Subsequent Events (Narrative) (Details) (USD $)	6 Months Ended		1 Months Ended		1 Months Ended	6 Months Ended	1 Months Ended
	Jun. 30, 2014 property	Dec. 31, 2013	Aug. 07, 2014 Subsequent Event [Member] lease	Jun. 30, 2014 Property Subject to Ground Lease [Member]	Aug. 07, 2014 Property Subject to Ground Lease [Member] Subsequent Event [Member] property	Jun. 30, 2014 8.1% Senior Unsecured Notes [Member]	Aug. 07, 2014 8.1% Senior Unsecured Notes [Member] Subsequent Event [Member]
Subsequent Event [Line Items]
Number of ground leases			1
Number of operating properties sold	5				3
Total assets	$ 3,863,401,000	$ 4,223,929,000		$ 11,000,000
Debt stated interest rate						8.10%	8.10%
Debt maturity date						Sep. 15, 2019	Sep. 15, 2019
Senior unsecured notes						$ 90,000,000	$ 90,000,000
Debt redemption date						Sep. 15, 2014	Sep. 15, 2014
Debt redemption price, percentage							100.00%