Investments in and Advances to Unconsolidated Joint Ventures - Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Real estate, net	$ 10,209,450	$ 10,731,878
Other assets, net	591,017	578,033
Total assets	12,718,553	14,088,461	$ 15,759,265
Mortgage and other debt	5,477,123
Accounts payable and accrued liabilities	391,583	401,738
Partners' capital	6,512,591	5,594,938	$ 5,941,308	$ 9,746,317
Total liabilities and equity	12,718,553	14,088,461
Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Real estate, net	2,128,147	2,104,090
Other assets, net	479,935	928,790
Total assets	2,608,082	3,032,880
Mortgage and other debt	827,622	900,911
Accounts payable and accrued liabilities	655,177	561,523
Total liabilities and equity	2,608,082	3,032,880
HCP Inc | Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Partners' capital	609,492	915,135
Other partners | Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Partners' capital	$ 515,791	$ 655,311