Note 7 - Business Segment Information (Details) - Selected Financial Information on the Company’s Business Segments - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenue	$ 30,324,532	$ 28,123,508
Net interest income	20,597,522	17,782,217
Net income attributable to QCR Holdings, Inc.	6,373,489	4,177,889
Total assets	2,640,673,254	2,491,659,006	$ 2,593,198,275
Provision for loan/lease losses	2,072,985	1,710,456
Goodwill	3,222,688	3,222,688	3,222,688
Core deposit intangible	1,421,531	1,621,043	$ 1,471,409
Operating Segments [Member] | Wealth Management Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	2,234,292	2,343,438
Net income attributable to QCR Holdings, Inc.	447,770	459,330
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	6,859,775	5,616,443
Net interest income	(300,887)	(485,200)
Net income attributable to QCR Holdings, Inc.	6,373,488	4,177,889
Total assets	288,814,613	221,549,665
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	(6,919,935)	(5,705,028)
Net income attributable to QCR Holdings, Inc.	(6,831,981)	(5,608,906)
Total assets	(262,638,349)	(208,470,899)
Quad City Bank and Trust Company [Member] | Operating Segments [Member] | Commercial Banking Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	13,516,932	12,801,418
Net interest income	10,961,447	9,275,038
Net income attributable to QCR Holdings, Inc.	2,831,696	2,562,613
Total assets	1,361,607,041	1,268,168,825
Provision for loan/lease losses	1,222,985	882,456
Goodwill	3,222,688	3,222,688
Cedar Rapids Bank and Trust [Member] | Operating Segments [Member] | Commercial Banking Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	10,839,221	9,525,647
Net interest income	7,024,988	6,358,297
Net income attributable to QCR Holdings, Inc.	2,934,731	2,068,306
Total assets	885,858,279	855,417,474
Provision for loan/lease losses	550,000	600,000
Core deposit intangible	1,421,531	1,621,043
Rockford Bank and Trust [Member] | Operating Segments [Member] | Commercial Banking Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	3,794,247	3,541,590
Net interest income	2,911,974	2,634,082
Net income attributable to QCR Holdings, Inc.	617,785	518,657
Total assets	367,031,670	354,993,941
Provision for loan/lease losses	$ 300,000	$ 228,000