CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income	Treasury Stock
Beginning Balance at Dec. 31, 2009	$ 2,081,700	$ 1,808	$ 781,635	$ 1,901,853	$ 14,996	$ (618,592)
Beginning Balance (in shares) at Dec. 31, 2009		180,829,000
Comprehensive income:
Net income	63,088			63,088
Foreign currency translation adjustment, net of tax of $0 in 2011 and $2,814 in 2010	4,650				4,650
Total comprehensive income	67,738			63,088	4,650
Issuance of restricted stock (in shares)		646,000
Issuance of restricted stock		6	(6)
Vesting of stock unit awards (in shares)		7,000
Forfeitures of restricted stock (in shares)		(54,000)
Exercise of stock options (in shares)		34,000
Exercise of stock options	290		290
Stock-based compensation	11,881		11,881
Tax expense related to stock-based compensation	(2,535)		(2,535)
Payment of cash dividends	(23,087)			(23,087)
Purchases of treasury stock	(1,848)					(1,848)
Ending Balance at Sep. 30, 2010	2,134,139	1,814	791,265	1,941,854	19,646	(620,440)
Ending Balance (in shares) at Sep. 30, 2010		181,462,000
Beginning Balance at Dec. 31, 2010	2,187,607	1,815	796,641	1,987,999	21,597	(620,445)
Beginning Balance (in shares) at Dec. 31, 2010	181,537,568	181,538,000
Comprehensive income:
Net income	234,818			234,818
Foreign currency translation adjustment, net of tax of $0 in 2011 and $2,814 in 2010	(3,460)				(3,460)
Total comprehensive income	231,358			234,818	(3,460)
Issuance of restricted stock (in shares)		767,000
Issuance of restricted stock		8	(8)
Vesting of stock unit awards (in shares)		10,000
Forfeitures of restricted stock (in shares)		(44,000)
Exercise of stock options (in shares)	838,307	838,000
Exercise of stock options	14,040	8	14,032
Stock-based compensation	15,366		15,366
Tax benefit related to stock-based compensation	5,838		5,838
Payment of cash dividends	(23,257)			(23,257)
Purchases of treasury stock	(4,219)					(4,219)
Ending Balance at Sep. 30, 2011	$ 2,426,733	$ 1,831	$ 831,869	$ 2,199,560	$ 18,137	$ (624,664)
Ending Balance (in shares) at Sep. 30, 2011	183,108,650	183,109,000