Corporate Indebtedness (Details 4) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest expense
Interest expense	$ 84,917	$ 83,158	$ 237,847	$ 238,285
Interest income	(776)	(782)	(2,153)	(1,861)
Interest expense, net	84,141	82,376	235,694	236,424
Interest capitalized	$ 7,327	$ 7,972	$ 23,496	$ 18,689