Operating Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease expense	$ 4,286	$ 12,783
Short-term lease expense	109	148
Variable lease expense	11	35
Sublease income	(70)	(246)
Total	$ 4,336	$ 12,720