Long-term Debt (Details) $ in Thousands	Mar. 31, 2017 USD ($)
Summary of future contractual minimum rental revenues required under non-cancellable operating leases for railcars
Remaining 9 months of 2017	$ 94,790
2018	116,668
2019	97,354
2020	61,192
2021	44,793
2022 and thereafter	69,598
Total	484,395
Lease Fleet Financing [Member]
Summary of future contractual minimum rental revenues required under non-cancellable operating leases for railcars
Remaining 9 months of 2017	51,863
2018	59,560
2019	44,473
2020	25,008
2021	15,799
2022 and thereafter	14,758
Total	$ 211,461