CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Class A Ordinary Shares/ Common stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury shares [Member]	Accumulated other comprehensive income (loss) [Member]
Balance at Dec. 31, 2011	$ 4,325,987	$ 15,947	$ 1,478,233	$ 3,186,362	$ (128,884)	$ (225,671)
Balance (in shares) at Dec. 31, 2011		123,581
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net shares issued (acquired) under share-based compensation plans	(3,636)	65	(21,212)		17,511
Net shares issued (acquired) under share-based compensation plans (in shares)		578
Share-based compensation	23,018		23,018
Excess tax benefit from share-based compensation plans	1,164		1,164
Retirement benefit adjustments, net of taxes	4,589					4,589
Cancelation of treasury shares	0	(419)	(109,068)		109,487
Other	0
Other (in shares)		52
Net income	180,602			180,602
Balance at Dec. 31, 2012	4,531,724	15,593	1,372,135	3,366,964	(1,886)	(221,082)
Balance (in shares) at Dec. 31, 2012		124,211
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net shares issued (acquired) under share-based compensation plans	(1,742)	4	2,330		(4,076)
Net shares issued (acquired) under share-based compensation plans (in shares)		26
Share-based compensation	27,056		27,056
Excess tax benefit from share-based compensation plans	3,690		3,690
Retirement benefit adjustments, net of taxes	78,637					78,637
Other	1,820		1,820
Other (in shares)		0
Net income	252,576			252,576
Balance at Dec. 31, 2013	4,893,761	15,597	1,407,031	3,619,540	(5,962)	(142,445)
Balance (in shares) at Dec. 31, 2013		124,237
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net shares issued (acquired) under share-based compensation plans	(455)	7	1,566		(2,028)
Net shares issued (acquired) under share-based compensation plans (in shares)		327
Share-based compensation	28,445		28,445
Excess tax benefit from share-based compensation plans	(132)		(132)
Retirement benefit adjustments, net of taxes	(77,469)					(77,469)
Dividends	(37,695)		0	(37,695)	0	0
Other	(204)		0			(204)
Net income	(114,852)			(114,852)
Balance at Dec. 31, 2014	$ 4,691,399	$ 15,604	$ 1,436,910	$ 3,466,993	$ (7,990)	$ (220,118)
Balance (in shares) at Dec. 31, 2014		124,564