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Indebtedness (Details) $ in Thousands | 1 Months Ended | 3 Months Ended | 4 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2015 USD ($) property building item | May. 31, 2015 USD ($) property community item | Apr. 30, 2015 USD ($) item | Feb. 28, 2015 USD ($) item | Jan. 31, 2015 USD ($) building | Dec. 31, 2014 USD ($) community | Jun. 30, 2014 | May. 31, 2014 USD ($) | Jun. 30, 2015 USD ($) property building item | Jun. 30, 2014 | Sep. 30, 2014 | Jun. 30, 2015 USD ($) property community building item | Jun. 30, 2014 USD ($) | Dec. 31, 2014 USD ($) | Aug. 05, 2015 USD ($)
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of public issues of unsecured senior notes | item | 6 |  |  |  |  |  |  |  | 6 |  |  | 6 |  |  |
Principal amount of unsecured senior notes | $ 1,744,339 |  |  |  |  | $ 1,743,628 |  |  | $ 1,744,339 |  |  | $ 1,744,339 |  | $ 1,743,628 |
Interest rate (as a percent) | 1.58% |  |  |  |  |  |  |  | 1.58% |  |  | 1.58% |  |  |
Aggregate principal amount of mortgage debt | $ 714,374 |  |  |  |  |  |  |  | $ 714,374 |  |  | $ 714,374 |  |  |
Carrying value of mortgaged properties | 6,325,535 |  |  |  |  | 5,254,761 |  |  | 6,325,535 |  |  | 6,325,535 |  | 5,254,761 |
Assumption of mortgage notes payable |  |  |  |  |  |  |  |  |  |  |  | 169,136 | $ 15,630 |  |
Unsecured revolving credit facility | 615,000 |  |  |  |  | 80,000 |  |  | 615,000 |  |  | 615,000 |  | 80,000 |
Loss on early extinguishment of debt |  |  |  | $ (1,409) |  |  |  |  | (39) |  |  | (1,448) |  |  |
Sale of senior unsecured notes |  |  |  |  |  |  |  |  |  |  |  |  | $ 350,000 |  |
Net proceeds after underwriting discounts from sale of senior unsecured notes |  |  |  |  |  |  |  |  |  |  |  | 644,889 |  |  |
Unsecured revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured revolving credit facility, maximum borrowing capacity | 750,000 |  |  |  |  |  |  |  | 750,000 |  |  | 750,000 |  |  |
Revolving credit facility, available amount | 135,000 |  |  |  |  |  |  |  | $ 135,000 |  |  | 135,000 |  |  | $ 165,000
Extension period of revolving credit facility |  |  |  |  |  |  |  |  | 1 year |  |  |  |  |  |
Principal repayment due until maturity |  |  |  |  |  |  |  |  | $ 0 |  |  |  |  |  |
Option to increase the borrowing capacity under revolving credit facility | $ 1,500,000 |  |  |  |  |  |  |  | $ 1,500,000 |  |  | $ 1,500,000 |  |  |
Interest rate, description |  |  |  |  |  |  |  |  |  |  |  | LIBOR |  |  |
Interest rate added to the base rate (as a percent) |  |  |  |  |  |  |  |  | 1.30% |  |  |  |  |  |
Revolving credit facility, interest rate payable (as a percent) | 1.45% |  |  |  |  |  |  |  | 1.45% |  |  | 1.45% |  |  |
Debt instrument, facility fee (as a percent) |  |  |  |  |  |  |  |  | 0.30% |  |  |  |  |  |
Weighted average interest rate on debt (as a percent) |  |  |  |  |  |  |  |  | 1.47% | 1.42% |  | 1.48% | 1.42% |  |
Unsecured revolving credit facility | $ 615,000 |  |  |  |  |  |  |  | $ 615,000 |  |  | $ 615,000 |  |  | $ 585,000
Senior unsecured notes 4.30% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of unsecured senior notes | $ 250,000 |  |  |  |  |  |  |  | $ 250,000 |  |  | $ 250,000 |  |  |
Interest rate (as a percent) | 4.30% |  |  |  |  |  |  |  | 4.30% |  |  | 4.30% |  |  |
Senior unsecured notes 6.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of unsecured senior notes | $ 200,000 |  |  |  |  |  |  |  | $ 200,000 |  |  | $ 200,000 |  |  |
Interest rate (as a percent) | 6.75% |  |  |  |  |  |  |  | 6.75% |  |  | 6.75% |  |  |
Unsecured senior notes due 2021 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of unsecured senior notes | $ 300,000 |  |  |  |  |  |  |  | $ 300,000 |  |  | $ 300,000 |  |  |
Interest rate (as a percent) | 6.75% |  |  |  |  |  |  |  | 6.75% |  |  | 6.75% |  |  |
Senior unsecured notes 5.625% due in 2042 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of unsecured senior notes | $ 350,000 |  |  |  |  |  |  |  | $ 350,000 |  |  | $ 350,000 |  |  |
Interest rate (as a percent) | 5.625% |  |  |  |  |  |  |  | 5.625% |  |  | 5.625% |  |  |
Mortgages |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount of mortgage debt | $ 714,374 |  |  |  |  |  |  |  | $ 714,374 |  |  | $ 714,374 |  |  |
