v3.7.0.1
Mortgages and Notes Payable - Summary of Mortgages and Notes Payable (Parenthetical) (Detail)
6 Months Ended
Jun. 30, 2017
Minimum  
Line Of Credit Facility [Line Items]  
Term of note 59 months
Maximum  
Line Of Credit Facility [Line Items]  
Term of note 239 months
M&T Bank | 1 Month LIBOR | New York State Energy Research and Development Authority Program  
Line Of Credit Facility [Line Items]  
Blended interest rate 1.64%