Shared-Based Compensation - Components of Share-Based Compensation Expense by Type of Award (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ (124)	$ 289	$ 1,855	$ 2,623
Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	371	173	732	531
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	446	388	1,407	1,244
Performance Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	334	530	991	1,650
Change in Accounting Method Accounted for as Change in Estimate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ (1,275)	$ (802)	$ (1,275)	$ (802)