Equity - Activity for Class B Common Stock and Treasury Stock (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Class B Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of Treasury Stock			200,000
Common Stock | Class B Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	101,211,023	100,763,162	100,803,382	101,100,453
Stock Award Activity	7,500	5,000	528,574	501,219
Purchase of Treasury Stock	79,592	276,982	193,025	1,110,492
Ending Balance	101,138,931	100,491,180	101,138,931	100,491,180
Treasury Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(8,294,433)	(8,742,294)	(8,702,074)	(8,405,003)
Stock Award Activity	7,500	5,000	528,574	501,219
Purchase of Treasury Stock	79,592	276,982	193,025	1,110,492
Ending Balance	(8,366,525)	(9,014,276)	(8,366,525)	(9,014,276)