Leases - Lease, costs (Details) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Leases [Abstract]
Operating lease cost	$ 3,072	$ 9,225
Total lease cost	3,072	9,225
Operating cash flows for operating leases	3,140	9,415
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 0	$ 47,389
Weighted average remaining lease term - operating leases (years)	5 years 2 months 12 days	5 years 2 months 12 days
Weighted average discount rate - operating leases	7.40%	7.40%