CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class A Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock (in shares)	522,410	522,410	522,410	522,410
Cash dividends, common stock (in dollars per share)	$ 0.95	$ 0.72	$ 1.63	$ 0.51
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends, common stock (in dollars per share)		$ 0.76	$ 1.72	$ 0.54