XML 67 R53.htm IDEA: XBRL DOCUMENT v3.10.0.1
Long Term Lease Obligations - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2018
USD ($)
property
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Leases Disclosure [Line Items]      
Number of properties subject to noncancelable long-term lease | property 0    
Minimum rental obligations   $ 10,500 $ 159,000
Rent expense $ 779,800 $ 774,700 $ 843,300
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