Fair Value Measurements (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Carrying value, mortgage and notes payable	$ 3,960,285	$ 4,737,459
Carrying value, margins payable	0	59,681
Estimated fair value, mortgage and notes payable	3,967,792	4,748,276
Carrying Value Of Line Of Credit	200,000	200,180
Estimated Fair Value of Line of Credit	200,000	200,180
Estimated fair value, margins payable	$ 0	$ 59,681