Consolidated Statements of Income - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest and dividend income:
Loans/leases, including fees		$ 91,235,049	$ 74,615,499	$ 69,423,001
Securities:
Taxable		4,585,300	6,772,244	9,618,436
Nontaxable		9,686,844	7,782,370	6,074,896
Interest-bearing deposits at financial institutions		393,048	304,602	299,227
Restricted investment securities		522,047	503,764	528,660
Federal funds sold		45,447	24,774	21,036
Total interest and dividend income		106,467,735	90,003,253	85,965,256
Interest expense:
Deposits		6,018,366	4,495,538	4,508,921
Short-term borrowings		93,934	210,306	233,930
Federal Home Loan Bank advances		1,284,212	3,511,541	6,025,749
Other borrowings		3,317,513	4,233,193	4,890,909
Junior subordinated debentures		1,236,933	1,255,951	1,234,619
Total interest expense		11,950,958	13,706,529	16,894,128
Net interest income		94,516,777	76,296,724	69,071,128
Provision for loan/lease losses		(7,478,166)	(6,870,900)	(6,807,000)
Net interest income after provision for loan/lease losses		87,038,611	69,425,824	62,264,128
Noninterest income:
Trust department fees		6,164,137	6,131,209	5,715,151
Investment advisory and management fees		2,992,811	2,971,964	2,798,170
Deposit service fees		4,439,455	3,784,935	3,809,539
Gains on sales of residential real estate loans, net		431,313	322,872	460,721
Gains on sales of government guaranteed portions of loans, net		3,159,073	1,304,575	2,040,638
Swap fee income		1,708,204	1,717,552	154,800
Securities gains, net		4,592,398	798,983	92,363
Earnings on bank-owned life insurance		1,771,396	1,762,107	1,721,507
Debit card fees		1,814,488	1,244,912	1,143,738
Correspondent banking fees		1,050,142	1,190,411	1,064,030
Other		2,913,458	3,133,801	2,280,622
Total noninterest income		31,036,875	24,363,321	21,281,279
Noninterest expenses:
Salaries and employee benefits		46,317,060	42,967,915	40,337,055
Occupancy and equipment expense		8,404,605	7,042,706	7,385,526
Professional and data processing fees		7,113,443	5,523,447	6,191,574
Acquisition costs		2,441,173
FDIC insurance, other insurance and regulatory fees		2,549,314	2,724,968	2,895,494
Loan/lease expense		662,299	882,591	665,602
Net cost of operations of other real estate		591,303	(1,092,401)	603,092
Advertising and marketing		2,127,566	1,900,539	1,985,121
Bank service charges		1,692,957	1,486,265	1,291,017
Losses on debt extinguishment, net		4,577,668	7,185,601
Correspondent banking expense		750,646	703,495	635,630
Other		4,257,878	3,866,896	3,563,789
Total noninterest expenses		81,485,912	73,192,022	65,553,900
Income before income taxes		36,589,574	20,597,123	17,991,507
Federal and state income tax expense		8,902,787	3,669,242	3,038,970
Net income		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)		$ 2.20	$ 1.64	$ 1.75
Diluted earnings (loss) per common share (in dollars per share) (in dollars per share)		$ 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 and common equivalent shares outstanding (in shares)		12,766,003	10,499,841	8,048,661
Common cash dividends declared, dividends per share (in dollars per share)		$ 0.16	$ 0.08	$ 0.08

[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.