Investment Securities - Narrative (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) purchase_agreement	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($)
Investment Securities
Number of inverse putable reverse repurchase of the Bank's secured by collateral | purchase_agreement	3
Value of inverse putable reverse repurchases secured by collateral	$ 28,500,000
OTTI losses	207,000	$ 0	$ 0
Gross gains	762,000	1,000	117,000
Gross losses	9,000	5,000	1,000
Proceeds from sale or maturity of securities available for sale	185,000,000	677,000	7,200,000
Proceeds from sale or maturity of securities	3,294,000		0
Accumulated other comprehensive income (loss) before tax amount	2,500,000	562,000
Accumulated other comprehensive income, net of tax	1,461,000	$ 332,000	1,285,000
FHLB stock	14,400,000
FRB stock	7,900,000
Other stock	3,600,000
Excess repurchased	0		$ 5,900,000
HOA
Investment Securities
Value of inverse putable reverse repurchases secured by collateral	16,500,000
Mortgage-backed securities
Investment Securities
Estimated par value of securities pledged as collateral for the Bank's inverse putable reverse repurchases	61,600,000
Fair value of securities pledged as collateral for the Bank's inverse putable reverse repurchases	$ 63,800,000