Loan Modifications Determined to be Troubled Debt Restructuring (Detail) (Residential Loans, USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013 Contract	Jun. 30, 2012 Contract	Jun. 30, 2013 Contract	Jun. 30, 2012 Contract
Residential Loans
Financing Receivable, Modifications [Line Items]
Number of modifications	4	2	7	6
Pre-modification outstanding recorded investment	$ 1,031	$ 884	$ 1,795	$ 2,672
Post-modification outstanding recorded investment	1,145	626	1,941	2,425
Loan modification effect on net interest income after provision and other MVA	(140)	(118)	(309)	(597)
Number of modifications	1	2	3	4
Recorded investment	$ 178	$ 603	$ 587	$ 1,702

Financing Receivable Modifications Effect on Net Interest Income

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524

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Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953682-111524

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Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

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