Variable Interest Entities - Schedule of Payments Made to Entity Related to Guarantee Obligations (Parenthetical) (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2015 USD ($)
CUSO [Member]
Variable Interest Entity [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