NOTE 3 - LOANS/LEASES RECEIVABLE - Impaired Loans Leases (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2020
Recorded investment with no specific allowance recorded	$ 5,813	$ 5,813	$ 3,924
Unpaid principal balance with no specific allowance recorded	6,171	6,171	4,804
Average recorded investment with no specific allowance recorded	5,379	4,760	2,576
Interest income recognized with no specific allowance recorded	26	50	79
Interest income recognized for cash payments received with no specific allowance recorded	26	50	79
Recorded investment with specific allowance recorded	7,492	7,492	10,704
Unpaid principal balance with specific allowance recorded	7,492	7,492	10,704
Average recorded investment with specific allowance recorded	7,475	6,140	7,578
Recorded investment	13,305	13,305	14,628
Unpaid principal balance	13,663	13,663	15,508
Related allowance	2,154	2,154	2,680
Average recorded investment	12,854	10,900	10,154
Interest income recognized	26	50	79
Interest income recognized for cash payments received	26	50	79
Commercial Portfolio Segment [Member]
Recorded investment with no specific allowance recorded	1,978	1,978	1,361
Unpaid principal balance with no specific allowance recorded	2,051	2,051	1,441
Average recorded investment with no specific allowance recorded	1,742	1,512	1,002
Interest income recognized with no specific allowance recorded	13	25	33
Interest income recognized for cash payments received with no specific allowance recorded	13	25	33
Recorded investment with specific allowance recorded	569	569	4,020
Unpaid principal balance with specific allowance recorded	569	569	4,020
Average recorded investment with specific allowance recorded	568	479	1,555
Recorded investment	2,547	2,547	5,381
Unpaid principal balance	2,620	2,620	5,461
Related allowance	341	341	650
Average recorded investment	2,310	1,991	2,557
Interest income recognized	13	25	33
Interest income recognized for cash payments received	13	25	33
Commercial Real Estate Portfolio Segment [Member] \| Owner Occupied Commercial Real Estate Loans [Member]
Recorded investment with no specific allowance recorded	320	320
Unpaid principal balance with no specific allowance recorded	577	577
Average recorded investment with no specific allowance recorded	174	128
Recorded investment	320	320
Unpaid principal balance	577	577
Average recorded investment	174	128
Commercial Real Estate Portfolio Segment [Member] \| Other Non-owner Occupied Commercial Real Estate Loans [Member]
Recorded investment with no specific allowance recorded	965	965	1,133
Unpaid principal balance with no specific allowance recorded	965	965	1,933
Average recorded investment with no specific allowance recorded	978	742	494
Interest income recognized with no specific allowance recorded	7	14	29
Interest income recognized for cash payments received with no specific allowance recorded	7	14	29
Recorded investment with specific allowance recorded	6,530	6,530	6,354
Unpaid principal balance with specific allowance recorded	6,530	6,530	6,354
Average recorded investment with specific allowance recorded	6,560	5,329	5,726
Recorded investment	7,495	7,495	7,487
Unpaid principal balance	7,495	7,495	8,287
Related allowance	1,692	1,692	1,938
Average recorded investment	7,538	6,071	6,220
Interest income recognized	7	14	29
Interest income recognized for cash payments received	7	14	29
Direct financing leases
Recorded investment with no specific allowance recorded	1,364	1,364	578
Unpaid principal balance with no specific allowance recorded	1,364	1,364	578
Average recorded investment with no specific allowance recorded	1,411	1,379	483
Interest income recognized with no specific allowance recorded	6	11	17
Interest income recognized for cash payments received with no specific allowance recorded	6	11	17
Recorded investment with specific allowance recorded	55	55
Unpaid principal balance with specific allowance recorded	55	55
Average recorded investment with specific allowance recorded	57	59
Recorded investment	1,419	1,419	578
Unpaid principal balance	1,419	1,419	578
Related allowance	20	20
Average recorded investment	1,468	1,438	483
Interest income recognized	6	11	17
Interest income recognized for cash payments received	6	11	17
Residential real estate
Recorded investment with no specific allowance recorded	624	624	719
Unpaid principal balance with no specific allowance recorded	652	652	719
Average recorded investment with no specific allowance recorded	524	474	476
Recorded investment with specific allowance recorded	260	260	258
Unpaid principal balance with specific allowance recorded	260	260	258
Average recorded investment with specific allowance recorded	220	206	227
Recorded investment	884	884	977
Unpaid principal balance	912	912	977
Related allowance	23	23	20
Average recorded investment	744	680	703
Installment and other consumer loans
Recorded investment with no specific allowance recorded	562	562	133
Unpaid principal balance with no specific allowance recorded	562	562	133
Average recorded investment with no specific allowance recorded	550	525	121
Recorded investment with specific allowance recorded	78	78	72
Unpaid principal balance with specific allowance recorded	78	78	72
Average recorded investment with specific allowance recorded	70	67	70
Recorded investment	640	640	205
Unpaid principal balance	640	640	205
Related allowance	78	78	72
Average recorded investment	$ 620	$ 592	$ 191

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableInterestIncomeCashBasisMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524

+ Details

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

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of interest income, recognized on cash basis, on financing receivables, for which there is no related allowance for credit losses and are recognized as impaired.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeCashBasisMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=qcrh_OwnerOccupiedCommercialRealEstateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=qcrh_OtherNonownerOccupiedCommercialRealEstateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_FinanceLeasesPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=qcrh_InstallmentAndOtherConsumerLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: