Treasury Stock (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended		20 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method	$ 90,000	$ 353,000
Stock Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount			300,000,000
Treasury stock, shares, acquired (in shares)	0	1.0	45.0
Treasury Stock, Value, Acquired, Cost Method		4,500,000	208,400,000
Share Repurchase Program Commission Incurred			900,000
Treasury Stock Acquired, Average Cost Per Share		$ 4.62
Accrued Liability for Repurchased but Unpaid Treasury Stock	0		0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	91,600,000
Maximum [Member] | Stock Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Share Repurchase Program Commission Incurred		$ 100,000