Corporate Indebtedness (Schedule of Consolidated Interest Expense, Excluding Capitalized Interest)(Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Interest expense
Interest expense	$ 95,568	$ 84,083	$ 197,722	$ 169,099
Interest capitalized	(5,433)	(7,611)	(12,051)	(16,169)
Interest income	(1,046)	(726)	(1,910)	(1,377)
Interest expense, net	$ 89,089	$ 75,746	$ 183,761	$ 151,553