CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Allowance for credit losses	$ 1,099	$ 339
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000	50,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Treasury stock (in shares)		163
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	600,000	600,000
Common stock, shares issued	28,943	30,928
Common stock, shares outstanding	28,943	30,765
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.00	$ 0.00
Common stock, shares authorized	180,000	180,000
Common stock, shares issued	15,685	15,939
Common stock, shares outstanding	15,685	15,939