Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jul. 29, 2017	Apr. 29, 2017
Assets:
Cash equivalents	$ 1,901	$ 6,798
Deferred purchase price receivable	105,618	119,798
Derivative instruments	723	1,188
Total assets	108,242	127,784
Liabilities:
Derivative instruments	723	1,188
Fair Value, Inputs, Level 1
Assets:
Cash equivalents	1,901	6,798
Deferred purchase price receivable	0	0
Derivative instruments	0	0
Total assets	1,901	6,798
Liabilities:
Derivative instruments	0	0
Fair Value, Inputs, Level 2
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	0	0
Derivative instruments	723	1,188
Total assets	723	1,188
Liabilities:
Derivative instruments	723	1,188
Fair Value, Inputs, Level 3
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	105,618	119,798
Derivative instruments	0	0
Total assets	105,618	119,798
Liabilities:
Derivative instruments	$ 0	$ 0