Note 18 - Regulatory Matters - Regulatory Ratios of the Consolidated Company and Its Subsidiary Banks (Details) - USD ($)		Dec. 31, 2016		Dec. 31, 2015
Consolidated Entities [Member]
Common Equity Tier 1 Risk-based Capital, actual, amount	[1]	$ 187,474,000		$ 172,871,000
Common Equity Tier 1 Risk-based Capital, actual, ratio	[1]	16.43%		14.91%
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 51,349,000		$ 52,184,000
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	4.50%		4.50%
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, amount
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, ratio
Tier 1 Risk-based Capital, actual, amount	[1]	$ 219,974,000		$ 220,371
Tier 1 Risk-based Capital, actual, ratio	[1]	19.28%		19.00%
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 68,466,000		$ 69,579
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	6.00%		6.00%
Tier 1 Risk-based Capital, to Be Well-capitalized, amount
Tier 1 Risk-based Capital, to Be Well-capitalized, ratio
Total Risk-based Capital, actual, amount		$ 229,318,000	[1]	$ 230,686	[2]
Total Risk-based Capital, actual, ratio		20.10%	[1]	19.89%	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, amount		$ 91,288,000	[1]	$ 92,772	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, ratio		8.00%	[1]	8.00%	[2]
Total Risk-based Capital, to Be Well-capitalized, amount
Total Risk-based Capital, to Be Well-capitalized, ratio
Tier 1 Leverage Capital, actual, amount		$ 219,974,000	[2]	$ 220,371
Tier 1 Leverage Capital, actual, ratio		13.20%	[2]	12.46%
Tier 1 Leverage Capital, for Capital Adequacy Purposes, amount		$ 66,656,000	[2]	$ 70,746
Tier 1 Leverage Capital, for Capital Adequacy Purposes, ratio		4.00%	[2]	4.00%
Ter 1 Leverage Capital, to Be Well-capitalized, amount			[2]
Tier 1 Leverage Capital, to Be Well-capitalized, ratio			[2]
Farmers Bank [Member]
Common Equity Tier 1 Risk-based Capital, actual, amount	[1]	$ 64,016,000		$ 63,552
Common Equity Tier 1 Risk-based Capital, actual, ratio	[1]	16.53%		15.57%
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 17,425,000		$ 18,366
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	4.50%		4.50%
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 25,170,000		$ 26,529
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	6.50%		6.50%
Tier 1 Risk-based Capital, actual, amount	[1]	$ 64,016,000		$ 63,552
Tier 1 Risk-based Capital, actual, ratio	[1]	16.53%		15.57%
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 23,234,000		$ 24,488
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	6.00%		6.00%
Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 30,978,000		$ 32,651
Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	8.00%		8.00%
Total Risk-based Capital, actual, amount		$ 66,720,000	[1]	$ 66,728	[2]
Total Risk-based Capital, actual, ratio		17.23%	[1]	16.35%	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, amount		$ 30,978,000	[1]	$ 32,651	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, ratio		8.00%	[1]	8.00%	[2]
Total Risk-based Capital, to Be Well-capitalized, amount		$ 38,723,000	[1]	$ 40,814	[2]
Total Risk-based Capital, to Be Well-capitalized, ratio		10.00%	[1]	10.00%	[2]
Tier 1 Leverage Capital, actual, amount		$ 64,016,000	[2]	$ 63,552
Tier 1 Leverage Capital, actual, ratio		9.80%	[2]	9.20%
Tier 1 Leverage Capital, for Capital Adequacy Purposes, amount		$ 26,121,000	[2]	$ 27,629
Tier 1 Leverage Capital, for Capital Adequacy Purposes, ratio		4.00%	[2]	4.00%
Ter 1 Leverage Capital, to Be Well-capitalized, amount		$ 32,651,000	[2]	$ 34,537
Tier 1 Leverage Capital, to Be Well-capitalized, ratio		5.00%	[2]	5.00%
United Bank [Member]
Common Equity Tier 1 Risk-based Capital, actual, amount	[1]	$ 58,180,000		$ 65,862
Common Equity Tier 1 Risk-based Capital, actual, ratio	[1]	15.54%		18.67%
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 16,848,000		$ 15,879
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	4.50%		4.50%
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 24,337,000		$ 22,936
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	6.50%		6.50%
Tier 1 Risk-based Capital, actual, amount	[1]	$ 58,180,000		$ 65,862
Tier 1 Risk-based Capital, actual, ratio	[1]	15.54%		18.67%
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 22,465,000		$ 21,171
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	6.00%		6.00%
Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 29,953,000		$ 28,228
Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	8.00%		8.00%
Total Risk-based Capital, actual, amount		$ 61,680,000	[1]	$ 69,456	[2]
