Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Allowance for doubtful accounts on trade receivables	$ 3.1	$ 3.1
Stockholders' deficiency:
Treasury stock, at cost	667,150	532,838
Class B Common Stock
Stockholders' deficiency:
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares issued	3,125,000	3,125,000
Common Stock, shares outstanding	3,125,000	3,125,000
Class A Common Stock
Stockholders' deficiency:
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	900,000,000	900,000,000
Common Stock, shares issued	49,993,559	50,000,497