Corporate Indebtedness (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Debt Disclosure [Abstract]
Interest expense	$ 79,163	$ 80,009	$ 157,414	$ 158,758
Interest income	(552)	(458)	(1,084)	(898)
Interest expense, net	78,611	79,551	156,330	157,860
Interest capitalized	$ 6,862	$ 3,301	$ 11,003	$ 6,363