Note 5 - Business Segment Information (Detail) - Selected Financial Information on the Company’s Business Segments (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Net interest income	$ 14,191,317	$ 14,203,453
Net income attributable to QCR Holdings, Inc.	3,265,144	3,236,818
Total assets	2,143,990,652		2,093,730,492
Provision for loan/lease losses	1,057,782	780,446
Goodwill	3,222,688		3,222,688
Quad City Bank and Trust [Member]
Total revenue	12,055,661	12,265,033
Net interest income	8,391,538	8,389,042
Net income attributable to QCR Holdings, Inc.	2,497,025	2,689,685
Total assets	1,223,662,809	1,114,376,297
Provision for loan/lease losses	357,782	395,446
Goodwill	3,222,688	3,222,688
Cedar Rapids Bank and Trust [Member]
Total revenue	6,928,351	6,586,149
Net interest income	3,844,882	3,767,999
Net income attributable to QCR Holdings, Inc.	1,720,811	1,267,266
Total assets	598,842,406	566,158,474
Provision for loan/lease losses	300,000	350,000
Rockford Bank and Trust [Member]
Total revenue	3,184,059	3,120,795
Net interest income	2,305,077	2,432,706
Net income attributable to QCR Holdings, Inc.	96,242	393,475
Total assets	322,544,243	312,595,782
Provision for loan/lease losses	400,000	35,000
Wealth Management [Member]
Total revenue	1,649,011	1,405,194
Net income attributable to QCR Holdings, Inc.	213,007	159,883
All Other [Member]
Total revenue	4,732,570	4,611,992
Net interest income	(350,180)	(356,376)
Net income attributable to QCR Holdings, Inc.	3,265,144	3,296,363
Total assets	199,591,558	198,977,794
Intersegment Elimination [Member]
Total revenue	(4,808,141)	(4,658,481)
Net interest income		(29,918)
Net income attributable to QCR Holdings, Inc.	(4,527,085)	(4,569,854)
Total assets	(200,650,364)	(199,110,154)
Consolidated [Member]
Total revenue	23,741,511	23,330,682
Net interest income	14,191,317	14,203,453
Net income attributable to QCR Holdings, Inc.	3,265,144	3,236,818
Total assets	2,143,990,652	1,992,998,193
Provision for loan/lease losses	1,057,782	780,446
Goodwill	$ 3,222,688	$ 3,222,688