Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Undesignated preferred stock, par value	$ 0.01	$ 0.01
Undesignated preferred stock, shares authorized	10,000,000	10,000,000
Undesignated preferred stock, shares issued	0	0
Undesignated preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	250,245,831	242,117,089
Common stock, shares outstanding	250,245,831	242,117,089