Additional Information Regarding Methods Used to Evaluate Loan Portfolio for Impairment (Detail) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 29,850,504	$ 29,041,595
Other loan \| Additional Information Loan Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Individually evaluated for impairment	10,224	12,929
Loans receivable, Collectively evaluated for impairment	659,103	714,293
Loans receivable, Loans acquired with deteriorated credit quality	369,621	423,420
Loans receivable	1,038,948	1,150,642
Additional Information Loan Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Individually evaluated for impairment	405,345	760,798
Loans receivable, Collectively evaluated for impairment	24,727,672	22,953,877
Loans receivable, Loans acquired with deteriorated credit quality	3,873,294	4,297,869
Loans receivable	29,006,311	28,012,544
Additional Information Loan Portfolio \| Mortgage Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, Individually evaluated for impairment	395,121	747,869
Loans receivable, Collectively evaluated for impairment	24,068,569	22,239,584
Loans receivable, Loans acquired with deteriorated credit quality	3,503,673	3,874,449
Loans receivable	$ 27,967,363	$ 26,861,902

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The amount of the recorded investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, accounts receivable (with terms exceeding one year), notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Receivable

-URI http://asc.fasb.org/extlink&oid=6953735

+ Details

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- Definition

The balance of financing receivables that were acquired with deteriorated credit quality.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953423-111524

-Subparagraph (h)

+ Details

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

+ Details

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- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

+ Details

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