Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, beginning balance	$ 11,851us-gaap_UnrecognizedTaxBenefits	$ 7,064us-gaap_UnrecognizedTaxBenefits	$ 9,875us-gaap_UnrecognizedTaxBenefits
Additions based on tax positions related to the current year	638	4,853	432
Additions for tax positions of prior years	121	545	96
Reductions for tax positions of prior years	(3,691)	(538)	(24)
Settlement of tax audits	(258)	0	(768)
Reductions due to lapsed statute of limitations	(2,102)	(73)	(2,547)
Unrecognized tax benefits, ending balance	$ 6,559us-gaap_UnrecognizedTaxBenefits	$ 11,851us-gaap_UnrecognizedTaxBenefits	$ 7,064us-gaap_UnrecognizedTaxBenefits

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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