Shareholders' Equity (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 plans	Dec. 31, 2011	Dec. 31, 2010
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	$ 200,000,000
Total stock repurchased under plan, shares	4,100,000
Total stock repurchased under plan, value	95,100,000
Remaining authorized repurchase amount	104,900,000
Number of share repurchased	100,000	700,000	1,200,000
Repurchase of treasury stock	(3,923,000)	(15,021,000)	(22,977,000)
Number of shares reserved for share-based compensation plans	7,000,000
Number of share-based compensation plans	3
Number of shares available for grant	1,400,000
Vesting term	5 years
Stock-based compensation	5,653,000	5,240,000	4,223,000
Tax benefit from stock-based compensation	2,100,000	1,900,000	1,600,000
Proceeds from stock options exercised	$ 9,600,000	$ 5,600,000	$ 2,000,000
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