Stock-Based Compensation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2014
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average periods for amortization of unrecognizable compensation for compensation arrangements	1 year 2 months 12 days
Stock awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average periods for amortization of unrecognizable compensation for compensation arrangements	1 year 10 months 24 days
Stock appreciation rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average periods for amortization of unrecognizable compensation for compensation arrangements	1 year 3 months 18 days