Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
AOCI Attributable to Parent [Roll Forward]
Beginning balance, January 1			$ 3,193,728
Other comprehensive income before reclassifications, net of tax			80,177	$ 38,944
Amounts reclassified from accumulated other comprehensive loss, net of tax			11,455	9,509
Total other comprehensive income (loss)	$ 28,880	$ (19,646)	91,632	48,453
Ending balance, June 30	3,288,124		3,288,124
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			11,455	9,509
Total other comprehensive income (loss)			11,455	9,509
Ending balance, June 30	(597,625)	(526,125)	(597,625)	(526,125)
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			80,177	38,944
Amounts reclassified from accumulated other comprehensive loss, net of tax			0	0
Total other comprehensive income (loss)			80,177	38,944
Ending balance, June 30	(323,764)	(356,040)	(323,764)	(356,040)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance, January 1			(1,013,021)	(930,618)
Ending balance, June 30	$ (921,389)	$ (882,165)	$ (921,389)	$ (882,165)