Note 1 - Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2019 USD ($) Lease $ / shares shares	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares
Summary of Significant Accounting Policies [Line Items]
Restricted investment in stocks	$ 1,073,000	$ 797,000
Other than temporary impairment charge of restricted investment	$ 0
Lease option to extend description	QNB typically enters into lease agreements with an initial term of 5 to 10 years and subsequent additional optional terms in increments of 5 years.
Lease option to terminate description	The lease agreements also contain termination options. None of the leases contain purchase options and none transfer the ownership of the leased asset.
Number of operating lease renewed | Lease	1
Number of new operating lease renewed | Lease	2
Lease agreement subsequent additional optional term in increments	5 years
Lease agreement option to extend on increments	true
Lease option to terminate	true
Other Postretirement Benefit Expense	$ 59,000	53,000	$ 23,000
Allocated Share-based Compensation Expense	118,000	117,000	102,000
Employee service Share-based compensation, tax benefit from nonqualified compensation expense and disqualifying dispositions	$ 7,000	$ 10,000	$ 19,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share) | $ / shares	$ 3.96	$ 5.29	$ 3.88
Unrecognized Tax Benefits	$ 0
Interest accrued	0
Penalties expense	$ 2,000
Tax years subject to examination by tax authorities		2016
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Lease agreements initial terms	5 years
Lease agreement subsequent additional optional term in increments	5 years
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Lease agreements initial terms	10 years
Lease agreement subsequent additional optional term in increments	10 years
Other Assets [Member]
Summary of Significant Accounting Policies [Line Items]
Other Real Estate, Foreclosed Assets, and Repossessed Assets	$ 0	$ 0
Investment in Federal Home Loan Bank Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Restricted investment in stocks	1,061,000
Investment in Atlantic Community Bankers Bank Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Restricted investment in stocks	12,000
VISA Class B Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Restricted investment in stocks	$ 0
Number of shares owned | shares	6,502
VISA Class A Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Conversion factor per share	1.6298