Other Comprehensive Income (Loss) - Schedule of Changes in Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Components Of Other Comprehensive Income Loss [Line Items]
Marketable securities, Balance at beginning of period	$ 154,169	$ 105,419
Marketable securities, Unrealized gain (loss) arising during the year	(83,931)	33,901
Marketable securities, Balance at end of period	70,238	139,320
Currency translation, Balance at beginning of period	(133,816)	(135,165)
Other comprehensive loss	(514)	(5,390)
Currency translation, Balance at end of period	(134,330)	(140,555)
Balance at beginning of period	(35,016)	(95,253)
Total other comprehensive income (loss)	(84,065)	29,066
Balance at end of period	(119,081)	(66,187)
Defined Benefit Pension Plans
Components Of Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(56,644)	(66,402)
Defined benefit pension plans/ Other postretirement benefit plans	537	699
Balance at end of period	(56,107)	(65,703)
OPEB
Components Of Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	1,275	895
Defined benefit pension plans/ Other postretirement benefit plans	(157)	(144)
Balance at end of period	$ 1,118	$ 751