Investments in Unconsolidated Entities (Summary of Investments in Unconsolidated Entities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 482,914	$ 445,585
Seniors Housing Operating
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 344,982	$ 352,430
Seniors Housing Operating \| Minimum
Schedule of Equity Method Investments [Line Items]
Percentage Ownership	10.00%	10.00%
Seniors Housing Operating \| Maximum
Schedule of Equity Method Investments [Line Items]
Percentage Ownership	50.00%	50.00%
Triple-net
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 34,284	$ 22,856
Triple-net \| Minimum
Schedule of Equity Method Investments [Line Items]
Percentage Ownership	10.00%	10.00%
Triple-net \| Maximum
Schedule of Equity Method Investments [Line Items]
Percentage Ownership	49.00%	49.00%
Outpatient Medical
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 103,648	$ 70,299
Outpatient Medical \| Minimum
Schedule of Equity Method Investments [Line Items]
Percentage Ownership	43.00%	43.00%
Outpatient Medical \| Maximum
Schedule of Equity Method Investments [Line Items]
Percentage Ownership	50.00%	50.00%

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

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- 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

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- 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.

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