NOTES PAYABLE (Details) $ in Thousands	Apr. 30, 2016 quarter	Apr. 29, 2017 USD ($)	Jul. 30, 2016 USD ($)	Apr. 29, 2016 USD ($)	May 28, 2014
Line of Credit Facility [Line Items]
Debt Instrument, Fee Amount	0.125%
Notes Payable		$ 304,187	$ 426,519
CANADA
Line of Credit Facility [Line Items]
Maximum Borrowing Base				$ 50,000
UNITED STATES
Line of Credit Facility [Line Items]
Maximum Borrowing Base				850,000
Minimum
Line of Credit Facility [Line Items]
Maximum Borrowing Base				10,000
Maximum
Line of Credit Facility [Line Items]
Maximum Borrowing Base				600,000
Amended and restated revolving credit facility
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.30%
Debt Instrument, Covenant Fixed Charge Coverage Ratio Minimum, Numerator	1.0
Debt Instrument, Covenant Fixed Charge Coverage Ratio Minimum, Denominator	1.0
Line of Credit Facility, Maximum Percentage of Aggregate Availability of the Aggregate Borrowing Base	10.00%
Amended and restated revolving credit facility | UNITED STATES | Federal Funds Effective Rate
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	federal funds effective rate
Debt Instrument, Basis Spread on Variable Rate	0.50%
Amended and restated revolving credit facility | UNITED STATES | LIBOR
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	LIBOR
initial applicable margin	1.25%
Amended and restated revolving credit facility | UNITED STATES | One-month LIBOR
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	one-month LIBOR
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.25%
Amended and restated revolving credit facility | UNITED STATES | Reuters Canadian Deposit Offering Rate
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	Reuters Canadian Deposit Offering Rate ("CDOR")
Debt Instrument, Basis Spread on Variable Rate	0.50%
Amended and restated revolving credit facility | UNITED STATES | Debt Instrument Variable Rate Bankers Acceptance Equivalent for One Month Interest Period [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	bankers' acceptance equivalent rate for a one month interest period
Amended and restated revolving credit facility | Minimum
Line of Credit Facility [Line Items]
Line of Credit Facility Percentage of Average Daily Balance of Amount Used	25.00%
Line of Credit Facility, Maximum Aggregate Availability of the Aggregate Borrowing Base				$ 60,000
Amended and restated revolving credit facility
Line of Credit Facility [Line Items]
Debt Instrument, Fixed Charge Coverage Ratio, Number of Quarters | quarter	4
Line of Credit, Amount of Reserves Affecting Current, Borrowing Capacity		5,900
Line of Credit Facility, Current Borrowing Capacity		882,900
Letters of Credit Outstanding, Amount		35,800
Line of Credit Facility, Remaining Borrowing Capacity		$ 542,900
Amended and restated revolving credit facility | CANADA
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.25%
Amended and restated revolving credit facility | UNITED STATES
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.25%
Debt Instrument Variable Rate One Month LIBOR [Member] | Amended and restated revolving credit facility | UNITED STATES
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Debt Instrument, Variable Rate LIBOR [Member] | Amended and restated revolving credit facility | UNITED STATES
Line of Credit Facility [Line Items]
Debt Instrument Initial Applicable Margin					1.25%