Leases - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Amortization of lease assets	$ 825
Interest on lease liabilities	30
Operating lease cost	5,671
Finance Leases, Operating cash outflows	30
Operating Leases, Operating cash outflows	6,907
Finance Leases, Financing cash outflows	822
Right-of-use assets obtained in exchange for lease liabilities, Finance leases	1,739
Right-of-use assets obtained in exchange for lease liabilities, Operating leases	$ 862
Finance Lease, Weighted average remaining lease term (years)	2 years 10 months 24 days
Operating Lease, Weighted average remaining lease term (years)	8 years 6 months
Finance Leases, Weighted average discount rate	3.78%
Operating Leases, Weighted average discount rate		6.49%
Selling, General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 5,270
Cost of Services
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 401