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Indebtedness - Narrative (Details) | 1 Months Ended | 5 Months Ended | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Feb. 25, 2021 USD ($) | Jan. 31, 2021 USD ($) | Jun. 30, 2020 USD ($) | May 31, 2020 USD ($) property | Apr. 30, 2020 USD ($) | Feb. 29, 2020 USD ($) property | May 31, 2019 USD ($) community | Jun. 30, 2018 USD ($) property | Mar. 31, 2018 USD ($) property | Feb. 28, 2018 USD ($) property | Jun. 02, 2020 | Dec. 31, 2020 USD ($) property | Dec. 31, 2019 USD ($) property | Dec. 31, 2018 USD ($) | Feb. 22, 2021 USD ($) | Jan. 30, 2021 USD ($) | Sep. 30, 2018 USD ($) property | Jul. 31, 2018 USD ($) property | Jan. 31, 2018 USD ($) property
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured revolving credit facility |  |  |  |  |  |  |  |  |  |  |  | $ 0 | $ 537,500,000 |  |  |  |  |  |
Revolving credit facility, available amount |  |  |  |  |  |  |  |  |  |  |  | $ 1,000,000,000 |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  | 397 |  |  |  |  |  |  |
Total real estate properties, gross |  |  |  |  |  |  |  |  |  |  |  | $ 7,410,730,000 | 7,461,586,000 |  |  |  |  |  |
Mortgage debt assumed |  |  |  |  |  |  |  |  |  |  |  | 0 | 0 | $ 44,386,000 |  |  |  |  |
Loss on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  | 427,000 | 44,000 | $ 22,000 |  |  |  |  |
Senior unsecured notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt |  |  |  |  |  |  |  |  |  |  |  | $ 2,650,000,000 | $ 1,850,000,000 |  |  |  |  |  |
Senior Living Communities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  | 28 | 25 |  |  |  |  |  |
Medical Office |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  | 7 | 20 |  |  |  |  |  |
Life Science |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |
Unsecured Revolving Credit Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured revolving credit facility, maximum borrowing capacity |  |  |  |  |  |  |  |  |  |  |  | $ 800,000,000 |  |  |  |  |  |  |
Revolving credit facility, interest rate payable (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 2.60% |  |  |  |  |  |  |
Loan commitment fee percentage |  |  |  |  |  |  |  |  |  |  |  | 0.30% |  |  |  |  |  |  |
Weighted average annual interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  | 2.90% |  |  |  |  |  |
Unsecured revolving credit facility |  |  |  |  |  |  |  |  |  |  |  | $ 0 |  |  |  |  |  |  |
Weighted average interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 2.20% | 3.40% | 3.00% |  |  |  |  |
Unsecured Revolving Credit Facility | Medical Office and Life Science |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  | 91 |  |  |  |  |  |  |
Total real estate properties, gross |  |  |  |  |  |  |  |  |  |  |  | $ 1,429,612,000 |  |  |  |  |  |  |
Senior unsecured notes due 2019 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  | 325.00% |  |  |  |  |  |  |  |  |  |  |  |
Loss on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  |  | $ 17,000 |  |  |  |  |  |
Debt extinguishment, amount |  |  |  |  |  |  | $ 400,000 |  |  |  |  |  |  |  |  |  |  |  |
Debt extinguishment, accrued and interest payable |  |  |  |  |  |  | 6,500,000 |  |  |  |  |  |  |  |  |  |  |  |
Senior Unsecured Note Due July 2019 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt |  |  |  |  |  |  | $ 42,211,000 |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  | 3.79% |  |  |  |  |  |  |  |  |  |  |  |
Number of communities | community |  |  |  |  |  |  | 4 |  |  |  |  |  |  |  |  |  |  |  |
Unsecured Notes Due June 2023 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  | 6.64% |  |  |  |  |  |  |  |  |
Mortgage debt assumed |  |  |  |  |  |  |  |  |  | $ 16,748,000 |  |  |  |  |  |  |  |  |
Unsecured Notes Due June 2023 | Senior Living Communities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |
Unsecured Notes Due July 2043 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  | 4.44% |  |  |  |  |  |  |  |  |  |
Mortgage debt assumed |  |  |  |  |  |  |  |  | $ 11,050,000 |  |  |  |  |  |  |  |  |  |
Unsecured Notes Due July 2043 | Medical Office |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |
Senior Notes Due October 2022 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  | 5.75% |  |  |  |  |  |  |  |  |  |  |
Mortgage debt assumed |  |  |  |  |  |  |  | $ 16,588,000 |  |  |  |  |  |  |  |  |  |  |
Senior Notes Due October 2022 | Senior Living Communities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |
Term loan due 2020 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average annual interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  | 2.40% |  |  |  |  |  |  |  |
Principal amount of debt |  |  | $ 250,000 |  |  |  |  |  |  |  |  |  | 250,000,000 |  |  |  |  |  |
Loss on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  | 26,000 | (27,000) |  |  |  |  |  |
Unsecured term loan due January 2020 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt |  |  |  |  |  |  |  |  |  |  |  |  | $ 350,000,000 |  |  |  |  |  |
Term loan due 2022 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt |  |  |  |  |  |  |  |  |  |  |  | $ 200,000,000 |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 2.80% |  |  |  |  |  |  |
