Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - $ / shares	9 Months Ended		12 Months Ended
	Sep. 30, 2021		Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value per share	$ 0.01		$ 0.01
Common stock, shares authorized	145,000,000		145,000,000
Common stock, shares issued	115,138,323		114,373,727
Common stock, shares outstanding	115,138,323		114,373,727
Preferred Stock, Par or Stated Value Per Share	$ 0.01		$ 0.01
Preferred Stock, Shares Authorized	20,000,000		20,000,000
Preferred Stock, Dividend Rate, Percentage	8.50%		8.50%
Preferred Stock, Shares Issued	867,846		867,846
Preferred Stock, Shares Outstanding	867,846		867,846
Preferred Stock, Liquidation Preference Per Share	$ 50.00	[1]	$ 50.00
Redeemable stock, shares issued and outstanding	130,242		121,534

[1] The total liquidation preference for the outstanding preferred stock is $43.4 million.