Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000.0	100,000,000.0
Common stock, shares outstanding	62,300,000	62,400,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000.0	10,000,000.0
Preferred stock, shares outstanding	0	0