Common Stock (Details)	9 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 Common Stock	Dec. 31, 2011 Common Stock	Sep. 30, 2012 Common Class A	Sep. 30, 2012 Common Class B	Dec. 31, 2011 Common Class B	Sep. 30, 2012 Common Class C	Dec. 31, 2011 Common Class C	Sep. 30, 2012 Common Class D	Dec. 31, 2011 Common Class D	Sep. 30, 2012 Common Class E	Dec. 31, 2011 Common Class E	Sep. 30, 2012 Common Class F	Dec. 31, 2011 Common Class F	Sep. 30, 2012 Common Class G	Dec. 31, 2011 Common Class G
Common stock rollforward
Shares outstanding at January 1, 2012		1,420,536	1,418,208	66,165	357,882	357,882	209,882	209,882	279,999	279,999	504,276	504,276	1	1	3	3
Restricted stock issuances	6,057			6,057
Stock Repurchased and Retired During Period, Shares				764
Restricted stock used for tax withholding	(764)
Restricted stock forfeitures	(2,965)			(2,965)
Shares outstanding at June 30, 2012		1,420,536	1,418,208	68,493	357,882	357,882	209,882	209,882	279,999	279,999	504,276	504,276	1	1	3	3