Commitments and Contingencies - Minimum lease commitments 2019 (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Minimum lease commitments, Payments due by period:
2019	$ 2,450
2020	5,119
2021	2,439
2022	1,356
2023	865
Thereafter	551
Total future minimum lease payments	12,780
Less: Imputed interest	(1,174)
Total operating lease liabilities	11,606
Operating lease liability, current	$ 4,440
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued and Other Liabilities, Current
Operating lease liability, noncurrent	$ 7,166
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Operating lease liability, noncurrent
Total operating lease liabilities	$ 11,606