Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Feb. 10, 2012	Sep. 30, 2001
Common Stock Repurchase Authorized
Stock Repurchase Shares Authorized	2,200,000			5,000,000	15,400,000
Treasury Stock, Shares, Acquired	4,200,000	0	3,500,000
Repurchases of Common Stock	$ 56,350	$ 0	$ 45,360