Note 9 - Reportable Segments Operations Information (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 24, 2016	Dec. 26, 2015	Sep. 24, 2016
Sales	$ 225,570	$ 222,850
Depreciation and amortization	9,911	9,625
Operating income	19,327	18,360
Capital expenditure	11,399	13,304
Assets	794,173	741,638	$ 790,487
Food Service [Member]
Sales	150,297	146,752
Depreciation and amortization	5,732	5,385
Operating income	17,054	15,902
Capital expenditure	6,587	8,084
Assets	594,963	546,264
Retail Supermarket [Member]
Sales	21,619	21,260
Depreciation and amortization	278	286
Operating income	1,046	1,090
Capital expenditure	82	156
Assets	22,128	23,099
Frozen Beverages [Member]
Sales	53,654	54,838
Depreciation and amortization	3,901	3,954
Operating income	1,227	1,368
Capital expenditure	4,730	5,064
Assets	177,082	172,275
Soft Pretzels [Member] \| Food Service [Member]
Sales	41,494	38,699
Soft Pretzels [Member] \| Retail Supermarket [Member]
Sales	8,944	8,740
Frozen Juices and Ices [Member] \| Food Service [Member]
Sales	7,479	8,315
Frozen Juices and Ices [Member] \| Retail Supermarket [Member]
Sales	9,851	9,064
Churros [Member] \| Food Service [Member]
Sales	14,438	13,936
Handhelds [Member] \| Food Service [Member]
Sales	7,479	6,146
Handhelds [Member] \| Retail Supermarket [Member]
Sales	3,450	3,875
Bakery [Member] \| Food Service [Member]
Sales	75,279	76,601
Other Products [Member] \| Food Service [Member]
Sales	4,128	3,055
Other Products [Member] \| Retail Supermarket [Member]
Sales	633	155
Other Products [Member] \| Frozen Beverages [Member]
Sales	248	273
Coupon Redemtion [Member] \| Retail Supermarket [Member]
Sales	(1,259)	(574)
Beverage [Member] \| Frozen Beverages [Member]
Sales	28,276	28,070
Repair and Maintenance Service [Member] \| Frozen Beverages [Member]
Sales	18,091	17,763
Machine Sales [Member] \| Frozen Beverages [Member]
Sales	$ 7,039	$ 8,732

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_Assets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

+ Details

Name:	us-gaap_DepreciationDepletionAndAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_OperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentAdditions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=jjsf_FoodServiceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=jjsf_RetailSupermarketMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=jjsf_FrozenBeveragesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_SoftPretzelsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_FrozenJuicesAndIcesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_ChurrosMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_HandheldsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_BakeryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_OtherProductsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_CouponRedemtionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_BeverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_RepairAndMaintenanceServiceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=jjsf_MachineSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: