Commitments and Contingencies - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Operating Leases
Operating leases, 2019	$ 9,494
Operating leases, 2020	6,224
Operating leases, 2021	4,194
Operating leases, 2022	2,677
Operating leases, 2023	1,774
Operating leases, thereafter	25
Operating leases, future lease payments	24,388
Operating leases, future lease payments	(1,602)
Operating leases, present value of future payments	22,786
Operating leases, amont not on Balance Sheet	(748)
Operating leases, revised present value of future payments	22,038
Operating lease, current portion	(7,857)	$ (9,202)
Operating leases, long term portion	14,181
Sublease Income
Sublease income, 2019	774
Sublease income, 2020	787
Sublease income, 2021	639
Sublease income, 2022	0
Sublease income, 2023	0
Sublease income, thereafter	0
Sublease income, future payments	2,200
Net Operating Leases
Net operating leases, 2019	8,720
Net operating leases, 2020	5,437
Net operating leases, 2021	3,555
Net operating leases, 2022	2,677
Net operating leases, 2023	1,774
Net operating leases, thereafter	25
Net operating leases, future lease payments	22,188
Net operating leases, present value of future payments	20,586
Net operating leases, revised present value of future payments	19,838
Net operating leases, long term portion	11,981
Finance leases
Finance leases, 2019	9,742
Finance leases, 2020	4,806
Finance leases, 2021	3,103
Finance leases, 2022	1,503
Finance leases, 2023	57
Finance leases, thereafter	949
Finance leases, future lease payments	20,160
Finance leases, amount representing interest	(975)
Finance leases, present value of future payments	19,185
Finance lease obligations, current portion	(9,193)	(7,421)
Finance lease obligations, net of current portion	$ 9,992	$ 5,811