Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Operating lease expense	$ 5,319	$ 4,987	$ 10,467	$ 10,031
Short-term lease expense	5,423	9,552	14,853	20,713
Total lease expense	$ 10,742	$ 14,539	$ 25,320	$ 30,744