XML 63 R36.htm IDEA: XBRL DOCUMENT v3.10.0.1

Investments - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Debt Securities, Available-for-sale [Line Items]
Unrealized net (losses) gains on available-for-sale securities	$ (329)
Certificates of Deposit [Member]
Debt Securities, Available-for-sale [Line Items]
Maturity period of investments	One year or less

X

- Definition

Investment maturity period.

+ References

No definition available.

+ Details

Name:	lope_InvestmentMaturityPeriod
Namespace Prefix:	lope_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

+ Details

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

X

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

X

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: