Leases - Net Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 34,290	$ 35,443	$ 107,424	$ 106,958
Variable lease cost	4,006	3,902	12,382	11,517
Sublease income	(6,777)	(10,205)	(28,587)	(30,767)
Total lease cost, net	31,519	29,140	91,219	87,708
Cash paid for amounts included in the measurement of operating lease liabilities	34,763	32,294	103,725	100,172
Cash receipts from sublease arrangements	9,592	9,000	28,512	25,131
Right-of-use assets obtained in exchange for new operating lease liabilities	527	38,571	19,061	67,756
Cost for subleasing activities	$ 10,500	$ 10,800	$ 31,700	$ 32,500