CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Preferred stock, authorized (in shares)	30,000,000
Preferred stock, outstanding (in shares)	6,799,467	6,799,467
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	250,000,000	250,000,000
Common stock, issued (in shares)	103,900,452	89,614,601
Common stock, outstanding (in shares)	103,900,452	89,614,601
7.25% Series A cumulative redeemable preferred stock, $0.01 par value, liquidation preference $25.00 per share, 9,959,650 shares authorized, 6,799,467 shares issued and outstanding as of September 30, 2021 and December 31, 2020
Preferred stock, dividend rate	7.25%	7.25%
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (in dollars per share)	$ 25.00	$ 25.00
Preferred stock, authorized (in shares)	9,959,650	9,959,650
Preferred stock, issued (in shares)	6,799,467	6,799,467
Preferred stock, outstanding (in shares)	6,799,467	6,799,467
6.875% Series B cumulative redeemable perpetual preferred stock, $0.01 par value, liquidation preference $25.00 per share, 11,450,000 shares authorized, 4,503,893 and 3,861,953 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively
Preferred stock, dividend rate	6.875%	6.875%
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (in dollars per share)	$ 25.00	$ 25.00
Preferred stock, authorized (in shares)	11,450,000	11,450,000
Preferred stock, issued (in shares)	4,503,893	3,861,953
Preferred stock, outstanding (in shares)	4,503,893	3,861,953