Goodwill and Other Intangible Assets - Schedule of Mortgage Servicing Rights at Carrying Value (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 137,774	$ 129,163
Accumulated Amortization	(48,034)	(53,006)
Net Carrying Amount	89,740	76,157
Mortgage servicing rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,030	9,588
Accumulated Amortization	(4,128)	(3,931)
Net Carrying Amount	$ 5,902	$ 5,657