segment [Member] | SPRINGFIELD BANCSHARES, INC | Operating Segments [Member]
Total revenue	7,288
Net interest income	5,227
Provision	500
Net income	1,653
Goodwill	45,975
Core deposit intangible	7,501
Total assets	638,542
Wealth Management Segment [Member] | Operating Segments [Member]
Total revenue	4,229	3,189
Net income	1,158	771
Other Segments [Member] | Operating Segments [Member]
Total revenue	14,582	12,533
Net interest income	(1,259)	(762)
Net income	12,598	10,514
Goodwill	3,806
Core deposit intangible	1,855
Total assets	$ 624,420	$ 447,592