Income Taxes - Additional Information (Detail) (USD $)	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011
Income Tax Contingency
Refund of Federal Tax and Interest	$ 1,626,000	$ 1,060,000
Consolidated overall estimated effective income tax rate	23.00%
Refund received on Settlement with Taxing Authority		1,730,000
Unrecognized tax benefits that would impact effective tax rate	$ 5,876,000
Estimated Effective Income Tax Rate
Income Tax Contingency
Consolidated overall estimated effective income tax rate	21.10%

Expected Annual Income Tax Rate

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- Definition

Proforma Consolidated Overall Estimated Effective Income Tax Rate Excluding Discrete Event

+ References

No definition available.

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- Definition

The amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)

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- Definition

The amount of cash received during the period as refunds for the overpayment of taxes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 29

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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- Definition

The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

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-Paragraph 15A

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-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 48

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-Subparagraph b

-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.

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