The amount of cash collateral provided by the reporting entity for issued letters of credit.

No definition available.

Name:	esi_CashCollateralForLettersOfCredit
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of estimated future guarantee payments to be made under the 2009 Loan Program.

+ References

No definition available.

+ Details

Name:	esi_EstimatedFutureGuaranteePaymentsUnder2009LoanProgram
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of estimated future guarantee payments to be made under the PEAKS Program.

+ References

No definition available.

+ Details

Name:	esi_EstimatedFutureGuaranteePaymentUnderPeaksProgram
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total amount paid during the period for guarantee obligations, net of amounts recovered.

+ References

No definition available.

+ Details

Name:	esi_GuaranteeObligationsPaymentsNetOfRecoveries
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Payments made under the Guarantee related to the PEAKS Program.

+ References

No definition available.

+ Details

Name:	esi_GuaranteePaymentsRelatedToPEAKSProgram
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Date on which a letter of credit will terminate.

+ References

No definition available.

+ Details

Name:	esi_LetterOfCreditTerminationDate
Namespace Prefix:	esi_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Payments made on behalf of borrowers related to the PEAKS Program.

+ References

No definition available.

+ Details

Name:	esi_PaymentsOnBehalfOfBorrowers
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Recoveries From Charged Off Loans Owed Related To Regular Payments Obligation

+ References

No definition available.

+ Details

Name:	esi_RecoveriesFromChargedOffLoansOwedRelatedToRegularPaymentsObligation
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of the amount of certain issued letters of credit that are required to be collateralized with cash.

+ References

No definition available.

+ Details

Name:	esi_RequiredCashCollateralForLettersOfCredit1
Namespace Prefix:	esi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of the amount of certain issued letters of credit that are required to be collateralized with cash.

+ References

No definition available.

+ Details

Name:	esi_RequiredCashCollateralForLettersOfCredit2
Namespace Prefix:	esi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount borrowed under the credit facility as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityAmountOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Details

Name:	us-gaap_CreationDateAxis=esi_FuturePeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreationDateAxis=esi_FuturePeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=esi_AmendedCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=esi_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=esi_PeaksGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=esi_TwoThousandNineRiskShareAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Risks and Uncertainties - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		1 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jan. 31, 2014	Sep. 30, 2014	Dec. 31, 2014	Dec. 04, 2014
Unusual Risk or Uncertainty [Line Items]
Letter of credit termination date			Nov. 04, 2019
Cash collateral to be provided for letter of credit as of the filing date	$ 89,300esi_CashCollateralForLettersOfCredit		$ 89,300esi_CashCollateralForLettersOfCredit			$ 89,300esi_CashCollateralForLettersOfCredit
Payments on Behalf of Borrowers	0esi_PaymentsOnBehalfOfBorrowers	2,502esi_PaymentsOnBehalfOfBorrowers	1,832esi_PaymentsOnBehalfOfBorrowers	7,647esi_PaymentsOnBehalfOfBorrowers
Minimum [Member]
Unusual Risk or Uncertainty [Line Items]
Cash collateral, percentage	103.00%		103.00%			103.00%
Percentage of cash collateral amount equal to face amount	109.00%		109.00%			109.00%
PEAKS Guarantee [Member]
Unusual Risk or Uncertainty [Line Items]
Payments under PEAK Guarantee			159,300			2,700
Payments on Behalf of Borrowers			1,832		1,800
2009 RSA [Member]
Unusual Risk or Uncertainty [Line Items]
Net guarantee obligation payments	1,809	458	4,556	738
Subsequent Event [Member] \| PEAKS Guarantee [Member]
Unusual Risk or Uncertainty [Line Items]
Payments under PEAK Guarantee							161,100
Subsequent Event [Member] \| 2009 RSA [Member]
Unusual Risk or Uncertainty [Line Items]
Net guarantee obligation payments							9,139
Recoveries from charged-off loans							466
Amended Credit Agreement [Member]
Unusual Risk or Uncertainty [Line Items]
Outstanding borrowing under Amended Credit Agreement	50,000		50,000			50,000
Term Loan [Member]
Unusual Risk or Uncertainty [Line Items]
Cash collateral to be provided for letter of credit as of the filing date	100		100			100
Term Loan [Member] \| Subsequent Event [Member]
Unusual Risk or Uncertainty [Line Items]
Aggregate principal amount								100,000
2015 [Member] \| PEAKS Guarantee [Member] \| Scenario Forecast [Member]
Unusual Risk or Uncertainty [Line Items]
Payments under PEAKS guarantee			27,700
2015 [Member] \| 2009 RSA [Member] \| Scenario Forecast [Member]
Unusual Risk or Uncertainty [Line Items]
Payments under Loan Program			14,900
2016 [Member] \| PEAKS Guarantee [Member] \| Scenario Forecast [Member]
Unusual Risk or Uncertainty [Line Items]
Payments under PEAKS guarantee			4,800
2016 [Member] \| 2009 RSA [Member] \| Scenario Forecast [Member]
Unusual Risk or Uncertainty [Line Items]
Payments under Loan Program			$ 14,600