Restructuring - Activity in Restructuring Liability Accounts (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 704
Provision, net	173
Usage	(268)
Ending Balance	609
Lease/Rental Terminations [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	704
Usage	(209)
Ending Balance	495
One-Time Employee Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Provision, net	173
Usage	(59)
Ending Balance	$ 114