NOTE 4 - DERIVATIVES AND HEDGING ACTIVITIES - Summary of Interest Rate Cap Derivatives (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Derivative Assets	$ 198,393	$ 222,757
Interest rate swap
Derivative Assets	196,928	222,431
Interest rate cap
Derivative Assets	141	67
Cash Flow Hedging \| Interest rate swap
Derivative Assets	807
Cash Flow Hedging \| Interest rate cap
Derivative Assets	517	259
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging
Notional Amount	150,000
Fair Value - Asset	807
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument One Maturing 2023 [Member]
Notional Amount	25,000
Fair Value - Asset	$ 1	3
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument One Maturing 2023 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.75%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Two Maturing 2023 [Member]
Notional Amount	$ 50,000
Fair Value - Asset	$ 2	5
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Two Maturing 2023 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.57%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Three Maturing 2023 [Member]
Notional Amount	$ 25,000
Fair Value - Asset	$ 1	3
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Three Maturing 2023 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.80%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument One Maturing 2024 [Member]
Notional Amount	$ 25,000
Fair Value - Asset	$ 26	15
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument One Maturing 2024 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.75%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Two Maturing 2024 [Member]
Notional Amount	$ 50,000
Fair Value - Asset	$ 53	31
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Two Maturing 2024 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.57%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Three Maturing 2024 [Member]
Notional Amount	$ 25,000
Fair Value - Asset	$ 26	15
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Three Maturing 2024 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.80%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument One Maturing 2025 [Member]
Notional Amount	$ 25,000
Fair Value - Asset	$ 101	46
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument One Maturing 2025 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.75%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Two Maturing 2025 [Member]
Notional Amount	$ 50,000
Fair Value - Asset	$ 205	94
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Two Maturing 2025 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.57%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Four Maturing 2025 [Member]
Notional Amount	$ 25,000
Fair Value - Asset	$ 102	47
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Derivative Instrument Four Maturing 2025 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.80%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| QCBT - Loans
Notional Amount	$ 35,000
Fair Value - Asset	$ 192
Receive Rate	1.40%
Pay Rate	2.81%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| CRBT - Loans
Notional Amount	$ 50,000
Fair Value - Asset	$ 274
Receive Rate	1.40%
Pay Rate	2.81%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| CSB - Loans
Notional Amount	$ 40,000
Fair Value - Asset	$ 204
Receive Rate	1.40%
Pay Rate	2.81%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| SFCB - Loans
Notional Amount	$ 25,000
Fair Value - Asset	$ 137
Receive Rate	1.40%
Pay Rate	2.81%
Designated as Hedging Instrument \| Derivative Assets \| Cash Flow Hedging \| Interest rate cap
Notional Amount	$ 300,000
Fair Value - Asset	517	259
Designated as Hedging Instrument \| Derivative Liabilities \| Cash Flow Hedging \| Interest rate swap
Notional Amount	39,000
Fair Value - Liability	(4,522)	(6,839)
Designated as Hedging Instrument \| Derivative Liabilities \| Cash Flow Hedging \| QCR Holdings Statutory Trust II
Notional Amount	10,000
Fair Value - Liability	$ (1,169)	(1,767)
Receive Rate	2.98%
Pay Rate	5.85%
Designated as Hedging Instrument \| Derivative Liabilities \| Cash Flow Hedging \| QCR Holdings Statutory Trust III
Notional Amount	$ 8,000
Fair Value - Liability	$ (936)	(1,414)
Receive Rate	2.98%
Pay Rate	5.85%
Designated as Hedging Instrument \| Derivative Liabilities \| Cash Flow Hedging \| QCR Holdings Statutory Trust V
Notional Amount	$ 10,000
Fair Value - Liability	$ (1,135)	(1,721)
Receive Rate	1.68%
Pay Rate	4.54%
Designated as Hedging Instrument \| Derivative Liabilities \| Cash Flow Hedging \| Community National Statutory Trust II
Notional Amount	$ 3,000
Fair Value - Liability	$ (350)	(529)
Receive Rate	2.29%
Pay Rate	5.17%
Designated as Hedging Instrument \| Derivative Liabilities \| Cash Flow Hedging \| Community National Statutory Trust III
Notional Amount	$ 3,500
Fair Value - Liability	$ (408)	(616)
Receive Rate	1.87%
Pay Rate	4.75%
Designated as Hedging Instrument \| Derivative Liabilities \| Cash Flow Hedging \| Guaranty Bankshares Statutory Trust I
Notional Amount	$ 4,500
Fair Value - Liability	$ (524)	(792)
Receive Rate	1.87%
Pay Rate	4.75%
Non Designated \| Interest rate swap
Derivative Assets	$ 196,928	222,431
Non Designated \| Derivative Assets
Notional Amount	75,000
Derivative Assets	141	67
Non Designated \| Derivative Assets \| Derivative Instrument One Maturing 2023 [Member]
Notional Amount	25,000
Derivative Assets	$ 1	2
Non Designated \| Derivative Assets \| Derivative Instrument One Maturing 2023 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.90%
Non Designated \| Derivative Assets \| Derivative Instrument One Maturing 2024 [Member]
Notional Amount	$ 25,000
Derivative Assets	$ 26	15
Non Designated \| Derivative Assets \| Derivative Instrument One Maturing 2024 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.90%
Non Designated \| Derivative Assets \| Derivative Instrument One Maturing 2025 [Member]
Notional Amount	$ 25,000
Derivative Assets	$ 114	$ 50
Non Designated \| Derivative Assets \| Derivative Instrument One Maturing 2025 [Member] \| London Interbank Offered Rate (LIBOR)
Derivative, Basis Spread on Variable Rate	1.90%

Represents the pay rate of the derivative instrument.

No definition available.

Name:	qcrh_DerivativesPayRate
Namespace Prefix:	qcrh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the receive rate of the derivative instrument.

+ References

No definition available.

+ Details

Name:	qcrh_DerivativesReceiveRate
Namespace Prefix:	qcrh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

+ Details

Name:	us-gaap_DerivativeAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all interest rate derivative assets designated as cash flow hedging instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959

+ Details

Name:	us-gaap_InterestRateCashFlowHedgeAssetAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all interest rate derivative liabilities designated as cash flow hedging instruments.

+ References

+ Details

Name:	us-gaap_InterestRateCashFlowHedgeLiabilityAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant