Investment Securities - Realized Gains and Losses and Proceeds from Sales (Details) - U.S. government-sponsored mortgage-backed securities - Held to maturity and trading securities - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Realized gains and losses and the proceeds from sales of securities available for sale, held to maturity and trading
Proceeds from sales	$ 3,122	$ 2,503	$ 3,122	$ 5,083
Gross gains	$ 190	$ 240	$ 190	$ 476