Leases Leases - Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 1,137	$ 2,154
Sublease income	(95)	(137)
Net lease expense	$ 1,042	$ 2,017