Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			$ 740,096
Other comprehensive income before reclassifications	$ (35,012)	$ 5,977	(26,227)	$ 16,418
Amounts reclassified from AOCI	750	564	1,500	1,127
Net current-period other comprehensive income	(34,262)	6,541	(24,727)	17,545
Ending Balance	761,240		761,240
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(61,776)	(86,334)	(70,561)	(96,775)
Other comprehensive income before reclassifications	(35,012)	5,977	(26,227)	16,418
Net current-period other comprehensive income	(35,012)	5,977	(26,227)	16,418
Ending Balance	(96,788)	(80,357)	(96,788)	(80,357)
Defined Benefit Pension Plan Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(28,340)	(30,225)	(29,093)	(30,790)
Amounts reclassified from AOCI	752	567	1,505	1,132
Net current-period other comprehensive income	752	567	1,505	1,132
Ending Balance	(27,588)	(29,658)	(27,588)	(29,658)
Cash Flow Hedge Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	88	98	91	100
Amounts reclassified from AOCI	(2)	(3)	(5)	(5)
Net current-period other comprehensive income	(2)	(3)	(5)	(5)
Ending Balance	86	95	86	95
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(90,028)	(116,461)	(99,563)	(127,465)
Ending Balance	$ (124,290)	$ (109,920)	$ (124,290)	$ (109,920)