Other Comprehensive Income - Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Components of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance			$ (720,211)	$ (397,655)
Other comprehensive income (loss) before reclassifications, net of tax			(100,994)	38,639
Amounts reclassified from accumulated other comprehensive loss, net of tax			11,704	7,601
Net current period other comprehensive income (loss)	$ 18,181	$ 42,347	(89,290)	46,240
Ending balance	(809,501)	(351,415)	(809,501)	(351,415)
Pension and Other Post-Retirement Benefits [Member]
Components of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance			(533,213)	(360,036)
Amounts reclassified from accumulated other comprehensive loss, net of tax			11,704	7,601
Net current period other comprehensive income (loss)			11,704	7,601
Ending balance	(521,509)	(352,435)	(521,509)	(352,435)
Foreign Currency Translation [Member]
Components of Accumulated Other Comprehensive Loss [Line Items]
Beginning balance			(186,998)	(37,619)
Other comprehensive income (loss) before reclassifications, net of tax			(100,994)	38,639
Net current period other comprehensive income (loss)			(100,994)	38,639
Ending balance	$ (287,992)	$ 1,020	$ (287,992)	$ 1,020