Acquisitions and Dispositions - Additional Information (Detail) $ in Millions	1 Months Ended	6 Months Ended
Jun. 30, 2018 USD ($) Time	Jun. 30, 2019 Acquisition Disposition	Jun. 30, 2018 Time Disposition
Business Acquisitions And Dispositions [Line Items]
Number of acquisitions \| Acquisition		0
Number of dispositions \| Disposition		0	0
Beaumont Medical Sleep Center Building
Business Acquisitions And Dispositions [Line Items]
Total purchase price \| $	$ 4.0
Percentage of building area leased	100.00%
Initial lease terms	9 years 6 months
Number of term renewal options \| Time	2		2
Additional renewal terms	5 years

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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