Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 199,932	$ 171,769
Accumulated Amortization	(113,113)	(94,696)
Valuation Allowance	(47)	(83)
Net Intangible Assets	86,772	76,990
Loan servicing rights
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	94,827	87,354
Accumulated Amortization	(70,095)	(63,161)
Valuation Allowance	(47)	(83)
Net Intangible Assets	24,685	24,110
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	101,160	80,470
Accumulated Amortization	(40,384)	(29,136)
Valuation Allowance	0	0
Net Intangible Assets	60,776	51,334
Other
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	3,945	3,945
Accumulated Amortization	(2,634)	(2,399)
Valuation Allowance	0	0
Net Intangible Assets	$ 1,311	$ 1,546