Shareholders' Equity (Details) (USD $)	1 Months Ended	12 Months Ended
	Oct. 31, 2011	Dec. 31, 2011 plans	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2005
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized		500,000	500,000
Preferred stock, par value (per share)		$ 0.01	$ 0.01
Share authorized under repurchase program					$ 100,000,000
Additional shares authorized under repurchase program	100,000,000
Stock repurchased during period, shares		4,000,000
Stock repurchased during period, value		91,200,000
Remaining authorized repurchase amount		108,800,000
Number of share repurchased		700,000	1,200,000
Repurchase of treasury stock		(15,021,000)	(22,977,000)
Repurchase of common stock		(15,021,000)	(22,977,000)	0
Number of shares reserved for share-based compensation plans		6,000,000
Number of share-based compensation plans		3
Number of shares available for grant		700,000
Exercisable term		5 years
Stock-based compensation		5,240,000	4,223,000	4,308,000
Tax benefit from stock options exercised		1,900,000	1,600,000	1,300,000
Proceeds from stock options exercised		5,600,000	2,000,000	700,000
Stock Options and Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration from date of grant		10 years
Selling and Marketing Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation		$ 5,200,000	$ 4,200,000	$ 4,300,000