Defined Contribution And Other Employee Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Union-Sponsored Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Costs related to union-sponsored defined contribution plan	$ 0.7	$ 0.8
Costs related to initial funding of union-sponsored defined contribution plan		0.6
ClevelandBakersAndTeamstersPensionFund [Member] \| Multiemployer Plans, Pension [Member]
Multiemployer Plans [Line Items]
Withdrawal payment		$ 17.0
Employer's contributions represent more than five percent of total contributions	true

The amount of the cost recognized during the period for initial funding of a defined contribution plan.

No definition available.

Name:	lanc_DefinedContributionPlanCostRecognizedInitialFunding
Namespace Prefix:	lanc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount paid as settlement of employer's portion of underfunded plan benefits due to withdrawal from a multiemployer plan. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

+ References

No definition available.

+ Details

Name:	lanc_MultiemployerPlansWithdrawalPayment
Namespace Prefix:	lanc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_MultiemployerPlansLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates (true/false) whether employer contributions represent more than five percent of total contributions to multiemployer plan for most recent plan year available.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (e)(2)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

+ Details

Name:	us-gaap_MultiemployerPlansPeriodContributionsSignificanceOfContributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanTypeAxis=lanc_UnionSponsoredPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MultiemployerPlanNameAxis=lanc_ClevelandBakersAndTeamstersPensionFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MultiemployerPlanTypeAxis=us-gaap_MultiemployerPlansPensionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: