Equity - Additional Information (Details)	1 Months Ended	9 Months Ended		12 Months Ended
	May 31, 2021 $ / shares shares	Sep. 30, 2021 USD ($) property $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Feb. 28, 2021 USD ($)	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
Redemption of OP units (in units)		1,598,906
Partners' capital account (in units)		824,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Properties Disposed by LCIF
Equity [Line Items]
Number of properties sold | property		3
LCIF
Equity [Line Items]
Redemption of OP units (in units)		1,598,906
LCIF | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Properties Disposed by LCIF
Equity [Line Items]
Number of properties sold | property		3
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
Forward Contracts
Equity [Line Items]
Number of shares sold (in shares)		3,875,751
Proceeds from sale of stock | $		$ 41,933,000	$ 0
Share-based Payment Arrangement
Equity [Line Items]
Shares granted (in shares)		38,803	35,880
Grant date fair value | $		$ 437,000	$ 375,000
At-The-Market Program
Equity [Line Items]
Number of shares sold (in shares)		1,052,800	5,950,882
Proceeds from sale of stock | $		$ 13,574,000	$ 61,032,000
Sale of stock, authorized amount (up to) | $					$ 350,000,000
Common shares amount available for issuance | $		$ 294,985,000
At-The-Market Program | Forward Contracts
Equity [Line Items]
Number of shares to be settled on a forward basis (in shares)		4,763,989	0
Shares to be settled on forward basis, aggregate value | $		$ 50,721,000
Underwritten Offering
Equity [Line Items]
Number of shares sold (in shares)				17,250,000
Proceeds from sale of stock | $				$ 164,000,000
Sale of stock (in dollars per share) | $ / shares				$ 9.60
Underwritten Offering | Forward Contracts
Equity [Line Items]
Number of shares to be settled on a forward basis (in shares)	16,000,000
Shares to be settled on forward basis, aggregate value | $		$ 189,777,000
Sale of stock (in dollars per share) | $ / shares	$ 12.11