Leases - Total Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Amortization of Right-of-Use Assets	$ 440	$ 906
Interest on Lease Liabilities	100	213
Total Finance Lease Cost	540	1,119
Operating Lease Cost	27,727	57,011
Sublease Receipts	(1,039)	(1,771)
Total Lease Cost	28,267	58,130
Operating Lease Cost Classified within Operating Expenses
Lessee, Lease, Description [Line Items]
Operating Lease Cost	27,929	57,142
Operating Lease Cost Classified within Restructuring Expenses, Net
Lessee, Lease, Description [Line Items]
Operating Lease Cost	$ 837	$ 1,640