Supplemental Guarantor and Non-Guarantor Financial Information (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended		0 Months Ended
	Nov. 21, 2012 2020 Notes	Mar. 31, 2013 2020 Notes	Mar. 27, 2013 2021 Notes	Mar. 31, 2013 2021 Notes
Debt instrument
Amount borrowed	$ 500.0		$ 450.0
Interest rate (as a percent)	9.875%	9.875%	8.50%	8.50%