Covered Assets and FDIC Loss-sharing Asset (FDIC Loss-sharing Asset) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Balance at beginning of period	$ 0		$ 4,266	$ 3,535	$ 6,568
Cash paid to (received from) the FDIC, net	0		20	184	(23)
FDIC reimbursable losses, net	0		(590)	(149)	(756)
FDIC indemnification asset settlement	0	$ (3,123)	0		0
Payment from (to) FDIC to terminate loss-sharing agreements				(4,666)	0
Amortization, net	0		(315)	(414)	(2,530)
Loan impairment	0		266	40	393
Sale of other real estate	0		(49)	18	71
Valuation adjustments of other real estate owned	0		0	0	(22)
Other	0		6	91	109
Balance at end of period	$ 0	$ 0	$ 3,592	$ 0	$ 3,592
Non-Single Family Covered Assets						$ 74,000
Single Family Covered Assets						$ 26,400