Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Allowance for doubtful accounts on trade receivables	$ 3.9	$ 3.2
Class B Common Stock [Member]
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 [Member]
Stockholders' deficiency:
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	900,000,000	900,000,000
Common Stock, shares issued	49,986,651	49,986,651
Treasury stock, at cost	750,900	671,271