Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 634,604
Other comprehensive income before reclassifications	25,632	$ (4,639)	$ (44,161)
Amounts reclassified from AOCI	2,270	2,262	3,018
Net current period other comprehensive income	27,902	(2,377)	(41,143)
Ending Balance	740,096	634,604
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(96,775)	(88,337)	(42,914)
Other comprehensive income before reclassifications	26,214	(8,438)	(45,423)
Net current period other comprehensive income	26,214	(8,438)	(45,423)
Ending Balance	(70,561)	(96,775)	(88,337)
Defined Benefit Pension Plan Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(30,790)	(36,825)	(41,149)
Other comprehensive income before reclassifications	(582)	3,818	1,311
Amounts reclassified from AOCI	2,279	2,217	3,013
Net current period other comprehensive income	1,697	6,035	4,324
Ending Balance	(29,093)	(30,790)	(36,825)
Cash Flow Hedge Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	100	74	118
Other comprehensive income before reclassifications		(19)	(49)
Amounts reclassified from AOCI	(9)	45	5
Net current period other comprehensive income	(9)	26	(44)
Ending Balance	91	100	74
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(127,465)	(125,088)	(83,945)
Ending Balance	$ (99,563)	$ (127,465)	$ (125,088)