Equity - Additional Information (Details)	3 Months Ended
	Mar. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2018 shares	Jul. 31, 2015 shares
Equity [Line Items]
Authorized amount (in shares)				10,000,000	10,000,000
Treasury stock acquired (in shares)	0	1,329,940
Treasury stock acquired, average cost (in dollars per share) | $ / shares		$ 8.28
Shares remaining available for repurchase (in shares)	8,976,315
Series C cumulative convertible preferred, shares outstanding (in shares)	1,935,400		1,935,400
Series C cumulative convertible preferred, liquidation preference | $	$ 96,770,000		$ 96,770,000
OP unit equivalent in common shares	1.13
Partners' capital account (in units)	2,485,000
Series C Cumulative Convertible Preferred Stock
Equity [Line Items]
Series C cumulative convertible preferred, shares outstanding (in shares)	1,935,400
Preferred stock, dividend per annum (in dollars per share) | $ / shares	$ 3.25
Series C cumulative convertible preferred, liquidation preference | $	$ 96,770,000
Convertible preferred stock, conversion ratio	2.4339
Preferred stock conversion, threshold conversion price percentage (at least)	1.25
Share-based Payment Arrangement
Equity [Line Items]
Shares granted (in shares)	11,850	11,675
Grant date fair value | $	$ 125,000	$ 125,000
At-The-Market Program
Equity [Line Items]
Number of shares sold		1,559,714
Proceeds from sale of stock | $		$ 17,266,000
Sale of stock, authorized amount (up to) | $	350,000,000
Common shares amount available for issuance | $	$ 309,048,000
At-The-Market Program | Forward Contracts
Equity [Line Items]
Number of shares to be settled on a forward basis (in shares)	3,649,023
Number of shares sold	8,639,740
Proceeds from sale of stock | $	$ 94,493,000