Long-term Debt (Details) $ in Thousands	Mar. 31, 2016 USD ($)
Summary of future contractual minimum rental revenues required under non-cancellable operating leases for railcars
Remaining 9 months of 2016	$ 96,568
2017	114,799
2018	101,443
2019	83,094
2020	48,256
2021 and thereafter	64,485
Total	508,645
Lease Fleet Financing [Member]
Summary of future contractual minimum rental revenues required under non-cancellable operating leases for railcars
Remaining 9 months of 2016	61,674
2017	68,315
2018	55,097
2019	39,699
2020	21,073
2021 and thereafter	22,526
Total	$ 268,384