Schedule III - Real Estate and Accumulated Depreciation - Schedule of Change in Balance of Accumulated Depreciation (Detail) - USD ($) $ in Thousands  | 
12 Months Ended | |
|---|---|---|
Dec. 31, 2020  | 
Dec. 31, 2019  | 
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| SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward] | ||
| Balance, beginning of period | $ 35,174 | $ 24,051 | 
| Additions during period | 16,655 | 11,230 | 
| Dispositions during period | (2,593) | (107) | 
| Balance, end of period | $ 49,236 | $ 35,174 | 
| X | ||||||||||
- Definition Amount of accumulated depreciation pertaining to real estate investments for entities with a substantial portion of business acquiring and holding investment real estate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
- Definition Amount of decrease to accumulated depreciation for real estate investments sold for entities with a substantial portion of business acquiring and holding investment real estate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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| X | ||||||||||
- Definition Amount of depreciation expense of real estate investments for entities with a substantial portion of business acquiring and holding investment real estate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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