Leases - Supplemental Balance Sheet and Other Information (Details) - USD ($) $ in Thousands	Dec. 27, 2020	Sep. 27, 2020
Operating leases:
Right-of-use assets	$ 225,787	$ 239,396
Lease liabilities:
Current	69,612	69,650
Long-term	181,473	191,955
Total operating lease liabilities	$ 251,085	$ 261,605
Weighted-average remaining lease term:
Operating leases	5 years	5 years
Weighted-average discount rate:
Operating leases	2.50%	2.50%