Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Parent [Member]	Total
Balances at Dec. 31, 2012	$ 1,671,000	$ 207,073,000	$ 1,985,213,000	$ (1,402,097,000)	$ 791,860,000
Comprehensive income:
Net earnings			342,382,000		342,382,000	$ 342,382,000
Cash dividend declared and paid			(52,811,000)		(52,811,000)
Tax benefit of stock options exercised		21,950,000			21,950,000	21,950,000
Purchase of treasury shares				(114,723,000)	(114,723,000)
Share-based compensation		32,354,000			32,354,000	32,354,000
Stock option exercises and restricted share issuances, net of stock repurchased for payroll taxes		(34,782,000)		26,222,000	(8,560,000)
Balances at Dec. 31, 2013	1,671,000	226,595,000	2,274,784,000	(1,490,598,000)	1,012,452,000
Comprehensive income:
Net earnings			374,792,000		374,792,000	374,792,000
Cash dividend declared and paid			(93,604,000)		(93,604,000)
Tax benefit of stock options exercised		16,645,000			16,645,000	16,645,000
Purchase of treasury shares				(125,000,000)	(125,000,000)
Share-based compensation		35,333,000			35,333,000	35,333,000
Stock option exercises and restricted share issuances, net of stock repurchased for payroll taxes		(30,932,000)		14,837,000	(16,095,000)
Balances at Dec. 31, 2014	1,671,000	247,641,000	2,555,972,000	(1,600,761,000)	1,204,523,000	1,204,523,000
Comprehensive income:
Net earnings			427,235,000		427,235,000	427,235,000
Cash dividend declared and paid			(97,364,000)		(97,364,000)
Tax benefit of stock options exercised		12,877,000			12,877,000	12,877,000
Purchase of treasury shares				(262,275,000)	(262,275,000)
Share-based compensation		37,228,000			37,228,000	37,228,000
Stock option exercises and restricted share issuances, net of stock repurchased for payroll taxes		(29,018,000)		7,146,000	(21,872,000)
Balances at Dec. 31, 2015	$ 1,671,000	$ 268,728,000	$ 2,885,843,000	$ (1,855,890,000)	$ 1,300,352,000	$ 1,300,352,000