Income Taxes - Summary of Changes in 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]
Balance at the beginning of the year	$ 270us-gaap_UnrecognizedTaxBenefits	$ 442us-gaap_UnrecognizedTaxBenefits	$ 311us-gaap_UnrecognizedTaxBenefits
Gross increases for tax positions taken in the current year	0	8	233
Gross increases for tax positions taken in prior years	2	12	18
Gross decreases in tax positions due to lapse in statute of limitations	(61)	0	(120)
Gross decreases for tax positions taken in prior years	(17)	(192)	0
Gross decreases for tax settlements with taxing authorities	(142)	0	0
Balance at the end of the year	$ 52us-gaap_UnrecognizedTaxBenefits	$ 270us-gaap_UnrecognizedTaxBenefits	$ 442us-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

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-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.

+ References

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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.

+ References

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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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