Note 18 - Regulatory Matters (Details) - $ / shares				3 Months Ended		12 Months Ended
		Jun. 08, 2015	Jan. 09, 2009	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2009	Dec. 31, 2015
Safest Assets [Member]
Note 18 - Regulatory Matters (Details) [Line Items]
Risk Weighting of Assets								0.00%
Riskier Assets [Member]
Note 18 - Regulatory Matters (Details) [Line Items]
Risk Weighting of Assets								100.00%
Series A Preferred Stock [Member]
Note 18 - Regulatory Matters (Details) [Line Items]
Stock Redeemed or Called During Period, Shares (in Shares)		10,000		10,000	10,000	20,000
Preferred Stock, Liquidation Preference Per Share (in Dollars per share)		$ 1,000		$ 1,000		$ 1,000
Stock Issued During Period, Shares, New Issues (in Shares)			30,000				30,000
Citizens Northern [Member]
Note 18 - Regulatory Matters (Details) [Line Items]
Tier One Leverage Capital to Average Assets	[1]			10.11%		10.11%		10.79%
Compliance [Member] | Citizens Northern [Member]
Note 18 - Regulatory Matters (Details) [Line Items]
Tier One Leverage Capital to Average Assets								9.00%

[1] Tier 1 Leverage ratio is computed by dividing a bank's Tier 1 Capital by its total quarterly average assets, as defined by regulation.Payment of dividends by the Company's subsidiary banks is subject to certain regulatory restrictions as set forth in national and state banking lawsand regulations. Generally, capital distributions are limited to undistributed net income for the current and prior two years, subject to the capitalrequirements as summarized above.