Leases - Components of Cost (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Finance lease cost:
Amortization of right-of-use asset	$ 661
Interest on lease liabilities	70
Total finance lease cost	731
Operating lease cost	36,454
Short-term lease cost	12,885
Total lease cost	$ 50,070