Total Risk-based Capital, actual, ratio		16.47%	[1]	19.68%	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, amount		$ 29,953,000	[1]	$ 28,228	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, ratio		8.00%	[1]	8.00%	[2]
Total Risk-based Capital, to Be Well-capitalized, amount		$ 37,441,000	[1]	$ 35,286	[2]
Total Risk-based Capital, to Be Well-capitalized, ratio		10.00%	[1]	10.00%	[2]
Tier 1 Leverage Capital, actual, amount		$ 58,180,000	[2]	$ 65,862
Tier 1 Leverage Capital, actual, ratio		12.38%	[2]	12.89%
Tier 1 Leverage Capital, for Capital Adequacy Purposes, amount		$ 18,798,000	[2]	$ 20,442
Tier 1 Leverage Capital, for Capital Adequacy Purposes, ratio		4.00%	[2]	4.00%
Ter 1 Leverage Capital, to Be Well-capitalized, amount		$ 23,497,000	[2]	$ 25,553
Tier 1 Leverage Capital, to Be Well-capitalized, ratio		5.00%	[2]	5.00%
First Citizens Bank [Member]
Common Equity Tier 1 Risk-based Capital, actual, amount	[1]	$ 28,324,000		$ 28,743
Common Equity Tier 1 Risk-based Capital, actual, ratio	[1]	13.56%		13.55%
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 9,401,000		$ 9,543
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	4.50%		4.50%
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 13,580,000		$ 13,784
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	6.50%		6.50%
Tier 1 Risk-based Capital, actual, amount	[1]	$ 28,324,000
Tier 1 Risk-based Capital, actual, ratio	[1]	13.56%		13.55%
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 12,535,000		$ 12,724
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	6.00%		6.00%
Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 16,714,000		$ 16,965
Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	8.00%		8.00%
Total Risk-based Capital, actual, amount		$ 29,590,000	[1]	$ 30,048	[2]
Total Risk-based Capital, actual, ratio		14.16%	[1]	14.17%	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, amount		$ 16,714,000	[1]	$ 16,965	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, ratio		8.00%	[1]	8.00%	[2]
Total Risk-based Capital, to Be Well-capitalized, amount		$ 20,892,000	[1]	$ 21,207	[2]
Total Risk-based Capital, to Be Well-capitalized, ratio		10.00%	[1]	10.00%	[2]
Tier 1 Leverage Capital, actual, amount		$ 28,324,000	[2]	$ 28,743
Tier 1 Leverage Capital, actual, ratio		9.76%	[2]	9.20%
Tier 1 Leverage Capital, for Capital Adequacy Purposes, amount		$ 11,606,000	[2]	$ 12,493
Tier 1 Leverage Capital, for Capital Adequacy Purposes, ratio		4.00%	[2]	4.00%
Ter 1 Leverage Capital, to Be Well-capitalized, amount		$ 14,507,000	[2]	$ 15,617
Tier 1 Leverage Capital, to Be Well-capitalized, ratio		5.00%	[2]	5.00%
Citizens Northern [Member]
Common Equity Tier 1 Risk-based Capital, actual, amount	[1]	$ 24,661,000		$ 25,770
Common Equity Tier 1 Risk-based Capital, actual, ratio	[1]	15.24%		14.42%
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 7,280,000		$ 8,044
Common Equity Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	4.50%		4.50%
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 10,516,000		$ 11,619
Common Equity Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	6.50%		6.50%
Tier 1 Risk-based Capital, actual, amount	[1]	$ 24,661,000		$ 25,770
Tier 1 Risk-based Capital, actual, ratio	[1]	15.24%		14.42%
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, amount	[1]	$ 9,707,000		$ 10,725
Tier 1 Risk-based Capital, for Capital Adequacy Purposes, ratio	[1]	6.00%		6.00%
Tier 1 Risk-based Capital, to Be Well-capitalized, amount	[1]	$ 12,942,000		$ 14,300
Tier 1 Risk-based Capital, to Be Well-capitalized, ratio	[1]	8.00%		8.00%
Total Risk-based Capital, actual, amount		$ 26,534,000	[1]	$ 28,004	[2]
Total Risk-based Capital, actual, ratio		16.40%	[1]	15.67%	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, amount		$ 12,942,000	[1]	$ 14,300	[2]
Total Risk-based Capital, for Capital Adequacy Purposes, ratio		8.00%	[1]	8.00%	[2]
Total Risk-based Capital, to Be Well-capitalized, amount		$ 16,178,000	[1]	$ 17,875	[2]
Total Risk-based Capital, to Be Well-capitalized, ratio		10.00%	[1]	10.00%	[2]
Tier 1 Leverage Capital, actual, amount		$ 24,661,000	[2]	$ 25,770
Tier 1 Leverage Capital, actual, ratio		10.68%	[2]	10.79%
Tier 1 Leverage Capital, for Capital Adequacy Purposes, amount		$ 9,234,000	[2]	$ 9,555
Tier 1 Leverage Capital, for Capital Adequacy Purposes, ratio		4.00%	[2]	4.00%
Ter 1 Leverage Capital, to Be Well-capitalized, amount		$ 11,543,000	[2]	$ 11,943
Tier 1 Leverage Capital, to Be Well-capitalized, ratio		5.00%	[2]	5.00%

[1] Common Equity Tier 1 Risk-based, Tier 1 Risk-based, and Total Risk-based Capital ratios are computed by dividing a bank's Common Equity Tier 1, 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.

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