Commitments and Contingencies - Aggregate Amount of Guarantee Payments, Discharge Payments and Payments on Behalf of Borrowers (Parenthetical) (Detail) - CUSO RSA [Member] - USD ($) $ in Thousands	3 Months Ended	4 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Loss Contingencies [Line Items]
Deferred payments	$ 2,574		$ 3,402	$ 3,402
Recoveries of charged off loans not yet received	$ 351		$ 468	468	$ 475	$ 475
Recoveries of charged off loans received		$ 156		$ 521	$ 156

The amount of recoveries from charged-off loans that were owed to the reporting entity by the variable interest entity that were offset against amounts the reporting entity owed to the variable interest entity.

No definition available.

Name:	esi_RecoveriesOwedToReportingEntityOffsetAgainstAmountsOwedToVariableInterestEntity
Namespace Prefix:	esi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration