Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	11,790,869	10,736,887
Common stock, shares outstanding (in shares)	7,583,466	6,809,280
Treasury stock, shares (in shares)	4,207,403	3,927,607
Series D preferred stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	0	1,150,000
Preferred stock, shares issued (in shares)	0	1,150,000
Preferred stock, shares outstanding (in shares)	0	1,150,000