FDIC Shared-Loss Receivable (Changes in Receivable from FDIC) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Receivable From FDIC For Shared-Loss Agreements [Roll Forward]
Accretion of discounts and premiums, net	$ (421)	$ (600)
Receipt of payments from FDIC	0	2,760
Post-acquisition and other adjustments, net	1,834	(2,591)
Termination of FDIC shared-loss agreements	0	240
FDIC shared-loss receivable	$ 3,636	$ 3,981	$ 2,223	$ 4,172