CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Intangible assets, accumulated amortization	$ 21,900,000	$ 21,598,000
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)	80,617,000	80,200,000
Common stock, shares outstanding (in shares)	80,617,000	80,200,000
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	$ 97,381,000	$ 95,791,000
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	$ 194,235,000	$ 191,130,000
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	$ 140,040,000	$ 137,891,000