Number of properties mortgaged | property | 56 |  |  |  |  |  |  |  | 56 |  |  | 56 |  |  |
Number of buildings mortgaged | building | 57 |  |  |  |  |  |  |  | 57 |  |  | 57 |  |  |
Carrying value of mortgaged properties | $ 1,128,624 |  |  |  |  |  |  |  | $ 1,128,624 |  |  | $ 1,128,624 |  |  |
Principal repayment due until maturity | 4,351 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayments mortgage note | $ 4,867 | $ 15,077 | $ 6,274 | $ 29,227 |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate on debt (as a percent) | 5.65% |  |  |  |  |  |  |  | 5.65% |  |  | 5.65% |  |  |
Weighted average interest rate on debt (as a percent) |  |  |  | 6.02% |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate on prepaid debt (as a percent) | 5.81% | 5.70% | 5.81% |  |  |  |  |  |  |  |  |  |  |  |
Number of mortgage notes | item |  | 4 | 1 | 1 |  |  |  |  |  |  |  |  |  |  |
Number of properties encumbered under mortgage notes | property | 1 | 4 |  |  |  |  |  |  | 1 |  |  | 1 |  |  |
Capital leases |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Carrying value of mortgaged properties | $ 35,239 |  |  |  |  |  |  |  | $ 35,239 |  |  | $ 35,239 |  |  |
Number of properties recorded under capital lease | property | 2 |  |  |  |  |  |  |  | 2 |  |  | 2 |  |  |
Capital leases | $ 12,468 |  |  |  |  |  |  |  | $ 12,468 |  |  | $ 12,468 |  |  |
Senior unsecured notes due 2019 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of unsecured senior notes | $ 400,000 |  |  |  |  |  |  |  | $ 400,000 |  |  | $ 400,000 |  |  |
Interest rate (as a percent) | 3.25% |  |  |  |  |  |  |  | 3.25% |  |  | 3.25% |  |  |
Senior unsecured notes due 2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Principal amount of unsecured senior notes | $ 250,000 |  |  |  |  |  |  |  | $ 250,000 |  |  | $ 250,000 |  |  |
Interest rate (as a percent) | 4.75% |  |  |  |  |  |  |  | 4.75% |  |  | 4.75% |  |  |
Unsecured Debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured term loan facility | $ 350,000 |  |  |  |  | 350,000 |  | $ 350,000 | $ 350,000 |  |  | $ 350,000 |  | $ 350,000 |
Interest rate, description |  |  |  |  |  |  |  | LIBOR |  |  | LIBOR |  |  |  |
Interest rate added to the base rate (as a percent) |  |  |  |  |  |  |  | 1.40% |  |  |  |  |  | 1.40% |
Weighted average interest rate on debt (as a percent) |  |  |  |  |  |  | 1.55% |  | 1.60% |  |  | 1.60% |  |  |
Maximum borrowing capacity that may be increased |  |  |  |  |  | 700,000 |  |  |  |  |  |  |  | $ 700,000 |
Senior living communities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of communities | community |  |  |  |  |  |  |  |  |  |  |  | 19 |  |  |
Senior living communities | Agreement to acquire |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Assumption of mortgage notes payable |  | $ 139,181 |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate on debt (as a percent) |  | 4.43% |  |  |  |  |  |  |  |  |  |  |  |  |
Bridge loan commitment received |  |  |  |  |  | $ 700,000 |  |  |  |  |  |  |  | $ 700,000 |
Number of communities | community |  | 37 |  |  |  | 38 |  |  |  |  |  |  |  |  |
MOBs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of properties acquired with assumed mortgage debt | building |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |
MOBs | Mortgages | Significant Unobservable Inputs (Level 3) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Indebtedness |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Assumption of mortgage notes payable |  |  |  |  | $ 29,955 |  |  |  |  |  |  |  |  |  |
Fair value of mortgage notes payable |  |  |  |  | $ 31,029 |  |  |  |  |  |  |  |  |  |
Weighted average interest rate on debt (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 4.73% |  |  |

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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://www.xbrl.org/2003/role/presentationRef -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=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -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=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
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