Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accumulated depreciation on operating properties	$ 181,928	$ 215,856
Real estate assets and other assets held for sale, accumulated depreciation	73,525
Allowance for doubtful accounts for notes and accounts receivables	1,410	1,167
Accumulated amortization on intangible assets	70,588	53,483
Accumulated amortization on intangible liabilities	$ 16,904	$ 12,227
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	6,867,357
Preferred stock, shares outstanding	6,867,357	6,867,357
Common stock, par value (in usd per share)	$ 1	$ 1
Common stock, shares authorized	700,000,000	700,000,000
Common stock, shares issued	429,225,700	403,746,938
Treasury stock, shares	10,329,082	10,329,082