Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Operating properties, accumulated depreciation	$ 215,856	$ 352,350
Real estate assets and other assets held for sale, accumulated depreciation		7,200
Notes and accounts receivable, allowance for doubtful accounts	1,167	1,353
Intangible assets, accumulated amortization	53,483	103,458
Intangible liabilities, accumulated amortization	$ 12,227	$ 26,890
Preferred stock, par value (in usd per share)	$ 1	$ 1
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	6,867,357	0
Preferred stock, shares outstanding	6,867,357	0
Common stock, par value (in usd per share)	$ 1	$ 1
Common stock, shares authorized	700,000,000	700,000,000
Common stock, shares issued	403,746,938	220,255,676
Treasury stock, shares	10,329,082	8,742,181