Note 9 - Short-Term Borrowings ((Details Textual)	Dec. 31, 2017 USD ($) FederalFund	Dec. 31, 2016 USD ($)
Short-term Borrowings [Line Items]
Available-for-sale Securities Pledged as Collateral	$ 202,887,000	$ 166,628,000
Federal Funds Unsecured Number of Lines \| FederalFund	4
Federal Funds Unsecured Lines	$ 46,000,000
Federal Funds Purchased	0	0
Securities Sold under Agreements to Repurchase [Member]
Short-term Borrowings [Line Items]
Available for Sale Securities Pledged as Collateral Amortized Cost	53,112,000	52,920,000
Available-for-sale Securities Pledged as Collateral	$ 51,823,000	$ 52,314,000

The amortized cost of available-for-sale securities that serve as collateral for borrowings.

No definition available.

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

- Definition

Amount of Federal Funds lines granted by correspondent banks.

+ References

No definition available.

+ Details

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

- Definition

The number of Federal Fund lines granted by correspondent banks.

+ References

No definition available.

+ Details

Name:	qnbc_FederalFundsUnsecuredNumberOfLines
Namespace Prefix:	qnbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The fair value of available-for-sale securities that serve as collateral for borrowings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5086-111524

+ Details

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

- Definition

Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(1))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: