Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Apr. 29, 2017	Apr. 30, 2016
Assets:
Cash equivalents	$ 6,798	$ 14,609
Deferred purchase price receivable	119,798	108,837
Derivative instruments	1,188	816
Total assets	127,784	124,262
Liabilities:
Derivative instruments	1,188	816
Level 1 [Member]
Assets:
Cash equivalents	6,798	14,609
Deferred purchase price receivable	0	0
Derivative instruments	0	0
Total assets	6,798	14,609
Liabilities:
Derivative instruments	0	0
Level 2 [Member]
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	0	0
Derivative instruments	1,188	816
Total assets	1,188	816
Liabilities:
Derivative instruments	1,188	816
Level 3 [Member]
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	119,798	108,837
Derivative instruments	0	0
Total assets	119,798	108,837
Liabilities:
Derivative instruments	$ 0	$ 0