Leases - Operating Lease Minimum Payments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due
2019	$ 2,770
2020	4,801
2021	4,179
2022	2,103
2023	953
Thereafter	5,054
Total undiscounted rental payments	19,860
Less imputed interest	(2,895)
Total lease liabilities	$ 16,965
Operating Leases Liabilities, Before Adoption
2019		$ 4,921
2020		4,801
2021		4,179
2022		2,103
2023		953
Thereafter		5,054
Total undiscounted rental payments		22,011
Less imputed interest		(3,289)
Total lease liabilities		$ 18,722