Commercial Mortgage Banking - Summary of Changes in Carrying Value of Mortgage Servicing Rights (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014
Transfers and Servicing
Balance at beginning of period		$ 30,140	$ 28,879
Originations	[1]	5,726	4,252
Purchases		675	144
Disposals	[1]	(6,118)	(1,754)
Amortization expense		(829)	(2,025)
Balance at end of period		$ 29,594	$ 29,496

[1] Includes refinancings