Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 122,727	$ 123,439
Accumulated Amortization	(89,190)	(84,072)
Valuation Allowance	(431)	(592)
Net Intangible Assets	33,106	38,775
Loan Servicing Rights
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	74,969	72,154
Accumulated Amortization	(56,657)	(51,708)
Valuation Allowance	(431)	(592)
Net Intangible Assets	17,881	19,854
Core Deposits
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	43,384	46,694
Accumulated Amortization	(30,086)	(29,916)
Valuation Allowance	0	0
Net Intangible Assets	13,298	16,778
Other
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	4,374	4,591
Accumulated Amortization	(2,447)	(2,448)
Valuation Allowance	0	0
Net Intangible Assets	$ 1,927	$ 2,143