Leases - Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 1,264	$ 3,418
Sublease income	(82)	(219)
Net lease expense	$ 1,182	$ 3,199