Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
AOCI Attributable to Parent [Roll Forward]
Beginning balance, January 1	$ 3,193,728
Other comprehensive income before reclassifications, net of tax	57,020	$ 63,366
Amounts reclassified from accumulated other comprehensive loss, net of tax	5,732	4,733
Total other comprehensive income (loss)	62,752	68,099
Ending balance, March 31	3,218,973
Pension and Other Post-Retirement Benefits [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance, January 1	(609,080)	(535,634)
Other comprehensive income before reclassifications, net of tax	0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax	5,732	4,733
Total other comprehensive income (loss)	5,732	4,733
Ending balance, March 31	(603,348)	(530,901)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance, January 1	(403,941)	(394,984)
Other comprehensive income before reclassifications, net of tax	57,020	63,366
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0
Total other comprehensive income (loss)	57,020	63,366
Ending balance, March 31	(346,921)	(331,618)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance, January 1	(1,013,021)	(930,618)
Ending balance, March 31	$ (950,269)	$ (862,519)