Fair Value (Changes Level 3 assets (fair value, recurring)) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Purchases, acquired, sales and settlements:
Gains included in net gains on sale of loans held for sale	$ 3,828	$ 8,475
Interest rate lock commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	2,790	3,168	$ 3,168
Total gains (losses):
Included in earnings	1,062		(1,564)
Purchases, acquired, sales and settlements:
Issuances	382		5,373
Settlements	(489)		(4,187)
Balance at period end	3,745		2,790
Gains included in net gains on sale of loans held for sale	3,700		2,800
Z-TRANCHE Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	2,224	$ 2,039	2,039
Total gains (losses):
Included in earnings	2,810		0
Included in other comprehensive income	(2,166)		185
Purchases, acquired, sales and settlements:
Purchases	0		0
Sales	(2,868)		0
Settlements	0		0
Balance at period end	$ 0		$ 2,224