Annual report pursuant to Section 13 and 15(d)

Management Agreement (Details)

v3.8.0.1
Management Agreement (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Management Agreement [Line Items]      
Percentage of independent directors to reach majority 0.6667%    
Number of days prior written noticed needed to terminate agreement 30 days    
Termination payment percentage equal to last 4 quarters 300.00%    
Corridor Infra Trust Management [Member]      
Management Agreement [Line Items]      
Quarterly management fee percentage 0.25%    
Annual management fee percentage 1.00%    
Quarterly incentive fee percentage in relation to distribution threshold 10.00%    
Distribution threshold (in dollars per share) $ 0.625    
General and Administrative Expense [Member] | Corridor Infra Trust Management [Member]      
Management Agreement [Line Items]      
Management Fee $ 7,200 $ 7,200 $ 5,700
Administrative Fee 269 266 224
New Management Agreement [Member]      
Management Agreement [Line Items]      
Incentive fees waived 100 88 133
Incentive Fee $ 595 $ 595 279
Payments for other fees     $ 145
Administrative Agreement [Member]      
Management Agreement [Line Items]      
Annual rate percentage of managed assets 0.04%    
Minimum annual fee $ 30