Summary of Significant Accounting Policies - Leases Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accounting Policies [Abstract]
Operating lease cost	$ 135,086	$ 119,277	$ 267,761	$ 242,566
Depreciation of financing lease right-of-use assets	12,408	12,567	25,056	25,522
Interest expense for financing lease liabilities	4,910	4,929	9,885	9,773
Variable lease costs	$ 29,219	$ 26,996	$ 57,587	$ 54,801