Business and Basis of Presentation - Net Lease Costs (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating lease cost	$ 36,046	$ 71,515
Variable lease cost	3,640	7,615
Sublease income	(10,289)	(20,562)
Total lease cost, net	29,397	58,568
Cash paid for amounts included in the measurement of operating lease liabilities	33,127	65,878
Cash receipts from sublease arrangements	8,303	16,131
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 27,799	$ 29,185
Weighted average remaining lease term for operating leases (in years)	10 years 7 months 6 days	10 years 7 months 6 days
Weighted average discount rate for operating leases	6.90%	6.90%
Cost for subleasing activities	$ 10,900	$ 21,700