Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Finance lease cost:
Amortization of lease assets	$ 202	$ 373
Interest on lease liabilities	17	21
Operating lease cost	29,737	30,358
Short-term lease cost	170,365	200,298
Total lease cost	$ 200,321	$ 231,050