Long-Term Debt - Acquisition Debt (Details) - USD ($) $ in Thousands					3 Months Ended	6 Months Ended
	Jun. 07, 2017	Sep. 27, 2016	Jun. 01, 2016	Apr. 01, 2014	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Long-term debt
Repayment of amounts outstanding under credit facility						$ 443,920	$ 635,732
Net amount of debt issued						577,616	481,225
Cash paid for interest						14,104	13,163
Write-off of debt discount and deferred financing fees					$ 1,466	$ 74	6,892
Term Loan Facilities, April 1, 2014
Long-term debt
Face amount of debt				$ 550,000
First Lien Term Loan due 2021
Long-term debt
Net amount of debt issued				388,100
Original issue discount				2,000
Loan repayment	$ 477,600
Second Lien Term Loan due 2022
Long-term debt
Net amount of debt issued				158,400
Original issue discount				$ 1,600
Loan repayment			$ 160,000				160,000
Write-off of debt discount and deferred financing fees			$ 5,400
Incremental First Lien Term Commitments Amendment
Long-term debt
Face amount of debt		$ 481,200
Reduction to interest rate margin at each pricing level (as a percent)		(25.00%)
Loan repayment		$ 381,200
Write-off of debt discount and deferred financing fees							1,500
Incremental First Lien Term Commitments Amendment | LIBOR
Long-term debt
Variable rate floor (as a percent)		1.00%
Margin added to variable rate (as a percent)		3.50%
Second amendment to First Lien Credit Agreement
Long-term debt
Face amount of debt	$ 577,600
Borrowing interest rate (as a percent)						4.38%
Reduction to interest rate margin at each pricing level (as a percent)	(50.00%)
Loan repayment						$ 477,616	$ 381,225
Write-off of debt discount and deferred financing fees						$ 100
Second amendment to First Lien Credit Agreement | LIBOR
Long-term debt
Variable rate floor (as a percent)	1.00%
Margin added to variable rate (as a percent)	3.00%
ABL Facility
Long-term debt
Loan repayment	$ 94,000