Fair Value (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Senior secured credit facility | Select
Fair Value
Carrying value	$ 834.3	$ 878.0
Fair value	815.6	823.3
7 5/8% senior subordinated notes | Select
Fair Value
Carrying value	345.0	345.0
Fair value	346.3	326.4
Interest rate of debt (as a percent)	7.625%	7.625%
Senior floating rate notes | Holdings
Fair Value
Carrying value	167.3	167.3
Fair value	$ 160.6	$ 143.9