Investment in Real Estate - Additional Information (Details) $ in Thousands, ft² in Millions	3 Months Ended
Mar. 31, 2018 USD ($) ft² Property	Mar. 31, 2017 USD ($)
Real Estate Properties [Line Items]
Number of industrial properties	485
Gross leasable area (GLA) of industrial properties \| ft²	60.1
Impairment of Real Estate \| $	$ 2,756	$ 0
Acquisition Activity
Real Estate Properties [Line Items]
Number of industrial properties	5
Gross leasable area (GLA) of industrial properties \| ft²	0.4
Number of land parcels	1
Held For Sale Activity
Real Estate Properties [Line Items]
Number of industrial properties	19
Gross leasable area (GLA) of industrial properties \| ft²	0.5
Disposition Activity
Real Estate Properties [Line Items]
Number of industrial properties	8
Gross leasable area (GLA) of industrial properties \| ft²	0.5
Number of land parcels	1
Proceeds from sale of industrial properties \| $	$ 42,390
Gain on sale of real estate \| $	$ 20,089
Impairment Activity
Real Estate Properties [Line Items]
Number of industrial properties	1
Number of land parcels	1
Impairment of Real Estate \| $	$ 2,756

Number of Land Parcels

No definition available.

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- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2921-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

The cash inflow from sale of buildings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

+ Details

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Balance Type:	debit
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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.

+ Details

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- Details

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- Details

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- Details

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- Details

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