Leases - Supplemental cash flow information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash paid for amounts included in measurement of lease liabilities:
Operating cash flows from operating leases	$ 92,785	$ 96,752
Operating cash flows from finance leases	492	123
Financing cash flows from finance leases	4,469	1,224
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	67,000	113,253
Finance leases	10,340	7,636
Amortization of right of use operating lease assets	$ 85,266	$ 85,061