Leases - Supplemental Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Feb. 01, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating leases:
Operating lease right-of-use assets	$ 428,197			$ 0
Operating lease liabilities	87,669			0
Noncurrent operating lease liabilities	342,171			$ 0
Total operating lease liabilities	429,840	$ 15,900	$ 433,400
Finance leases:
Properties, plants and equipment, at cost	12,007
Accumulated amortization	(5,751)
Properties, plants and equipment, net	6,256
Accrued liabilities	1,641
Other long-term liabilities	4,645
Finance Lease, Liability	$ 6,286
Weighted average remaining lease term (in years)
Operating leases	8 years 4 months
Finance leases	8 years 5 months
Weighted average discount rate
Operating leases	4.30%
Finance leases	5.10%