Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 211,784	$ 208,255
Accumulated Amortization	(143,738)	(136,941)
Valuation Allowance	(74)	(865)
Net Intangible Assets	67,972	70,449
Loan servicing rights
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	106,679	103,150
Accumulated Amortization	(84,163)	(80,340)
Valuation Allowance	(74)	(865)
Net Intangible Assets	22,442	21,945
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	101,160	101,160
Accumulated Amortization	(56,669)	(53,747)
Valuation Allowance	0	0
Net Intangible Assets	44,491	47,413
Other
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	3,945	3,945
Accumulated Amortization	(2,906)	(2,854)
Valuation Allowance	0	0
Net Intangible Assets	$ 1,039	$ 1,091