Consolidated Statements Of Shareholders' Equity (USD $) In Thousands		Total	Share Capital	Additional Paid-In Capital	Treasury Shares	Accumulated Other Comprehensive Income	Retained Earnings
Balance, at beginning of period at Dec. 31, 2011		$ 3,149,022	$ 557,153	$ 78,225	$ (136,590)	$ 14,484	$ 2,635,750
Net income		493,007					493,007
Dividends — par value reduction		(53,523)	(53,523)
Other comprehensive loss		(14,484)				(14,484)
Stock compensation	[1]	16,255		(27,099)	43,354
Share repurchases		(263,942)			(263,942)
Shares cancelled		0	(48,650)	(51,126)	243,360		(143,584)
Balance, at end of period at Dec. 31, 2012		3,326,335	454,980	0	(113,818)	0	2,985,173
Net income		417,880					417,880
Dividends — par value reduction		(12,982)	(12,982)
Dividends		(50,791)					(50,791)
Other comprehensive loss		0
Stock compensation	[1]	14,070		0	31,946		(17,876)
Share repurchases		(174,686)			(174,686)
Shares cancelled		0	(23,010)	0	176,566		(153,556)
Balance, at end of period at Dec. 31, 2013		3,519,826	418,988	0	(79,992)	0	3,180,830
Net income		490,259					490,259
Dividends		(81,686)					(81,686)
Other comprehensive loss		0
Stock compensation	[1]	25,265		0	19,638		5,627
Share repurchases		(175,373)			(175,373)
Shares cancelled		0	(10,968)	0	92,652		(81,684)
Balance, at end of period at Dec. 31, 2014		$ 3,778,291	$ 408,020	$ 0	$ (143,075)	$ 0	$ 3,513,346

[1] Includes stock compensation expense for the period and shares issued out of treasury for awards exercised or vested. See note 2(o) to the notes to the consolidated financial statements.