Summary of Stock Awards Granted (Parenthetical) (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vest period		4 years	4 years	4 years	4 years
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards with performance conditions	[1]	65,000		181,783	6,000
Restricted Stock Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards with performance conditions				97,500
Stock-based compensation related to grants		$ 3,300,000		$ 3,300,000
Restricted Stock Awards [Member] | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards with performance conditions				65,000

[1] In September 2015, the Company granted certain employees restricted stock awards (“RSAs”) with performance conditions. If certain performance milestones are achieved within the required time frame, the number of RSAs with performance conditions may be increased from 65,000 to 97,500 shares. As a result, the Company may recognize up to $3.3 million of stock-based compensation related to these grants when performance is deemed probable.