Unaudited Condensed Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Total	Common shares	Treasury Shares	Accumulated Other Comprehensive Income	Retained Earnings
Balance, at beginning of period at Dec. 31, 2013	$ 3,519,826	$ 418,988	$ (79,992)	$ 0	$ 3,180,830
Net income	328,835				328,835
Dividends	(38,345)				(38,345)
Stock compensation	11,978		14,734		(2,756)
Share repurchases	(139,532)		(139,532)
Shares cancelled	0	(16,081)	139,532		(123,451)
Balance, at end of period at Jun. 30, 2014	3,682,762	402,907	(65,258)	0	3,345,113
Balance, at beginning of period at Dec. 31, 2014	3,778,291	408,020	(143,075)	0	3,513,346
Net income	133,814				133,814
Dividends	(45,114)				(45,114)
Stock compensation	6,383		15,458		(9,075)
Share repurchases	(245,301)		(245,301)
Shares cancelled	0	(21,318)	213,732		(192,414)
Foreign currency translation adjustment	(3,272)			(3,272)
Balance, at end of period at Jun. 30, 2015	$ 3,624,801	$ 386,702	$ (159,186)	$ (3,272)	$ 3,400,557