Securities (Summary of Proceeds and Realized Gain/(Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Securities [Abstract]
Reversal of existing deferred fees and premiums	$ 5,056	$ 4,285	$ 11,634
Gross realized gains from sold and called securities	3		509
Gross realized losses from sold and called securities	(2)	(15)	(4)
Gross gains from business combinations	3		3
Net (losses) gains	$ 4	$ (15)	$ 508