Equity Offering (Details) (USD $)	12 Months Ended			3 Months Ended			3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Senior secured notes [Member]	Jun. 30, 2012 Senior secured notes [Member]	Dec. 29, 2009 Senior secured notes [Member]	Sep. 30, 2013 Common Stock [Member]	Jun. 30, 2012 Common Stock [Member]	Sep. 16, 2013 Common Stock [Member]	May 08, 2012 Common Stock [Member]
Equity Offering [Line Items]
Stock Issued During Period, Shares, New Issues							5,175,000	4,000,000
Stock Issued During Period, Value, Per Share Offering Price									$ 35.40	$ 20.75
Stock Issuance Costs							$ 8,500,000	$ 4,000,000
Proceeds from sale of common stock	174,670,000	79,040,000	0				174,700,000	79,000,000
Proceeds Used for Early Extinguishment of Debt					54,900,000
Debt Instrument, Interest Rate, Stated Percentage						9.75%
Extinguishment of Debt, Amount				$ 200,000,000	$ 50,000,000