Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 176,406	$ 171,769
Accumulated Amortization	(108,192)	(94,696)
Valuation Allowance	(64)	(83)
Net Intangible Assets	68,150	76,990
Loan servicing rights
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	91,991	87,354
Accumulated Amortization	(68,225)	(63,161)
Valuation Allowance	(64)	(83)
Net Intangible Assets	23,702	24,110
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	80,470	80,470
Accumulated Amortization	(37,392)	(29,136)
Valuation Allowance	0	0
Net Intangible Assets	43,078	51,334
Other
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	3,945	3,945
Accumulated Amortization	(2,575)	(2,399)
Valuation Allowance	0	0
Net Intangible Assets	$ 1,370	$ 1,546