Note 11 - Business Segment Information (Details) - Selected Financial Information on the Company’s Business Segments - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total revenue	$ 30,790,038	$ 26,958,315	$ 86,719,828	$ 79,279,127
Net interest income	20,137,526	17,475,331	56,410,579	51,289,915
Net income attributable to QCR Holdings, Inc.	6,488,987	4,062,665	10,143,058	11,959,716
Total assets	2,575,854,717	2,450,595,553	2,575,854,717	2,450,595,553	$ 2,524,958,100
Provision for loan/lease losses	1,635,263	1,063,323	5,694,384	3,159,364
Goodwill	3,222,688	3,222,688	3,222,688	3,222,688	3,222,688
Core deposit intangible	1,521,287	1,720,799	1,521,287	1,720,799	$ 1,670,921
Operating Segments [Member] | Wealth Management Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	2,314,406	2,082,609	6,927,453	6,387,215
Net income attributable to QCR Holdings, Inc.	373,801	358,997	1,271,661	1,205,204
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	7,936,414	5,526,296	14,489,717	16,016,503
Net interest income	(317,858)	(523,134)	(1,260,962)	(1,403,894)
Net income attributable to QCR Holdings, Inc.	6,488,988	4,062,665	10,143,059	11,959,716
Total assets	277,001,408	212,236,225	277,001,408	212,236,225
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	(7,986,520)	(5,567,505)	(14,721,751)	(16,245,340)
Net income attributable to QCR Holdings, Inc.	(7,901,197)	(5,492,285)	(14,391,210)	(15,936,257)
Total assets	(256,611,839)	(204,813,887)	(256,611,839)	(204,813,887)
Quad City Bank and Trust Company [Member] | Operating Segments [Member] | Commercial Banking Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	14,039,050	12,467,712	39,824,626	36,368,665
Net interest income	10,728,143	9,234,089	29,745,080	27,235,902
Net income attributable to QCR Holdings, Inc.	3,786,289	2,602,238	6,578,479	7,397,943
Total assets	1,328,053,105	1,274,033,270	1,328,053,105	1,274,033,270
Provision for loan/lease losses	910,263	609,657	3,466,384	1,779,698
Goodwill	3,222,688	3,222,688	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	10,390,806	8,853,958	28,662,969	25,972,122
Net interest income	6,956,027	6,179,763	19,836,835	17,820,878
Net income attributable to QCR Holdings, Inc.	2,893,397	1,861,236	4,645,136	5,577,993
Total assets	867,064,041	822,348,680	867,064,041	822,348,680
Provision for loan/lease losses	550,000	331,666	1,650,000	881,666
Core deposit intangible	1,521,287	1,720,799	1,521,287	1,720,799
Rockford Bank and Trust [Member] | Operating Segments [Member] | Commercial Banking Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	4,095,882	3,595,245	11,536,814	10,779,962
Net interest income	2,771,214	2,584,613	8,089,626	7,637,029
Net income attributable to QCR Holdings, Inc.	847,709	669,814	1,895,933	1,755,117
Total assets	360,348,002	346,791,265	360,348,002	346,791,265
Provision for loan/lease losses	$ 175,000	$ 122,000	$ 578,000	$ 498,000