Leases - Elements of Lease Expense (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating lease cost	$ 1,277
Finance lease cost:
Amortization of right-of-use assets	3,370
Interest on lease liabilities	870
Total finance lease cost	4,240
Other lease income, net	(59)
Total lease cost	$ 5,458