Variable Interest Entities - Schedule of Payments Made to Entity Related to Guarantee Obligations (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
Variable Interest Entity [Line Items]
Deferred payments	$ 2,574		$ 3,402	$ 3,402
Recoveries of charged off loans received		$ 156		521	$ 156
Recoveries of charged off loans not yet received	$ 351		$ 468	$ 468	$ 475	$ 475

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