CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Tenant and other receivables, allowance for doubtful accounts	$ 950,000	$ 1,492,000
Intangible assets, accumulated amortization	$ 21,598,000	$ 19,187,000
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, authorized (in shares)	25,000,000.0
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	80,200,000	79,537,000
Common stock, shares outstanding (in shares)	80,200,000	79,537,000
Series B Preferred Stock
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	3,450,000	3,450,000
Preferred shares, outstanding (in shares)	3,450,000	3,450,000
Liquidation preference	$ 95,791,000	$ 89,430,000
Series C Preferred Stock
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	6,900,000	6,900,000
Preferred shares, outstanding (in shares)	6,900,000	6,900,000
Liquidation preference	$ 191,130,000	$ 178,710,000
Series D Preferred Stock
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	5,000,000	5,000,000
Preferred shares, outstanding (in shares)	5,000,000	5,000,000
Liquidation preference	$ 137,891,000	$ 129,297,000