Restructuring and Other Separation Costs - Schedule of Restructuring Related Activity (Detail) - Severance and Other Employment Expenses [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
2019 Restructuring and Other Separation Costs [Member]
Restructuring Cost And Reserve [Line Items]
Costs incurred	$ 2,566
Liability, ending balance	2,566
2018 Restructuring Program [Member]
Restructuring Cost And Reserve [Line Items]
Liability, beginning balance	537
Payments made	(159)
Liability, ending balance	$ 378