Lease Commitments - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost (a)	$ 10,302	$ 20,920
Amortization of finance lease assets	55	109
Interest on finance lease liabilities	1	2
Total finance lease cost	56	111
Net lease cost	10,358	21,031
Short-term lease, cost	1,515	3,401
Variable lease, cost	844	1,680
Cost of Sales
Lessee, Lease, Description [Line Items]
Operating lease cost (a)	8,787	18,022
Selling, General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Operating lease cost (a)	$ 1,515	$ 2,898