Note 11 - Regulatory Matters (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended							42 Months Ended				1 Months Ended
	Dec. 31, 2009	Sep. 30, 2009	Mar. 31, 2013 Safest Assets [Member]	Mar. 31, 2013 Riskier Assets [Member]	Mar. 31, 2012 Compliance [Member] United Bank [Member]	Dec. 31, 2010 Compliance [Member] Citizens Northern [Member]	Sep. 30, 2010 Compliance [Member] Citizens Northern [Member]	Mar. 31, 2013 United Bank [Member]		Dec. 31, 2012 United Bank [Member]		Dec. 31, 2010 Citizens Northern [Member]	Mar. 31, 2013 Citizens Northern [Member]		Dec. 31, 2012 Citizens Northern [Member]
Risk Weighting of Assets			0.00%	100.00%
Common Stock, Dividends, Per Share, Declared (in Dollars per share)	$ 0.10	$ 0.25
Tier One Leverage Capital to Average Assets					9.00%	8.00%	7.50%	9.79%	[1]	9.45%	[1]	8.04%	9.67%	[1]	9.36%	[1]
Capital to Risk Weighted Assets					13.00%			16.51%	[2]	16.69%	[2]		14.14%	[2]	14.22%	[2]
Payments for (Proceeds from) Other Investing Activities (in Dollars)								$ 18,900				$ 250

[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.

[2] Tier 1 Risk-based and Total Risk-based Capital ratios are computed by dividing a bank's Tier 1 or Total Capital, as defined by regulation, by a risk-weighted sum of the bank's assets, with the risk weighting determined by general standards established by regulation. The safest assets (e.g., government obligations) are assigned a weighting of 0% with riskier assets receiving higher ratings (e.g., ordinary commercial loans are assigned a weighting of 100%).