Marketable Securities - Available-for-Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Aug. 26, 2017	Aug. 27, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Marketable Securities, Amortized Cost Basis	$ 100,885	$ 98,166
Available-For-Sale Marketable Securities, Gross Unrealized Gains	152	266
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(164)	(81)
Available-For-Sale Marketable Securities, Fair Value	100,873	98,351
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Marketable Securities, Amortized Cost Basis	39,917	37,789
Available-For-Sale Marketable Securities, Gross Unrealized Gains	73	198
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(13)	(6)
Available-For-Sale Marketable Securities, Fair Value	39,977	37,981
Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Marketable Securities, Amortized Cost Basis	31,076	33,497
Available-For-Sale Marketable Securities, Gross Unrealized Gains	49	24
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(74)	(35)
Available-For-Sale Marketable Securities, Fair Value	31,051	33,486
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Marketable Securities, Amortized Cost Basis	4,850	6,865
Available-For-Sale Marketable Securities, Gross Unrealized Gains	2	18
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(42)	(29)
Available-For-Sale Marketable Securities, Fair Value	4,810	6,854
Asset-Backed Securities and Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Marketable Securities, Amortized Cost Basis	25,042	20,015
Available-For-Sale Marketable Securities, Gross Unrealized Gains	28	26
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(35)	(11)
Available-For-Sale Marketable Securities, Fair Value	$ 25,035	$ 20,030

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 2
-Subparagraph (c)
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
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