Note 17 - Earnings Per Share - Basic and Diluted (Details) - USD ($)		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income		$ 8,529,330	$ 6,107,501	$ 6,676,467	$ 6,373,489	$ 6,784,823	$ 6,488,987	$ (523,818)	$ 4,177,889	$ 27,686,787	$ 16,927,881	$ 14,952,537
Less: preferred stock dividends												1,081,877
Net income attributable to QCR Holdings, Inc. common stockholders										$ 27,686,787	$ 16,927,881	$ 13,870,660
Basic earnings (loss) per common share (in dollars per share) (in dollars per share)		$ 0.65	$ 0.47	$ 0.54	$ 0.54	$ 0.58	$ 0.55	$ (0.05)	$ 0.52	$ 2.20	$ 1.64	$ 1.75
Diluted earnings (loss) per common share (in dollars per share) (in dollars per share)		$ 0.64	$ 0.46	$ 0.53	$ 0.53	$ 0.57	$ 0.55	$ (0.05)	$ 0.52	$ 2.17	$ 1.61	$ 1.72
Weighted average common shares outstanding (in shares)	[1]									12,570,767	10,345,286	7,925,220
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan** (in shares)	[2]									195,236	154,555	123,441
Weighted average common and common equivalent shares outstanding (in shares)										12,766,003	10,499,841	8,048,661

[1] The increase in weighted average common shares outstanding from 2014 to 2015 was primarily due to the common stock issuance discussed in Note 16 to the Consolidated Financial Statements. The increase in weighted average common shares outstanding from 2015 to 2016 was primarily due to the common stock issuance discussed in Note 2 to the Consolidated Financial Statements.

[2] Excludes anti-dilutive shares of 17,739, 36,572, and 124,983 at December 31, 2016, 2015 and 2014, respectively.