Note 5 - Business Segment Information (Detail) - Selected Financial Information on the Company’s Business Segments (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Net interest income	$ 14,515,493	$ 13,951,055	$ 28,718,946	$ 26,159,857
Net income attributable to QCR Holdings, Inc.	3,072,156	2,674,969	6,308,974	4,799,929
Total assets	2,043,425,746		2,043,425,746		1,966,610,054
Provision for loan/lease losses			1,828,915	2,739,885
Goodwill	3,222,688		3,222,688		3,222,688
Quad City Bank and Trust [Member]
Total revenue	11,936,569	11,887,135	24,201,602	23,842,944
Net interest income	8,532,585	7,831,907	16,921,627	14,828,267
Net income attributable to QCR Holdings, Inc.	2,327,046	2,259,488	5,016,730	3,922,793
Total assets	1,157,927,167	1,030,910,790	1,157,927,167	1,030,910,790
Provision for loan/lease losses	392,469	638,221	787,915	1,077,885
Goodwill	3,222,688	3,222,688	3,222,688	3,222,688
Cedar Rapids Bank and Trust [Member]
Total revenue	6,536,887	7,308,909	13,123,036	14,371,515
Net interest income	3,896,184	4,223,541	7,664,183	7,985,664
Net income attributable to QCR Holdings, Inc.	1,413,869	1,355,089	2,681,135	2,589,513
Total assets	581,059,340	573,534,805	581,059,340	573,534,805
Provision for loan/lease losses	225,000	410,000	575,000	785,000
Rockford Bank and Trust [Member]
Total revenue	3,648,057	3,386,900	6,768,852	6,668,880
Net interest income	2,458,333	2,207,957	4,891,039	4,286,062
Net income attributable to QCR Holdings, Inc.	402,494	66,276	795,969	289,407
Total assets	301,189,716	280,132,269	301,189,716	280,132,269
Provision for loan/lease losses	431,000	624,000	466,000	877,000
Wealth Management [Member]
Total revenue	1,531,560	1,444,978	2,936,754	2,926,997
Net income attributable to QCR Holdings, Inc.	156,523	192,264	316,406	483,652
All Other [Member]
Total revenue	4,379,005	3,938,351	8,990,997	7,456,594
Net interest income	(371,609)	(312,350)	(757,903)	(940,136)
Net income attributable to QCR Holdings, Inc.	3,110,821	2,677,173	6,407,185	4,861,431
Total assets	194,399,498	189,364,559	194,399,498	189,364,559
Intersegment Elimination [Member]
Total revenue	(4,430,041)	(3,930,816)	(9,088,522)	(7,523,117)
Net income attributable to QCR Holdings, Inc.	(4,338,597)	(3,875,321)	(8,908,451)	(7,346,867)
Total assets	(191,149,975)	(195,454,080)	(191,149,975)	(195,454,080)
Consolidated [Member]
Total revenue	23,602,037	24,035,457	46,932,719	47,743,813
Net interest income	14,515,493	13,951,055	28,718,946	26,159,857
Net income attributable to QCR Holdings, Inc.	3,072,156	2,674,969	6,308,974	4,799,929
Total assets	2,043,425,746	1,878,488,343	2,043,425,746	1,878,488,343
Provision for loan/lease losses	1,048,469	1,672,221	1,828,915	2,739,885
Goodwill	$ 3,222,688	$ 3,222,688	$ 3,222,688	$ 3,222,688