Common Stock (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Repurchase Program [Line Items]
Treasury stock, shares acquired		1,377,798	843,400
Treasury Stock, Value, Acquired, Cost Method		$ 119,600,000	$ 71,300,000
Repurchase program, remaining authorized repurchase amount	100,000,000
Common Stock, Dividends, Per Share, Cash Paid	$ 0.00	$ 5.00	$ 0.00
Special Cash Dividend	0	100,385,000	0
Outstanding common shares receiving dividends		20,076,762
Restricted Stock [Member]
Stock Repurchase Program [Line Items]
Outstanding common shares receiving dividends		171,562
Dividends, Cash		$ 900,000