Leases - Lease Cost (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Lease Cost
Operating lease cost	$ 9,175
Sublease income	(1,111)
Short-term lease cost	5,998
Total lease cost	14,062
Operating cash flows from operating leases	$ 6,358
Weighted-average remaining lease term in years - operating leases	8 years 8 months 12 days
Weighted-average discount rate - operating leases	6.32%
Variable lease cost	$ 2,700