Activity in Allowance for Losses for Non-Covered Loans and Covered Loans (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	$ 1,677	$ 490
Allowance for Loan Losses, Collectively evaluated for impairment	137,338	136,800
Allowance for Loan Losses, Acquired loans with deteriorated credit quality	54,591	33,323
Allowance for Loan Losses	193,606	170,613
Mortgage Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	1,677	490
Allowance for Loan Losses, Collectively evaluated for impairment	124,017	121,505
Allowance for Loan Losses, Acquired loans with deteriorated credit quality	35,085	14,227
Allowance for Loan Losses	160,779	136,222
Other loan
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Collectively evaluated for impairment	13,321	15,295
Allowance for Loan Losses, Acquired loans with deteriorated credit quality	19,506	19,096
Allowance for Loan Losses	$ 32,827	$ 34,391

A valuation allowance for financing receivables that are expected to be uncollectible.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953423-111524

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The valuation allowance for financing receivables 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

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953423-111524

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953423-111524

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953423-111524

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