Note 5 - Business Segment Information (Detail) - Selected Financial Information on the Company’s Business Segments (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Net interest income	$ 14,629,518	$ 13,828,704	$ 43,348,464	$ 39,988,561
Net income attributable to QCR Holdings, Inc.	3,057,333	2,163,155	9,366,307	6,963,084
Total assets	2,023,946,072		2,023,946,072		1,966,610,054
Provision for loan/lease losses			3,325,109	5,196,850
Goodwill	3,222,688		3,222,688		3,222,688
Quad City Bank and Trust [Member]
Total revenue	11,643,674	12,147,213	36,196,909	35,990,157
Net interest income	8,602,967	7,944,108	25,524,594	22,772,375
Net income attributable to QCR Holdings, Inc.	2,586,303	1,854,914	7,603,033	5,777,707
Total assets	1,134,296,418	1,056,656,935	1,134,296,418	1,056,656,935
Provision for loan/lease losses	350,194	1,158,965	1,138,109	2,236,850
Goodwill	3,222,688	3,222,688	3,222,688	3,222,688
Cedar Rapids Bank and Trust [Member]
Total revenue	6,706,485	7,110,970	19,829,521	21,482,485
Net interest income	4,027,693	3,873,339	11,691,876	11,859,003
Net income attributable to QCR Holdings, Inc.	1,532,946	1,375,114	4,214,081	3,964,627
Total assets	587,057,961	565,822,310	587,057,961	565,822,310
Provision for loan/lease losses	300,000	250,000	875,000	1,035,000
Rockford Bank and Trust [Member]
Total revenue	2,897,098	3,377,454	9,665,950	10,046,334
Net interest income	2,368,483	2,355,471	7,259,522	6,641,533
Net income attributable to QCR Holdings, Inc.	(313,019)	(243,710)	482,950	45,697
Total assets	299,947,837	287,574,174	299,947,837	287,574,174
Provision for loan/lease losses	846,000	1,048,000	1,312,000	1,925,000
Wealth Management [Member]
Total revenue	1,490,297	1,311,647	4,427,051	4,238,644
Net income attributable to QCR Holdings, Inc.	108,950	257,611	425,356	741,263
All Other [Member]
Total revenue	4,542,612	3,319,882	13,533,609	10,776,476
Net interest income	(369,625)	(344,214)	(1,127,528)	(1,284,350)
Net income attributable to QCR Holdings, Inc.	3,077,515	2,192,761	9,484,700	7,054,192
Total assets	196,448,244	193,059,135	196,448,244	193,059,135
Intersegment Elimination [Member]
Total revenue	(3,675,459)	(3,362,429)	(13,115,614)	(10,885,546)
Net income attributable to QCR Holdings, Inc.	(3,935,362)	(3,273,535)	(12,843,813)	(10,620,402)
Total assets	(193,804,388)	(204,152,062)	(193,804,388)	(204,152,062)
Consolidated [Member]
Total revenue	23,604,707	23,904,737	70,537,426	71,648,550
Net interest income	14,629,518	13,828,704	43,348,464	39,988,561
Net income attributable to QCR Holdings, Inc.	3,057,333	2,163,155	9,366,307	6,963,084
Total assets	2,023,946,072	1,898,960,492	2,023,946,072	1,898,960,492
Provision for loan/lease losses	1,496,194	2,456,965	3,325,109	5,196,850
Goodwill	$ 3,222,688	$ 3,222,688	$ 3,222,688	$ 3,222,688