Other Assets (Details)	1 Months Ended	12 Months Ended		12 Months Ended	0 Months Ended
	Jun. 30, 2011 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 HCP Ventures IV, LLC USD ($)	Jun. 28, 2012 Four Seasons USD ($)	Jun. 28, 2012 Four Seasons GBP (£)
Other Assets
Straight-line rent assets, net of allowance of $33,521 and $34,457, respectively		$ 266,620,000	$ 306,294,000
Allowance on straight-line rent assets		34,457,000	33,521,000
Marketable debt securities			222,809,000
Leasing costs, net		92,288,000	93,763,000
Deferred financing costs, net		35,649,000	45,490,000
Goodwill		50,346,000	50,346,000
Marketable equity securities		17,053,000	24,829,000
Other		23,502,000	44,989,000
Total other assets		485,458,000	788,520,000
Other-than-temporary impairment on securities		5,400,000
Cost basis of marketable equity securities		17,100,000	17,100,000
Additions related to accrued interest receivable		5,400,000	5,400,000
Purchase of equity marketable securities	22,400,000
Other assets
Loans receivables		110,253,000	276,030,000	10,000,000
Interest rate on loans receivable from unconsolidated joint venture (as a percent)				12.00%	12.25%	12.25%
Percentage of counter party's partnership interest in the joint venture, by which loans receivable from unconsolidated joint venture are secured				80.00%
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%