REVENUES - Components of Revenue (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Revenues                      
Total revenues $ 33,798 $ 35,233 $ 33,564 $ 33,973 $ 23,419 $ 16,080 $ 10,735 $ 7,696 $ 136,568 $ 57,930 $ 19,530
Equipment Leasing                      
Revenues                      
Lease income                 64,883 27,681 9,284
Maintenance revenue                 17,286 5,964 2,242
Finance lease income                 8,747 10,013 7,781
Other revenue                 1,827 326 223
Total revenues                 92,743 43,984 19,530
Infrastructure                      
Revenues                      
Lease income                 4,620 1,325  
Rail revenues                 25,550 9,969  
Terminal services revenues                 13,655 2,652  
Total revenues                 43,825 13,946 0
Operating Segments | Reportable Subsegments | Equipment Leasing | Aviation Leasing                      
Revenues                      
Lease income                 42,924 14,991 4,282
Maintenance revenue                 17,286 5,964 2,242
Finance lease income                 0 0 0
Other revenue                 1,120 3 121
Total revenues                 61,330 20,958 6,645
Operating Segments | Reportable Subsegments | Equipment Leasing | Offshore Energy                      
Revenues                      
Lease income                 21,959 12,690 5,002
Maintenance revenue                 0 0 0
Finance lease income                 1,665 1,716 262
Other revenue                 607 224  
Total revenues                 24,231 14,630 5,264
Operating Segments | Reportable Subsegments | Equipment Leasing | Shipping Containers                      
Revenues                      
Lease income                 0 0 0
Maintenance revenue                 0 0 0
Finance lease income                 7,082 8,297 7,519
Other revenue                 100 99 102
Total revenues                 7,182 8,396 7,621
Operating Segments | Reportable Subsegments | Infrastructure | Jefferson Terminal                      
Revenues                      
Lease income                 4,620 1,325  
Rail revenues                 0 0  
Terminal services revenues                 13,655 2,652  
Total revenues                 18,275 3,977 0
Operating Segments | Reportable Subsegments | Infrastructure | Railroad                      
Revenues                      
Lease income                 0 0  
Rail revenues                 25,550 9,969  
Terminal services revenues                 0 0  
Total revenues                 $ 25,550 $ 9,969 $ 0