Subsequent Events (Narrative) (Details) (USD $)	12 Months Ended			1 Months Ended	2 Months Ended	12 Months Ended	2 Months Ended
	Dec. 31, 2013 property	Dec. 31, 2012 property	Dec. 23, 2013	Jan. 31, 2014 Subsequent Event [Member] property	Feb. 26, 2014 Subsequent Event [Member] property lease	Dec. 31, 2013 Subsequent Event [Member] property	Feb. 26, 2014 Property Subject To Ground Lease [Member] Subsequent Event [Member] property
Subsequent Event [Line Items]
Ownership percentage in joint ventures	50.00%	75.00%	50.00%	30.00%
Number of real estate properties	2			5		13
Assets	$ 4,223,929,000	$ 4,184,784,000				$ 172,900,000
Debt, net	2,196,539,000					11,100,000
Number of operating properties sold	20			8	2		3
Number of properties held for sale	8	0				8
Proceeds from sale and disposition of property	$ 233,900,000				$ 55,600,000
Number of ground leases					1