Non-operating Expense (Details) (USD $) In Millions, unless otherwise specified			1 Months Ended		12 Months Ended		1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012 6.75% senior subordinated notes due 2015	Feb. 28, 2011 6.75% senior subordinated notes due 2015	Dec. 31, 2012 6.75% senior subordinated notes due 2015	Dec. 31, 2011 6.75% senior subordinated notes due 2015	Jul. 31, 2010 Senior Secured Credit Facility
Other Non-Operating Expense
Senior subordinated notes redeemed			$ 73.5	$ 150.0
Face value				225
Interest rate (as a percent)	6.75%	6.75%	6.75%	6.75%	6.75%
Call premium (as a percent)			1.25%	2.25%
Pre-tax charge incurred on call premium					1.1	4.9
Amortization of deferred financing cost							$ 6.8