Weighted average interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 2.70% | 3.70% | 3.40% |  |  |  |  |
Mortgage maturing in September 2043 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.40%
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1
Secured debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4,338,000
Senior Unsecured Notes Due October 2018 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 90,602,000 |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 12 |
Weighted average interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5.00% |
Senior Unsecured Notes Due January 2019 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 6,325,000 |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.70% |  |
Number of properties owned (property) | property |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |
Loss on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 22,000 |  |  |  |  |
Senior Unsecured Notes Due March 2026 | Life Science |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  | 6.25% |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  | $ 246,000 |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  | $ 1,554,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Senior unsecured note due 2020 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  | 6.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt extinguishment, amount |  |  |  |  | $ 200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Accrued and unpaid interest |  |  |  |  | $ 6,750,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mortgage notes 7.49% maturing in January 2022 | Medical Office |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  | 7.49% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties owned (property) | property |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on early extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  | $ 155,000 |  |  |  |  |  |  |
Repayments of debt |  |  |  | $ 1,213,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Unsecured Note Due March 2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt |  |  | $ 1,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  | 9.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds from offering |  |  | $ 982,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, redemption percentage, maximum |  |  | 40.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, outstanding percentage, maximum |  |  | 50.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Unsecured Revolving Credit Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured revolving credit facility, maximum borrowing capacity |  | $ 800,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,000,000,000 |  |  |
Unsecured revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 |  |  |  |
Revolving credit facility, available amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 800,000,000 |  |  |  |
Capital expenditure funding capacity |  | 250,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum liquidity requirement amount |  | $ 200,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Senior Unsecured Notes Due June 2021 | Senior unsecured notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt | $ 200,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) | 6.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Senior Unsecured Note Due 2031 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) | 4.375% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Senior Unsecured Notes Due 2031 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt | $ 500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Senior Unsecured Notes Due 2031 | Senior unsecured notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of debt | $ 500,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) | 4.375% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net proceeds from offering | $ 491,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Revolving Credit Facility | Unsecured Revolving Credit Facility | LIBOR |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis points per annum (as a percent) |  | 0.30% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event | Forecast | Unsecured Revolving Credit Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Capital expenditure funding capacity | $ 350,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
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- Definition Gross amount of debt extinguished. + References No definition available. + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
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- Definition The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used. + References No definition available. + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition The amount of debt that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4313-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586 + Details
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- Definition The number of real estate properties owned as of the balance sheet date. + References No definition available. + Details
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- Definition The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585 + Details
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