Commitments and Contingencies - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
Operating leases, 2019	$ 11,952
Operating leases, 2020	11,878
Operating leases, 2021	10,538
Operating leases, 2022	9,101
Operating leases, 2023	8,189
Operating leases, thereafter	10,677
Operating leases, future lease payments	62,335
Operating leases, amount representing interest	6,200
Operating leases, present value of future payments	56,135
Operating leases, short term leases not recorded as a liability	11,761
Operating leases, tenant incentives	3,186
Operating leases, revised present value of future payments	41,188
Operating leases, current portion	9,462
Operating lease, long-term portion	31,726
Sublease Income
Sublease Income, 2019	777
Sublease Income, 2020	791
Sublease Income, 2021	439
Sublease Income, 2022	0
Sublease Income, 2023	0
Sublease Income, thereafter	0
Sublease Income, future lease payments	2,007
Net Operating Leases
Net operating leases, 2019	11,175
Net operating leases, 2020	11,087
Net operating leases, 2021	10,099
Net operating leases, 2022	9,101
Net operating leases, 2023	8,189
Net operating leases, thereafter	10,677
Net operating leases, future lease payments	60,328
Operating leases, future lease payments	6,200
Net operating leases, present value of future payments	54,128
Net operating leases, short term leases not recorded as a liability	11,761
Net operating leases, tenant incentives	3,186
Net operating leases, revised present value of future payments	39,181
Net operating leases, revised, current portion	9,462
Net operating leases, revised, noncurrent portion	29,719
Finance Leases
Finance leases, 2019	10,060
Finance leases, 2020	5,453
Finance leases, 2021	3,587
Finance leases, 2022	1,568
Finance leases, 2023	60
Finance leases, thereafter	49
Finance leases, future lease payments	20,777
Finance leases, present value of future payments	1,072
Finance leases, present value of future payments	19,705
Finance lease obligations, current portion	9,459	$ 9,193
Finance lease obligations, net of current portion	$ 10,246	$ 9,992