Leases - Summary of Future Lease Payments Under Non-Cancelable Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
2019	$ 6,806
2019			$ 9,394
2020	8,652		10,717
2021	2,520		4,706
2022	500		2,455
2023	509		2,389
Thereafter	3,100		23,940
Total lease payments	22,087		53,601
Less: imputed interest	(2,272)
Total operating lease liabilities	$ 19,815	$ 22,100	$ 53,601