Corporate Indebtedness (Schedule of Consolidated Interest Expense, Excluding Capitalized Interest)(Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest expense
Interest expense before capitalized interest	$ 78,715	$ 92,244	$ 276,437	$ 261,343
Interest capitalized	(6,084)	(7,327)	(18,135)	(23,496)
Interest income	(66)	(776)	(1,976)	(2,153)
Interest expense, net	$ 72,565	$ 84,141	$ 256,326	$ 235,694