Credit Losses, Financial Assets and Other Instruments (Credit Risk Classification) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Investing Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	$ 67,112
2017	1,019
2018	0
2019	6,040
2020	1,028
2021	6
Total	75,205	$ 71,605
Investing Receivables \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	67,112
2017	1,019
2018	0
2019	0
2020	1,028
2021	6
Total	69,165
Investing Receivables \| Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	0
2017	0
2018	0
2019	6,040
2020	0
2021	0
Total	6,040
Tenant Notes Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	234
2017	0
2018	1,114
2019	231
2020	2,111
2021	0
Total	3,690
Tenant Notes Receivables \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	0
2017	0
2018	965
2019	74
2020	308
2021	0
Total	1,347
Tenant Notes Receivables \| Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	234
2017	0
2018	149
2019	157
2020	1,803
2021	0
Total	2,343
Sales-Type Lease Receivables \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	0
2017	0
2018	0
2019	0
2020	6,405
2021	0
Total	$ 6,405

Amount of financing receivable originated more than five years prior to current fiscal year.

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Amount of financing receivable originated four years prior to current fiscal year.

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Amount of financing receivable originated in current fiscal year.

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Amount of financing receivable originated three years prior to current fiscal year.

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