Earnings per Share Earnings per Share (Textuals) (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Earnings Per Share [Abstract]
Convertible senior subordinated notes	$ 57,500,000	$ 57,500,000	$ 0
Debt Instrument, Convertible, Conversion Ratio	42.0159
Debt Instrument Convertible Principal Amount Used In Conversion Rate Calculation	1,000	1,000
Debt Instrument, Convertible, Conversion Price	$ 23.80	$ 23.80
Stock Issued During Period, Shares, Other	2,400,000
Stock Issued During Period, Shares, New Issues	2,530,000
StockIssuedDuringPeriodPricePerShare	$ 17.63
Proceeds from Issuance of Common Stock	$ 42,100,000	$ 42,085,000	$ 0	$ 0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		739,296