Investment Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Integer	Dec. 31, 2015 USD ($) Integer
Investments, Debt and Equity Securities [Abstract]
Increase in amortized cost basis of available-for-sale securities $210,000 Net increase to accumulated	$ 210,000
Net increase to accumulated other comprehensive income net of tax	$ 7,400
Number of Investment Securities Sold | Integer	84	74
Available-for-sale Securities Pledged as Collateral	$ 121,900	$ 142,500
Description of Holding Securities	there were no holdings of securities of any one issuer, other than the U.S. Government and its agencies, in an amount greater than 10% of stockholders' equity.	there were no holdings of securities of any one issuer, other than the U.S. Government and its agencies, in an amount greater than 10% of stockholders' equity.