Long-term Debt (Details 5) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Sep. 30, 2011
Long-term Debt
Interest expense	$ 12,600,000	$ 17,100,000
Non-cash interest expense	3,049,000	3,237,000
Capitalized interest costs	100,000	0
Interest income			$ 0	$ 100,000
Weighted average interest rate (as a percent)	6.90%		6.90%		6.80%