Subsequent Events (Details) (USD $)	9 Months Ended					0 Months Ended
	Sep. 30, 2012	Sep. 30, 2013 Class A Common Stock	Dec. 31, 2012 Class A Common Stock	Sep. 30, 2013 Class B Non-Voting Common Stock	Dec. 31, 2012 Class B Non-Voting Common Stock	Oct. 15, 2013 Subsequent Event	Nov. 07, 2013 Subsequent Event Dividend declared	Oct. 15, 2013 Subsequent Event Class A Common Stock	Oct. 15, 2013 Subsequent Event Class B Non-Voting Common Stock
Subsequent Events
Common stock issued (in shares)								1,829,339
Commission or other remuneration paid						$ 0
Cash consideration of issuance of common stock	$ 43,000							$ 0
Increase in outstanding common stock (in shares)								1,829,339
Common stock, shares issued		99,924,963	99,417,998	1,829,339	1,829,339				0
Common stock, shares outstanding		99,924,963	99,417,998	1,829,339	1,829,339				0
Quarterly cash dividends on common stock							$ 0.03