Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 111,810	$ 112,172
Accumulated Amortization	(81,411)	(75,538)
Valuation Allowance	(231)	(504)
Net Intangible Assets	30,168	36,130
Loan Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	72,024	71,100
Accumulated Amortization	(50,017)	(45,032)
Valuation Allowance	(231)	(504)
Net Intangible Assets	21,776	25,564
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	35,194	35,194
Accumulated Amortization	(29,060)	(27,238)
Valuation Allowance	0	0
Net Intangible Assets	6,134	7,956
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	4,592	5,878
Accumulated Amortization	(2,334)	(3,268)
Valuation Allowance	0	0
Net Intangible Assets	$ 2,258	$ 2,610