Investments in Unconsolidated Entities (Summary of Investments in Unconsolidated Entities) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 450,027	$ 445,585
Triple Net
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 22,002	$ 22,856
Triple Net \| Minimum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	10.00%	10.00%
Triple Net \| Maximum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	49.00%	49.00%
Seniors Housing Facilities Operating [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 339,737	$ 352,430
Seniors Housing Facilities Operating [Member] \| Minimum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	10.00%	10.00%
Seniors Housing Facilities Operating [Member] \| Maximum
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	50.00%	50.00%
Outpatient Medical
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	43.00%	43.00%
Investments in unconsolidated entities	$ 88,288	$ 70,299

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The book value of investments in real estate joint ventures including direct and indirect investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(d))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_RealEstateInvestmentsJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=well_TripleNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=well_SeniorsHousingFacilitiesOperatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=well_OutpatientMedicalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: