FDIC Indemnification Asset and True-up Payment Obligation (FDIC Indemnification Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fdic Shared Loss Expense [Abstract]
FDIC indemnification asset, expense	$ (1,403)	$ (8,040)	$ 36,398
Change in true-up payment obligation expense	0	(2,128)	(2,677)
Reimbursement to FDIC for recoveries	0	(3,413)	(2,144)
Final settlement with the FDIC on commercial loans	0	0	(1,589)
Shared-loss termination benefit	(15,814)	0	0
FDIC shared-loss expense, net	$ 1,403	$ (13,581)	$ (42,808)