CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010	May 18, 2009
CME Ltd. shareholders' equity:
Preferred stock, shares outstanding (in shares)	0	0
Preferred stock, par value (in dollars per share)	$ 0.08	$ 0.08
Common Class A [Member]
CME Ltd. shareholders' equity:
Common stock, shares issued (in shares)	56,892,114	56,878,489	14,500,000
Common stock, par value (in dollars per share)	$ 0.08	$ 0.08	$ 12.00
Common Class B [Member]
CME Ltd. shareholders' equity:
Common stock, shares issued (in shares)	7,500,936	7,490,936	4,500,000
Common stock, par value (in dollars per share)	$ 0.08	$ 0.08	$ 15.00