Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			$ 634,604
Other comprehensive income before reclassifications	$ 5,977	$ (2,657)	16,418	$ 9,899
Amounts reclassified from AOCI	564	568	1,127	1,134
Net current-period other comprehensive income	6,541	(2,089)	17,545	11,033
Ending Balance	707,341		707,341
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(86,334)	(75,758)	(96,775)	(88,337)
Other comprehensive income before reclassifications	5,977	(2,648)	16,418	9,931
Net current-period other comprehensive income	5,977	(2,648)	16,418	9,931
Ending Balance	(80,357)	(78,406)	(80,357)	(78,406)
Defined Benefit Pension Plan Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(30,225)	(36,261)	(30,790)	(36,825)
Amounts reclassified from AOCI	567	565	1,132	1,129
Net current-period other comprehensive income	567	565	1,132	1,129
Ending Balance	(29,658)	(35,696)	(29,658)	(35,696)
Cash Flow Hedge Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	98	53	100	74
Other comprehensive income before reclassifications		(9)		(32)
Amounts reclassified from AOCI	(3)	3	(5)	5
Net current-period other comprehensive income	(3)	(6)	(5)	(27)
Ending Balance	95	47	95	47
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(116,461)	(111,966)	(127,465)	(125,088)
Ending Balance	$ (109,920)	$ (114,055)	$ (109,920)	$ (114,055)