Share-Based Compensation - Summary of Total Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock based compensation expense	$ 2,217	$ 1,439	$ 5,618	$ 3,904
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock based compensation expense	316	289	905	683
Restricted Stock or Units Settled in Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock based compensation expense	539	687	1,330	2,214
Restricted Stock Units to be Settled in Cash [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock based compensation expense	$ 1,362	$ 463	$ 3,383	$ 1,007