Other Comprehensive Income (Loss) - Schedule of Changes in Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Components Of Other Comprehensive Income Loss [Line Items]
Marketable securities, Balance at beginning of period	$ 47,112	$ 154,169
Other comprehensive loss - unrealized losses arising during the year	(1,786)	(83,931)
Marketable securities, Balance at end of period	45,326	70,238
Currency translation, Balance at beginning of period	(154,173)	(133,816)
Other comprehensive loss	(12,959)	(514)
Currency translation, Balance at end of period	(167,132)	(134,330)
Balance at beginning of period	(182,039)	(35,016)
Other comprehensive loss	(14,147)	(84,065)
Balance at end of period	(196,186)	(119,081)
Defined Benefit Pension Plans
Components Of Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(75,260)	(56,644)
Amortization of prior service credit and net losses (gains) included in net periodic pension cost	734	537
Balance at end of period	(74,526)	(56,107)
OPEB
Components Of Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	282	1,275
Amortization of prior service credit and net losses (gains) included in net periodic pension cost	(136)	(157)
Balance at end of period	$ 146	$ 1,118