Commitments And Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Securities held to maturity, mortgaged related securities, pledged	$ 967,400,000	$ 2,900,000,000
Securities held to maturity, other securities, pledged	1,200,000,000	1,700,000,000
Securities available for sale, mortgaged-related securities, pledged	0	11,400,000
Loans pledged to FHLB, collateral for wholesale borrowings	21,500,000,000
Commitments	3,128,329,000
Rental expense under non-cancelable operating lease and license agreements	32,800,000	35,200,000	$ 33,700,000
Rental income on bank-owned properties, netted in occupancy and equipment expense	3,700,000	3,600,000	$ 3,900,000
Bankers acceptance outstanding	151,000
Total loans
Loss Contingencies [Line Items]
Commitments	2,831,824,000	$ 2,600,000,000
Visa Litigation
Loss Contingencies [Line Items]
Fair value contingent obligation to visa U.S.A., based on percentage of membership interest	$ 433,000

Carrying amount as of the balance sheet date of drafts and bills of exchange that have been accepted by the reporting bank, or by others for its own account, as its liability to holders of the drafts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.14)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Fair value portion of arrangements with third parties, including, but not limited to, operating lease arrangement and arrangement in which the entity has agreed to expend funds to procure goods or services, or has agreed to commit resources to supply goods or services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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-Number 210
-Section 03
-Paragraph 19
-Article 7

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Number 210
-Section 03
-Paragraph 17
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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=55761124&loc=SL6224234-111729

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The carrying amount as of the date of the latest financial statement presented of other debt securities classified as held to maturity which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

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The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for FHLB debt obligations, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

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Income earned by providing the use of assets to an outside party in exchange for a payment or series of payments that is nonoperating in nature.

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