Annual report pursuant to Section 13 and 15(d)

Related Party Transactions (Details)

v3.10.0.1
Related Party Transactions (Details)
12 Months Ended
Dec. 31, 2018
USD ($)
ft²
property
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Mack [Member]      
Related Party Transaction [Line Items]      
Due from related parties $ 0 $ 0  
Marshall [Member]      
Related Party Transaction [Line Items]      
Due to Related Parties, Current 148,000    
Accounts Payable, Related Parties, Current 0    
RG [Member]      
Related Party Transaction [Line Items]      
Related party revenue $ 1,114,000 1,873,000 $ 2,464,000
Leased Property [Member]      
Related Party Transaction [Line Items]      
Number of real estate properties | property 1    
Lease expiration date September 2019    
Leased Property [Member] | Mack [Member]      
Related Party Transaction [Line Items]      
Area Of Real Estate Property | ft² 7,034    
Lease revenue $ 193,000 $ 187,000 $ 193,000