Mortgage Servicing Rights - Schedule of Servicing Income and Expense Included in Mortgage Banking Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Transfers And Servicing [Abstract]
Gross servicing income	$ 3,660	$ 1,050	$ 8,311	$ 2,102
Servicing expenses:
Servicing asset amortization	2,796	764	6,221	1,543
Servicing asset impairment	2,402		8,089
Other servicing expenses	625	174	1,571	374
Gross servicing expenses	5,823	938	15,881	1,917
Net servicing (loss) income	$ (2,163)	$ 112	$ (7,570)	$ 185