Other Assets (Details) $ in Thousands	1 Months Ended
	Jun. 30, 2015 USD ($) item	Jun. 30, 2012 GBP (£)	Dec. 31, 2014 USD ($)
Other assets
Straight-line rent receivables, net of allowance of $34,168 and $34,182, respectively	$ 368,435		$ 355,864
Allowance on straight-line rent assets	34,168		34,182
Marketable debt securities	191,846		231,442
Leasing costs, net	158,522		146,500
Deferred financing costs, net	56,743		47,592
Goodwill	50,346		50,346
Other	134,315		108,428
Total other assets	960,207		940,172
Loans receivables	862,621		906,961
Four Seasons Health Care Ltd [Member]
Other assets
Total amount outstanding | £		£ 175,000,000
Brookdale Senior Living
Other assets
Loans receivables	$ 19,000		26,000
Number of installments | item	8
Four Seasons
Other assets
Investment Interest Rate	12.25%
Marketable debt security, par value | £		138,500,000
Purchase of debt securities | £		£ 136,800,000
Portion of debt held, as a percent.		79.00%
HCP Ventures IV
Other assets
Loans receivables	$ 19,000		$ 15,000
Loan receivable, interest rate payable (as a percent)	12.00%