Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 143,020	$ 123,439
Accumulated Amortization	(93,849)	(84,072)
Valuation Allowance	(289)	(592)
Net Intangible Assets	48,882	38,775
Loan Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	75,932	72,154
Accumulated Amortization	(59,251)	(51,708)
Valuation Allowance	(289)	(592)
Net Intangible Assets	16,392	19,854
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	62,714	46,694
Accumulated Amortization	(31,934)	(29,916)
Valuation Allowance	0	0
Net Intangible Assets	30,780	16,778
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	4,374	4,591
Accumulated Amortization	(2,664)	(2,448)
Valuation Allowance	0	0
Net Intangible Assets	$ 1,710	$ 2,143