Leases - Components of Lease Expense (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	$ 22,104	$ 26,181	$ 67,519	$ 79,829
Financing lease cost:
Amortization of right-of-use assets	426	355	1,329	932
Interest on lease liabilities	20	20	69	52
Total finance lease cost	446	375	1,398	984
Variable lease cost	9,342	10,588	28,652	30,337
Sublease income	(9,579)	(14,021)	(28,820)	(42,472)
Net lease cost	$ 22,313	$ 23,123	$ 68,749	$ 68,678