Fair Value of Assets and Liabilities - Reconciliation of Assets with Unobservable Inputs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 7,165	$ 5,182	$ 5,294	$ 3,168
Change included in earnings	(751)	(755)	(935)	(2,170)
Purchases and issuances	5,092	6,763	14,030	18,511
Sales and settlements	(3,817)	(6,230)	(10,700)	(14,549)
Ending balance	7,689	4,960	7,689	4,960
Net change in unrealized gains (losses) relating to items held at end of period	1,508	1,764	1,508	1,764
Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5,828	2,602	4,157	1,654
Change included in earnings	(296)	(166)	(62)	(523)
Purchases and issuances	649	760	2,086	2,065
Sales and settlements	0	0	0	0
Ending balance	6,181	3,196	6,181	3,196
Net change in unrealized gains (losses) relating to items held at end of period	0	0	0	0
Interest rate lock commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1,337	2,580	1,137	1,514
Change included in earnings	(455)	(589)	(873)	(1,647)
Purchases and issuances	4,443	6,003	11,944	16,446
Sales and settlements	(3,817)	(6,230)	(10,700)	(14,549)
Ending balance	1,508	1,764	1,508	1,764
Net change in unrealized gains (losses) relating to items held at end of period	$ 1,508	$ 1,764	$ 1,508	$ 1,764