Investment Property (Future Minimum Rent) (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Fixed Future Minimum Rentals
April 1, 2018 through December 31, 2018	$ 197,405
2019	252,116
2020	225,353
2021	183,173
2022	157,441
Thereafter	617,924
Total	$ 1,633,412

Future minimum rental payments in aggregate as of the balance sheet date under operating leases.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164653&loc=d3e41551-112718

+ Details

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Period Type:	instant

- References

No definition available.

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- Definition

Future rental payments receivable within the fifth year from the balance sheet date under an operating lease.

+ References

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Namespace Prefix:	us-gaap_
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- Definition

Future rental payments receivable within the fourth year from the balance sheet date under an operating lease.

+ References

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- Definition

Future rental payments receivable within the third year from the balance sheet date under an operating lease.

+ References

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- Definition

Future rental payments receivable within the second year from the balance sheet date under an operating lease.

+ References

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- Definition

Amount of required minimum rental payments receivable in the remainder of the fiscal year following the latest fiscal year ended for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

No definition available.

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- Definition

Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date.

+ References

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