Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	12,000	12,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	33,064,923	33,004,717
Common stock, shares outstanding	20,128,813	20,098,607
Class B [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	1,680,590	1,680,590
Common stock, shares outstanding	1,680,590	1,680,590