Other Assets (Details)	3 Months Ended					0 Months Ended
	Mar. 31, 2013 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2014 Delphis USD ($)	Dec. 31, 2013 Delphis USD ($)	Jun. 28, 2012 Four Seasons USD ($)	Jun. 28, 2012 Four Seasons GBP (£)	Mar. 31, 2014 HCP Ventures IV, LLC USD ($)	Dec. 31, 2013 HCP Ventures IV, LLC USD ($)
Other Assets.
Straight-line rent assets, net of allowance of $34,214 and $34,230 respectively		$ 380,820,000	$ 368,919,000
Allowance on straight-line rent assets		34,214,000	34,230,000
Marketable debt securities, net		245,649,000	244,089,000
Leasing costs, net		104,386,000	104,601,000
Deferred financing costs, net		48,230,000	42,106,000
Goodwill		50,346,000	50,346,000
Other		99,759,000	57,644,000
Total other assets		929,190,000	867,705,000
Other assets
Carrying value of interest accrued related to the Delphis loan				0	0
Reserve related to accrued interest receivable				5,400,000	5,400,000
Loans receivables		371,172,000	366,001,000					12,000,000	10,000,000
Loan receivable, interest rate payable (as a percent)						12.25%	12.25%	12.00%	12.00%
Percentage of counter party's partnership interest in the joint venture, by which loans receivable from unconsolidated joint venture are secured								80.00%
Realized gains on marketable debt securities sold	11,000,000
Marketable debt security, par value							138,500,000
Marketable debt security, par value, discounted						$ 214,900,000	£ 136,800,000
Yield to maturity (as a percent)						12.50%	12.50%