Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Apr. 30, 2016	Apr. 25, 2015
Assets:
Cash equivalents	$ 14,609	$ 90,569
Deferred purchase price receivable	108,837	89,588
Derivative instruments	816	1,255
Total assets	124,262	181,412
Liabilities:
Derivative instruments	816	1,255
Level 1 [Member]
Assets:
Cash equivalents	14,609	90,569
Deferred purchase price receivable	0	0
Derivative instruments	0	0
Total assets	14,609	90,569
Liabilities:
Derivative instruments	0	0
Level 2 [Member]
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	0	0
Derivative instruments	816	1,255
Total assets	816	1,255
Liabilities:
Derivative instruments	816	1,255
Level 3 [Member]
Assets:
Cash equivalents	0	0
Deferred purchase price receivable	108,837	89,588
Derivative instruments	0	0
Total assets	108,837	89,588
Liabilities:
Derivative instruments	$ 0	$ 0