Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Allowance for doubtful accounts receivable	$ 1,116	$ 671
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	125,000,000
Series A
Common stock, shares, issued	20,855,200	20,854,975
Series B
Common stock, shares, issued	2,469,083	2,469,308
Treasury Stock | Series A
Treasury stock Series A, shares held	1,913,860	1,913,860