Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
PROPERTIES:
Accumulated depreciation on operating properties	$ 385,657	$ 324,543
Development in Process, Accumulated Depreciation	0	0
Real Estate Held for Sale, Accumulated Depreciation	60,078	0
Allowance for doubtful accounts for notes and other receivables	1,736	1,643
Intangible Liabilities, Accumulated Amortization	24,464	16,897
Finite-Lived Intangible Assets, Accumulated Amortization	$ 96,349	$ 76,050
Preferred stock, 20,000,000 shares authorized, $1 par value:
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	20,000,000	20,000,000
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	350,000,000	250,000,000
Common stock, shares issued	220,255,502	220,082,610
Treasury stock, shares	5,584,743	3,570,082