Summary of Significant Accounting Policies - Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ (720,211)	$ (397,655)
Other comprehensive income (loss) before reclassifications, net of tax	(233,655)	(342,600)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	23,248	20,044
Other comprehensive (loss) income, net of tax	(210,407)	(322,556)	$ 103,837
Ending balance	(930,618)	(720,211)	(397,655)
Pension Benefits [Member]
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(532,069)	(359,079)
Other comprehensive income (loss) before reclassifications, net of tax	(25,558)	(193,182)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	23,412	20,192
Other comprehensive (loss) income, net of tax	(2,146)	(172,990)
Ending balance	(534,215)	(532,069)	(359,079)
Other Post-Retirement Benefits [Member]
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(1,144)	(957)
Other comprehensive income (loss) before reclassifications, net of tax	(111)	(39)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(164)	(148)
Other comprehensive (loss) income, net of tax	(275)	(187)
Ending balance	(1,419)	(1,144)	(957)
Foreign Currency Translation [Member]
Components Of Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(186,998)	(37,619)
Other comprehensive income (loss) before reclassifications, net of tax	(207,986)	(149,379)
Other comprehensive (loss) income, net of tax	(207,986)	(149,379)
Ending balance	$ (394,984)	$ (186,998)	$ (37,619)