Note 10 - Regulatory Matters (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	1 Months Ended
	Jun. 30, 2015	Jan. 31, 2009	Mar. 31, 2015		Dec. 31, 2014
Series A Preferred Stock [Member] | Scenario, Forecast [Member]
Note 10 - Regulatory Matters (Details) [Line Items]
Stock Redeemed or Called During Period, Shares (in Shares)	10,000
Preferred Stock, Liquidation Preference Per Share (in Dollars per share)	$ 1,000
Preferred Stock, Redemption Amount (in Dollars)	$ 10.0
Preferred Stock, Dividend Rate, Percentage	9.00%
Series A Preferred Stock [Member]
Note 10 - Regulatory Matters (Details) [Line Items]
Stock Issued During Period, Shares, New Issues (in Shares)		30,000
Compliance [Member] | Citizens Northern [Member]
Note 10 - Regulatory Matters (Details) [Line Items]
Tier One Leverage Capital to Average Assets			9.00%
Safest Assets [Member]
Note 10 - Regulatory Matters (Details) [Line Items]
Risk Weighting of Assets			0.00%
Riskier Assets [Member]
Note 10 - Regulatory Matters (Details) [Line Items]
Risk Weighting of Assets			100.00%
Citizens Northern [Member]
Note 10 - Regulatory Matters (Details) [Line Items]
Tier One Leverage Capital to Average Assets			9.72%	[1]	10.11%	[1]

[1] Tier 1 Leverage ratio is computed by dividing a bank's Tier 1 Capital, as defined by regulation, by its total quarterly average assets.