Public Equity Offering (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 10, 2013
Public Equity Offering [Abstract]
Stock Issued During Period, Shares, Issued for Cash	9,775,000
Issuance Of Common Stock Under Public Offering To Underwriters By Company				1,275,000
Payments of Stock Issuance Costs	$ 7,400,000
Proceeds from Issuance of Common Stock	141,700,000	149,069,000	146,510,000
Repayments of Long-term Debt	130,000,000
Proceeds From Public Offering Used to Fund Working Capital	$ 11,700,000