Leases and Right of Use Assets - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease costs	$ 2,356	$ 4,515
Finance lease costs:
Amortization of assets	2,959	5,650
Interest on lease liabilities	603	1,149
Total finance lease costs	3,562	6,799
Variable and short-term lease costs	212	773
Total lease cost	$ 6,130	$ 12,087