Stock-Based Compensation - Additional Information (Detail)	3 Months Ended
Mar. 31, 2015
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average period for amortization of unrecognized compensation cost	1 year 7 months 6 days
Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average period for amortization of unrecognized compensation cost	2 years 6 months
Stock Appreciation Rights (SARs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average period for amortization of unrecognized compensation cost	1 year 8 months 12 days

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration