Fair Value - Changes in Level 3 Assets Measured at Fair Value on a Recurring Basis (Details) - Recurring Basis [Member] - Level 3 [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
MSR [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		$ 80,239	$ 74,007
Total net (loss) gain included in Mortgage banking, net	[1]	(11,830)	(10,513)
Additions		15,860	16,745
Sales		0	0
Ending Balance		84,269	80,239
The amount of total gains (losses) for the period included in earnings that are attributable to the change in unrealized gains or losses still held, end of period		(1,050)	(407)
Other Assets - Derivatives [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		1,001	1,113
Total net (loss) gain included in Mortgage banking, net	[1]	4,165	10,128
Additions		0	0
Sales		(4,266)	(10,240)
Ending Balance		900	1,001
The amount of total gains (losses) for the period included in earnings that are attributable to the change in unrealized gains or losses still held, end of period		$ (1,569)	$ 753

[1] Total net (loss) gain included in Mortgage banking, net relating to the MSR includes changes in fair value due to market changes and due to run-off.