Geographic Information for Long-Lived Assets and Revenues in United States and other Countries (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Revenues	$ 27,645	$ 43,505	$ 43,099	$ 47,458	$ 49,570	$ 53,819	$ 57,989	$ 49,367	$ 161,707	$ 210,745
Reportable Geographical Components
Long-lived assets:
Long-lived assets	78,021				278,813				78,021	278,813
Revenues:
Revenues									161,707	210,745
Reportable Geographical Components | UNITED STATES
Long-lived assets:
Long-lived assets	76,424				272,903				76,424	272,903
Revenues:
Revenues									118,604	171,167
Reportable Geographical Components | International
Long-lived assets:
Long-lived assets	$ 1,597				$ 5,910				1,597	5,910
Reportable Geographical Components | CANADA
Revenues:
Revenues									2,479	6,086
Reportable Geographical Components | Other International
Revenues:
Revenues									$ 40,624	$ 33,492