Covered Nonaccrual Loans (Detail) (Covered Loans, USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Financing Receivable, Modifications [Line Items]
Nonaccrual loans	$ 12,783	$ 12,783	$ 19,755
Interest income effect
Gross amount of interest that would have been recorded under original terms	961	2,019
Interest included in income	54	163
Net impact on interest income	907	1,856
Commercial
Financing Receivable, Modifications [Line Items]
Nonaccrual loans	8,733	8,733	16,190
Real estate-commercial
Financing Receivable, Modifications [Line Items]
Nonaccrual loans	2,883	2,883	2,074
Home equity
Financing Receivable, Modifications [Line Items]
Nonaccrual loans	1,157	1,157	1,491
All other
Financing Receivable, Modifications [Line Items]
Nonaccrual loans	$ 10	$ 10	$ 0

Financing Receivable, Impaired, Interest Income that would have been recorded

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- Definition

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.

+ Details

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- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5111-111524
-Subparagraph (d)

+ Details

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- Definition

The interest income recognized on a cash-basis method of accounting during the time within that period that the financing receivables were impaired.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5212-111524
-Subparagraph (c)(3)

+ Details

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- Details

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- Definition

Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 114
-Paragraph 20
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher OTS
-Name Federal Regulation (FR)
-Number Title 12
-Chapter V
-Section 563c.102
-Subsection I
-Paragraph 8
-Subparagraph j(ii)
-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 15
-Paragraph 40
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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