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Long-Term Lease Obligations - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2019 USD ($) property | Dec. 31, 2018 USD ($) property | Dec. 31, 2017 USD ($)
Leases Disclosure [Line Items] |  |  |
Number of properties subject to noncancelable long-term lease | property | 0 | 0 |
Rent expense | $ 806,500 |  |
Rent expense |  | $ 779,800 | $ 774,700
90-year Ground Leasehold Interest |  |  |
Leases Disclosure [Line Items] |  |  |
Ground leasehold interest period | 90 years |  |
Minimum annual lease rent over lease term | $ 1 |  |
99-year Ground Lease |  |  |
Leases Disclosure [Line Items] |  |  |
Ground leasehold interest period | 99 years |  |
Minimum annual lease rent over lease term | $ 1 |  |
Percent of underlying land held under a 99-year ground lease | 3.40% |  |
Flagship Center |  |  |
Leases Disclosure [Line Items] |  |  |
Number of developed parcels | property | 2 |  |

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- Definition Annual Rental Payments Over Lease Term + References No definition available. + Details
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- Definition Lease Expiration Period + References No definition available. + Details
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- Definition Leases Disclosure [Line Items] + References No definition available. + Details
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- Definition Lessee Leasing Arrangements, Number of Properties Under Lease + References No definition available. + Details
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- Definition Number of Developed Parcels + References No definition available. + Details
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- Definition Percentage of Lease Commitment + References No definition available. + Details
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- Definition Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980 + Details
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- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41499-112717 + Details
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- Details
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- Details
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