Income Taxes - Schedule of Changes in Unrecognized Tax Benefit (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 2,297us-gaap_UnrecognizedTaxBenefits	$ 1,356us-gaap_UnrecognizedTaxBenefits	$ 2,194us-gaap_UnrecognizedTaxBenefits
Additions based on tax positions related to the current year	668	668	214
Additions for tax positions for prior years	31	538	68
Reductions for tax positions for prior years	(22)	0	(300)
Reduction to unrecognized tax benefits as a result of a lapse of the applicable statute of limitations	171	265	820
Ending Balance	$ 2,803us-gaap_UnrecognizedTaxBenefits	$ 2,297us-gaap_UnrecognizedTaxBenefits	$ 1,356us-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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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- Definition

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

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-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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