NOTE 3 - LOANS/LEASES RECEIVABLE - Loans Leases Nonperforming Loans Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accruing Past Due 90 Days or More	$ 99	$ 33
Nonaccrual Loans/Leases	12,099	7,902
Accruing TDRs	1,300	1,700
Loans and Leases Receivable, Net of Deferred Income	$ 4,138,596	$ 3,681,346
Percentage of Total NPLs	100.00%	100.00%
Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More	$ 99	$ 33
Nonaccrual Loans/Leases	12,099	7,902
Accruing TDRs	920	979
Loans and Leases Receivable, Net of Deferred Income	$ 13,118	$ 8,914
Percentage of Total NPLs	100.00%	100.00%
Commercial Portfolio Segment [Member]
Accruing Past Due 90 Days or More	$ 62
Nonaccrual Loans/Leases	1,670	$ 1,236
Loans and Leases Receivable, Net of Deferred Income	1,850,110	1,507,825
Commercial Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More	62
Nonaccrual Loans/Leases	1,670	1,236
Accruing TDRs	652	646
Loans and Leases Receivable, Net of Deferred Income	$ 2,384	$ 1,882
Percentage of Total NPLs	18.17%	21.12%
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income	$ 1,869,162	$ 1,736,396
Commercial Real Estate Portfolio Segment [Member] \| Owner Occupied Commercial Real Estate Loans [Member]
Nonaccrual Loans/Leases	320	34
Loans and Leases Receivable, Net of Deferred Income	467,537	443,989
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Loans and Leases Receivable, Net of Deferred Income	441,364	378,797
Commercial Real Estate Portfolio Segment [Member] \| Other Non-owner Occupied Commercial Real Estate Loans [Member]
Nonaccrual Loans/Leases	7,492	3,853
Loans and Leases Receivable, Net of Deferred Income	960,261	913,610
Commercial Real Estate Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member] \| Owner Occupied Commercial Real Estate Loans [Member]
Nonaccrual Loans/Leases	320	34
Loans and Leases Receivable, Net of Deferred Income	$ 320	$ 34
Percentage of Total NPLs	2.44%	0.38%
Commercial Real Estate Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member] \| Other Non-owner Occupied Commercial Real Estate Loans [Member]
Nonaccrual Loans/Leases	$ 7,492	$ 3,853
Loans and Leases Receivable, Net of Deferred Income	$ 7,492	$ 3,853
Percentage of Total NPLs	57.12%	43.22%
Finance Leases Portfolio Segment [Member]
Nonaccrual Loans/Leases	$ 1,040	$ 1,517
Loans and Leases Receivable, Net of Deferred Income	79,105	87,869
Finance Leases Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member]
Nonaccrual Loans/Leases	1,040	1,517
Accruing TDRs	268	333
Loans and Leases Receivable, Net of Deferred Income	$ 1,308	$ 1,850
Percentage of Total NPLs	9.97%	20.75%
Residential Portfolio Segment [Member]
Nonaccrual Loans/Leases	$ 936	$ 706
Loans and Leases Receivable, Net of Deferred Income	241,069	239,904
Residential Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member]
Nonaccrual Loans/Leases	936	706
Loans and Leases Receivable, Net of Deferred Income	$ 936	$ 706
Percentage of Total NPLs	7.14%	7.92%
Consumer Portfolio Segment [Member]
Accruing Past Due 90 Days or More	$ 37	$ 33
Nonaccrual Loans/Leases	640	556
Loans and Leases Receivable, Net of Deferred Income	99,150	109,352
Consumer Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member]
Accruing Past Due 90 Days or More	37	33
Nonaccrual Loans/Leases	640	556
Loans and Leases Receivable, Net of Deferred Income	$ 677	$ 589
Percentage of Total NPLs	5.16%	6.61%

Amount of financing receivable modified as troubled debt restructuring.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18845-111554

+ Details

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

- Definition

Amount of financing receivable 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable on nonaccrual status.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

+ Details

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

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

+ Details

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

- Definition

Reflects the percentage derived from dividing impaired loans on which interest has ceased to be accrued by total loans.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_NonperformingFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- 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=us-gaap_ConstructionLoansMember
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=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: