Leases - Schedule of leases assets and liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets:
Operating lease right-of-use assets	$ 20,349	$ 0
Liabilities:
Operating leases, short-term	6,039	0
Operating leases, long-term	18,769	$ 0
Total lease liabilities	$ 24,808