Commercial Mortgage Banking - Summary of Changes in Carrying Value of Mortgage Servicing Rights (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Transfers and Servicing
Balance at beginning of period		$ 28,168	$ 30,140
Originations	[1]	1,388	601
Purchases		111	208
Disposals	[1]	(861)	(2,328)
Amortization expense		(782)	(230)
Balance at end of period		$ 28,024	$ 28,391

[1] Includes refinancings