Long-term Debt - Senior secured notes (Details) (Senior secured notes [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2009	Dec. 14, 2012 Prior to December 15, 2013 [Member]	Dec. 31, 2012 Prior to December 15, 2013 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	$ 200.0	$ 50.0
Debt Instrument, Face Amount				250.0
Debt Instrument, Discount				5.0
Debt redeemed, % of principal					35.00%
Debt outstanding, % of principal					65.00%
Proceeds Used for Early Extinguishment of Debt		54.9
Long-term Debt, Redemption Price, % of principal amount		109.75%			109.75%	100.00%
Non-cash Debt Extinguishment Costs			8.1
Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction			$ 35.7