Business Restructuring - Reconciliation of Restructuring Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended					9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	[1]	Sep. 30, 2018	Sep. 30, 2017	[1]
Restructuring Cost And Reserve [Line Items]
Expense recognized	$ 1,715			$ 426		$ 2,346	$ 1,798
Canada [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring liability	452	$ 493	$ 691			691
Expense recognized	305	273	358
Amounts paid	(367)	(305)	(549)
Foreign currency translation	7	(9)	(7)
Restructuring liability	397	452	493			397
Canada [Member] | Termination Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring liability	363	449	592			592
Amounts paid	(61)	(79)	(140)
Foreign currency translation	6	(7)	(3)
Restructuring liability	308	363	449			308
Canada [Member] | Other Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring liability	89	44	99			99
Expense recognized	305	273	358
Amounts paid	(306)	(226)	(409)
Foreign currency translation	1	(2)	(4)
Restructuring liability	$ 89	$ 89	$ 44			$ 89

[1] The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost