Commitments and Contingencies - Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Minimum Lease Commitments
2018	$ 1,259
2019	1,127
2020	960
2021	789
2022 & thereafter	309
Total contractual obligations	4,444
Sublease Payments
2018	428
2019	399
2020	267
2021	134
2022 & thereafter	0
Total contractual obligations	1,228
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity, Net [Abstract]
2018	831
2019	728
2020	693
2021	655
2022 & thereafter	309
Total contractual obligations	$ 3,216