Stockholders' Equity Share Repurchases (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 2011 Share Repurchase Plan [Member]	Dec. 31, 2011 2011 Share Repurchase Plan [Member]	Dec. 31, 2013 2013 Share Repurchase Plan [Member] [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired			1,984,240	1,022,159
Treasury Stock, Value, Acquired, Cost Method	$ 42,853,000	$ 15,996,000	$ 42,853,000	$ 15,996,000
Treasury Stock Acquired, Average Cost Per Share			$ 21.60	$ 15.65
Stock Repurchase Program, Authorized Amount				$ 100,000,000	$ 100,000,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased				5,000,000	5,000,000