Subsequent Event (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		0 Months Ended
	Mar. 31, 2013	May 03, 2013 7.50% Convertible Senior Secured Notes due 2019	May 03, 2013 Subsequent events Term loans under secured credit facility	May 03, 2013 Subsequent events 7.50% Convertible Senior Secured Notes due 2019
Subsequent events
Aggregate principal amount of convertible senior secured notes issued	$ 90.0			$ 90.0
Fixed interest rate (as a percent)	7.50%	7.50%		7.50%
Net proceeds from issuance of debt				86.4
Repayment of debt			19.6
Loss on extinguishment of debt			$ 1.2