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Represents the conversion ratio of number of shares exchanged in business combination.

No definition available.

Name:	stra_BusinessCombinationExchangeOfSharesConversionRatio
Namespace Prefix:	stra_
Data Type:	xbrli:sharesItemType
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Represents the number of independent universities.

No definition available.

Name:	stra_NumberOfIndependentUniversities
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Data Type:	xbrli:integerItemType
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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.

No definition available.

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableLineItems
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Data Type:	xbrli:stringItemType
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Number of shares of equity interests issued or issuable to acquire entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

No definition available.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
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-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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Data Type:	xbrli:monetaryItemType
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Name:	us-gaap_BusinessAcquisitionAxis=stra_NewYorkCodeAndDesignAcademyIncMember
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Data Type:	na
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Name:	us-gaap_BusinessAcquisitionAxis=stra_CapellaEducationCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_EquityInterestIssuedOrIssuableByTypeAxis=us-gaap_CommonStockMember
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