Unaudited Condensed Consolidated Balance Sheets (Parenthetical)	Sep. 30, 2019 $ / shares shares	Dec. 31, 2018 $ / shares shares
Class A Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 1	$ 1
Common stock, shares outstanding (in shares) | shares	5,425,640	5,352,590
Class B Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 1	$ 1
Common stock, convertible conversion ratio	1	1
Common stock, shares outstanding (in shares) | shares	1,568,680	1,568,810