Fair Value (Changes Level 3 assets (fair value, recurring)) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Purchases, acquired, sales and settlements:
Gains included in net gains on sale of loans held for sale	$ 8,475	$ 11,056
Interest rate lock commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	3,168	2,496	$ 2,496
Total gains (losses):
Included in earnings	4,727		288
Purchases, acquired, sales and settlements:
Issuances	138		5,428
Settlements	(1,077)		(5,044)
Balance at period end	6,956		3,168
Gains included in net gains on sale of loans held for sale	7,000		3,200
Z-TRANCHE Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	2,039	4,947	4,947
Total gains (losses):
Included in earnings	0		(3,038)
Included in other comprehensive income	(265)		982
Purchases, acquired, sales and settlements:
Purchases	0		6
Sales	0		(736)
Settlements	0		(122)
Balance at period end	1,774		2,039
Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	846	$ 0	0
Total gains (losses):
Included in earnings	121		0
Included in other comprehensive income	(91)		106
Purchases, acquired, sales and settlements:
Purchases	0		0
Acquired	0		740
Sales	(546)		0
Settlements	0		0
Balance at period end	$ 330		$ 846