Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (Losses) (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	$ (204,606)	$ (190,486)	$ (154,870)
Other comprehensive income before reclassifications (net of tax)	55,309	(28,408)	(43,926)
Amounts reclassified from accumulated other comprehensive income (net of tax)	8,622	14,288	8,310
Net current period other comprehensive income (loss)	63,931	(14,120)	(35,616)
Ending Balance	(140,675)	(204,606)	(190,486)
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(100,448)	(73,041)	(34,224)
Other comprehensive income before reclassifications (net of tax)	58,609	(27,407)	(38,817)
Net current period other comprehensive income (loss)	58,609	(27,407)	(38,817)
Ending Balance	(41,839)	(100,448)	(73,041)
Unrealized Gain (Loss) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	1,500	(225)	2,356
Other comprehensive income before reclassifications (net of tax)	(5,182)	1,247	1,620
Amounts reclassified from accumulated other comprehensive income (net of tax)	(410)	478	(4,201)
Net current period other comprehensive income (loss)	(5,592)	1,725	(2,581)
Ending Balance	(4,092)	1,500	(225)
Change in Pensions [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(110,656)	(120,714)	(120,260)
Other comprehensive income before reclassifications (net of tax)	2,981	(4,334)	(12,995)
Amounts reclassified from accumulated other comprehensive income (net of tax)	9,380	14,392	12,541
Net current period other comprehensive income (loss)	12,361	10,058	(454)
Ending Balance	(98,295)	(110,656)	(120,714)
Change in Other Postretirement Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	4,998	3,494	(2,742)
Other comprehensive income before reclassifications (net of tax)	(1,099)	2,086	6,266
Amounts reclassified from accumulated other comprehensive income (net of tax)	(348)	(582)	(30)
Net current period other comprehensive income (loss)	(1,447)	1,504	6,236
Ending Balance	$ 3,551	$ 4,998	$ 3,494