Note 5 - Specific Reserve for Loans Modified as TDR's (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
TDRs with no specific allowance recorded - unpaid principal balance	$ 2,957	$ 2,513
TDRs with an allowance recorded - unpaid principal balance	2,934	964
Unpaid principal balance	5,891	3,477
TDRs with an allowance recorded - related allowance	$ 450	$ 411

Financing allowance for credit losses change in method of calculating impairment.

No definition available.

Name:	qnbc_FinancingAllowanceForCreditLossesChangeInMethodOfCalculatingImpairment
Namespace Prefix:	qnbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Financing receivables change in method of calculating impairment recorded investment.

+ References

No definition available.

+ Details

Name:	qnbc_FinancingReceivablesChangeInMethodOfCalculatingImpairmentRecordedInvestment
Namespace Prefix:	qnbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in loans modified under a troubled debt restructuring for which there is a related allowance for credit losses.

+ References

No definition available.

+ Details

Name:	qnbc_FinancingReceivablesModificationsWithNoSpecificAllowanceRecorded
Namespace Prefix:	qnbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of financing receivable modified as troubled debt restructuring.

+ References

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

- References

No definition available.

+ Details

Name:	us-gaap_ReceivablesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration