Commitments and Contingencies - Maturities of lease liabilities (Details) $ in Thousands	Jan. 25, 2020 USD ($)
Operating Leases
2021	$ 143,885
2022	142,382
2023	143,591
2024	143,485
2025	143,862
Thereafter	1,121,991
Total lease payments	1,839,196
Amount representing interest	(578,444)
Present value of lease liabilities	1,260,752
Less current obligations	(65,188)
Long-term lease obligations	1,195,564
Finance Leases
2021	424
2022	424
2023	390
2024	239
2025	243
Thereafter	162
Total lease payments	1,882
Less: amount representing interest	(349)
Present value of lease liabilities	1,533
Less current obligations	(314)
Long-term lease obligations	1,219
Total
2021	144,309
2022	142,806
2023	143,981
2024	143,724
2025	144,105
Thereafter	1,122,153
Total minimum lease payments	1,841,078
Less: amount representing interest	(578,793)
Present value of lease liabilities	1,262,285
Less current obligations	(65,502)
Long-term lease obligations	$ 1,196,783