Investment Securities (Details 4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value
Less than 12 months	$ 52,914		$ 52,914		$ 154,826
12 months or more	9,130		9,130		1,571
Total	62,044		62,044		156,397
Unrealized Losses
Less than 12 months	(58)		(58)		(2,760)
12 months or more	(6)		(6)		(2)
Total	(64)		(64)		$ (2,762)
Sales of Available-For-Sale Securities
Gains from sales of available-for-sale securities		$ 3,300	2,800	$ 5,600
Proceeds from sales of available-for-sale securities	$ 8,900	$ 19,600	$ 31,000	$ 31,800