Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2017	Mar. 02, 2018
Property, Plant and Equipment [Line Items]
Ground lease commitments, 2018	$ 2,694,000
Ground lease commitments, 2019	2,730,000
Ground lease commitments, 2020	2,014,000
Ground lease commitments, 2021	1,299,000
Ground lease commitments, 2022	1,338,000
Ground lease commitments, Thereafter	12,829,000
701 Seventh WRT Investor LLC [Member]
Property, Plant and Equipment [Line Items]
Future funding commitments	2,920,000
701 Seventh WRT Investor LLC [Member] \| Subsequent Event [Member]
Property, Plant and Equipment [Line Items]
Future funding commitments		$ 1,667,000
New York, NY [Member] \| Ground Lease [Member]
Property, Plant and Equipment [Line Items]
Ground lease commitments, 2018	1,791,000
Ground lease commitments, 2019	1,844,000
Ground lease commitments, 2020	1,900,000
Ground lease commitments, 2021	1,957,000
Ground lease commitments, 2022	2,015,000
Ground lease commitments, Thereafter	$ 99,912,000
Expiration date	Jun. 01, 2053
Chicago, IL [Member] \| Ground Lease [Member]
Property, Plant and Equipment [Line Items]
Ground lease commitments, 2018	$ 440,000
Ground lease commitments, 2019	440,000
Ground lease commitments, 2020	440,000
Ground lease commitments, 2021	440,000
Ground lease commitments, 2022	440,000
Ground lease commitments, Thereafter	$ 5,167,000
Expiration date	Sep. 19, 2034

Future funding commitments.

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- Definition

Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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- Definition

Future rental payments receivable within one year of the balance sheet date under an operating lease.

+ References

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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- Definition

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

+ References

+ Details

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- Definition

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

+ References

+ Details

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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

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

+ References

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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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