Changes in Accumulated Other Comprehensive Loss by Component - Cumulative Other Comprehensive Loss in Accompanying Consolidated Statements of Equity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,076,014
Other comprehensive (loss) income before reclassifications	42,768	$ (95,541)
Foreign currency translation effect	(7,855)	13,152
Income tax effect	2,014	11,711
Cash flow hedges	3,619	100
Amortization of prior service credit	(566)	(566)	$ (566)
Amortization of actuarial losses	42,570	43,624	46,736
Pension settlement charges		12,262
Income tax effect	(15,877)	(20,126)
Other comprehensive (loss) income	66,673	(35,384)
Ending balance	1,127,096	1,076,014
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(75,415)	(22,034)
Other comprehensive (loss) income before reclassifications	35,475	(53,381)
Foreign currency translation effect	0	0
Income tax effect	0	0
Cash flow hedges	0	0
Amortization of prior service credit	0	0
Amortization of actuarial losses	0	0
Pension settlement charges		0
Income tax effect	0	0
Other comprehensive (loss) income	35,475	(53,381)
Ending balance	(39,940)	(75,415)	(22,034)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1,967	3,454
Other comprehensive (loss) income before reclassifications	(6,092)	(2,471)
Foreign currency translation effect	0	0
Income tax effect	1,823	941
Cash flow hedges	3,619	100
Amortization of prior service credit	0	0
Amortization of actuarial losses	0	0
Pension settlement charges		0
Income tax effect	(968)	(57)
Other comprehensive (loss) income	(1,618)	(1,487)
Ending balance	349	1,967	3,454
Post- retirement Benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(471,703)	(491,187)
Other comprehensive (loss) income before reclassifications	13,385	(39,689)
Foreign currency translation effect	(7,855)	13,152
Income tax effect	191	10,770
Cash flow hedges	0	0
Amortization of prior service credit	(566)	(566)
Amortization of actuarial losses	42,570	43,624
Pension settlement charges		12,262
Income tax effect	(14,909)	(20,069)
Other comprehensive (loss) income	32,816	19,484
Ending balance	(438,887)	(471,703)	(491,187)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(545,151)	(509,767)
Ending balance	$ (478,478)	$ (545,151)	$ (509,767)