Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Type (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Stock Based Compensation [Line Items]
Total	$ 433	$ 918	$ 1,996	$ 3,246
Service-based Awards [Member]
Stock Based Compensation [Line Items]
Total	462	472	1,749	1,942
Performance-based Awards - Short-term Incentive Plan [Member]
Stock Based Compensation [Line Items]
Total	0	361	0	990
Performance-based Awards - Long-term Incentive Plan [Member]
Stock Based Compensation [Line Items]
Total	(88)	56	67	170
Employee Stock Purchase Plan [Member]
Stock Based Compensation [Line Items]
Total	59	29	180	143
Stock Options [Member]
Stock Based Compensation [Line Items]
Total	$ 0	$ 0	$ 0	$ 1