Commitments and Contingencies - Aggregate Amount of Guarantee Payments, Discharge Payments and Payments on Behalf of Borrowers (Parenthetical) (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2015 USD ($)
CUSO RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Recoveries from charged-off loans owed related to regular payments obligation	$ 290

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