CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Jan. 27, 2013	Jan. 22, 2012	Jan. 27, 2013	Jan. 22, 2012
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Deferred hedge adjustment, income tax provision	$ 90	$ 198	$ 268	$ 700
Unrealized gain on interest rate cap contracts, income tax provision	$ 0	$ 13	$ 8	$ 36

Tax effect on reclassification adjustment for accumulated gains and losses from interest rate swap contracts designated and qualifying as the effective portion of cash flow hedges included in accumulated comprehensive income that was realized in net income during the period.

No definition available.

Name:	isle_OtherComprehensiveIncomeReclassificationAdjustmentOnInterestRateSwapContractsIncludedInNetIncomeTax
Namespace Prefix:	isle_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration