Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Common stock, par value (in $ 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)	10,715,805	10,552,624
Common stock, shares outstanding (in shares)	6,944,892	6,997,382
Treasury stock, shares (in shares)	3,770,913	3,555,242
Series D convertible preferred stock
Preferred stock, par value (in $ per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,150,000	1,150,000
Preferred stock, shares issued (in shares)	1,150,000	1,150,000
Preferred stock, shares outstanding (in shares)	1,150,000	1,150,000