Transfers and Servicing of Financial Assets (Including Mortgage Banking Activity) - Schedule of Mortgage Servicing Rights at Carrying Values (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 57,665	$ 46,754
Accumulated Amortization	(37,304)	(31,415)
Net Carrying Amount	20,361us-gaap_FiniteLivedIntangibleAssetsNet	15,339us-gaap_FiniteLivedIntangibleAssetsNet
Mortgage Servicing Rights [Member]
Acquired Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	4,751	2,146
Accumulated Amortization	(1,253)	(638)
Net Carrying Amount	$ 3,498	$ 1,508

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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