Common Stock (Details)	3 Months Ended			3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Common Stock	Dec. 31, 2012 Common Stock	Mar. 31, 2013 Common Class A	Mar. 31, 2013 Common Class B	Dec. 31, 2012 Common Class B	Mar. 31, 2013 Common Class C	Dec. 31, 2012 Common Class C	Mar. 31, 2013 Common Class D	Dec. 31, 2012 Common Class D	Mar. 31, 2013 Common Class E	Dec. 31, 2012 Common Class E	Mar. 31, 2013 Common Class F	Dec. 31, 2012 Common Class F	Mar. 31, 2013 Common Class G	Dec. 31, 2012 Common Class G
Common stock rollforward
Shares outstanding at January 1, 2012		1,425,160	1,420,034.000	67,991	357,882	357,882	209,882	209,882	279,999	279,999	504,276	504,276	1	1	3	3
Restricted stock issuances	6,042.000			6,042
Restricted stock used for tax withholding	(123.000)			(123)
Restricted stock forfeitures	(793.000)			(793)
Shares outstanding at June 30, 2012		1,425,160	1,420,034.000	73,117	357,882	357,882	209,882	209,882	279,999	279,999	504,276	504,276	1	1	3	3