Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Real estate assets, accumulated depreciation	$ 803,073	$ 577,139
Real estate assets held for sale, accumulated depreciation	14,188	61,093
Intangible liabilities, accumulated amortization	73,967	55,798
Liabilities of real estate assets held for sale, accumulated amortization	$ 1,205	$ 7,771
Preferred stock, par value (in usd per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	1,716,837
Preferred stock, shares outstanding (in shares)	0	1,716,837
Common stock, par value (in usd per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	151,149,289	149,347,382
Common stock, shares outstanding (in shares)	151,149,289	149,347,382
Treasury stock, shares (in shares)	2,584,933	2,584,933