Severance and Other Separation Costs - Schedule of Restructuring Program Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2019
Restructuring Cost And Reserve [Line Items]
Severance and other separation costs		$ 1,200	$ 3,800
2020 Restructuring Program [Member]
Restructuring Cost And Reserve [Line Items]
Severance and other separation costs	$ 2,500
Severance and Other Employment Expenses [Member] | 2020 Restructuring Program [Member]
Restructuring Cost And Reserve [Line Items]
Severance and other separation costs	2,468
Payments made	(1,115)
Liability, ending balance	$ 1,353