Stock-Based Compensation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 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 2 months 12 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
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 3 months 18 days