Leases - Maturity of lease liabilities under finance and operating leases (Details) $ in Thousands	Aug. 31, 2019 USD ($)
Finance Leases, ASC842
2020 (remaining twenty-six weeks)	$ 9,482
2021	9,155
2022	4,275
2023	3,983
2024	3,711
Thereafter	18,660
Total lease payments	49,266
Less: imputed interest	(16,022)
Total finance lease liabilities, ASC842	33,244
Operating Leases, ASC842
2020 (remaining twenty-six weeks)	345,844
2021	645,871
2022	579,569
2023	524,643
2024	462,675
Thereafter	1,594,345
Total lease payments	4,152,947
Less: imputed interest	(904,643)
Total operating lease liabilities	3,248,304
Minimum sublease rentals	53,000
Operating and finance leases, ASC842
2020 (remaining thirty-nine weeks)	355,326
2021	655,026
2022	583,844
2023	528,626
2024	466,386
Thereafter	1,613,005
Total lease payments	4,202,213
Less: imputed interest	(920,665)
Total lease liabilities	$ 3,281,548