Quarterly report pursuant to Section 13 or 15(d)

Real Estate and Intangible Assets - Additional Information (Detail)

v3.10.0.1
Real Estate and Intangible Assets - Additional Information (Detail)
$ in Thousands
3 Months Ended 6 Months Ended
May 26, 2016
USD ($)
ft²
Jun. 30, 2018
USD ($)
ft²
property
Jun. 30, 2017
USD ($)
ft²
property
Jun. 30, 2018
USD ($)
ft²
property
Jun. 30, 2017
USD ($)
ft²
property
Jun. 22, 2018
Jun. 22, 2017
Real Estate Properties [Line Items]              
Number of properties acquired | property   1 1 1 1    
Purchase Price       $ 14,341      
Change in unrealized gain related to interest rate hedging instruments, net   $ 289 $ 179 $ 783 $ 179    
Number of leased properties | property       1 1    
Total amortization expense related to lease intangible assets   4,300 3,500 $ 8,600 $ 7,000    
Amortization related to below-market lease   500 300 1,000 700    
Above market leases              
Real Estate Properties [Line Items]              
Amortization related to above-market lease   200 100 500 300    
Building and Tenant Improvements              
Real Estate Properties [Line Items]              
Real estate depreciation expense   $ 7,500 $ 6,400 $ 14,800 $ 12,800    
Series of Property Acquisitions              
Real Estate Properties [Line Items]              
Aggregate Square Footage Sold | ft²   127,444 60,016 127,444 60,016    
Purchase Price       $ 14,341 $ 15,697    
Mortgage loans on real estate, new mortgage loans       $ 0 $ 11,179    
Lease Term       9 years 9 months 18 days 8 years 6 months    
Annualized GAAP Rent       $ 1,087 $ 1,680    
Acquisition Expenses       91 247    
Conshohocken, Pennsylvania              
Real Estate Properties [Line Items]              
Aggregate Square Footage Sold | ft² 60,016            
Purchase Price $ 15,700            
Mortgage loans on real estate, new mortgage loans $ 11,200            
Lease Term 8 years 6 months            
Annualized GAAP Rent $ 1,700            
Stated interest rate (as percent)           1.80% 1.80%
Asset Acquisitions              
Real Estate Properties [Line Items]              
Purchase Price         15,697    
Interest rate swap              
Real Estate Properties [Line Items]              
Change in unrealized gain related to interest rate hedging instruments, net   $ 192 $ 179 313 179    
Interest rate swap | Asset Acquisitions              
Real Estate Properties [Line Items]              
Liabilities Assumed       0 $ 42    
Change in unrealized gain related to interest rate hedging instruments, net       $ 700      
LIBOR | Interest rate swap | Conshohocken, Pennsylvania              
Real Estate Properties [Line Items]              
Derivative rate (as a percent)             3.55%