Derivative Financial Instruments - Effect of Interest Rate Contracts and Interest Rate Swaps on Consolidated Statements of Income and Other Comprehensive Income (Details) - USD ($)	12 Months Ended
Apr. 30, 2016	Apr. 25, 2015	Apr. 26, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge ineffectiveness	$ 0	$ 0	$ 0
Accumulated other comprehensive gain (loss) expected to be reclassified into earnings over the next twelve months	(2,809,000)
Interest Rate Swap [Member] \| Other Income, Net [Member] \| Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effect of interest rate contracts	0	(23,343,000)	(5,660,000)
Interest Rate Swap [Member] \| Interest Expense [Member] \| Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effect of interest rate contracts	$ (2,817,000)	$ (56,000)	$ 194,000

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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