Fair Value Measurements - Quantitative information about Level III fair value measurements (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Impaired Loans [Member] | Discounted appraised value [Member] | Minimum [Member] | Level III [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	0.00%	0.00%
Impaired Loans [Member] | Discounted appraised value [Member] | Maximum [Member] | Level III [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	100.00%	100.00%
Impaired Loans [Member] | Discounted appraised value [Member] | Weighted Average [Member] | Level III [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	5.00%	7.00%
Repossessed Assets [Member] | Market Approach Valuation Technique [Member] | Weighted Average [Member] | Level III [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	50.00%	50.00%
Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Fair Value	$ 8,419	$ 5,799
Repossessed assets	1,044	1,132
Nonrecurring [Member] | Level III [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Fair Value	4,068	4,510
Repossessed assets	$ 1,044	$ 1,132