Comprehensive Income (Details) - USD ($) $ in Thousands	May 31, 2019	Nov. 30, 2018
Statement of Comprehensive Income [Abstract]
Terminated interest rate swap, net of tax benefit of $1,050 and $918, respectively	$ (795)	$ (1,204)
Accumulated other comprehensive income (loss), terminated interest rate swap, tax	$ 918	$ 1,050

Accumulated Other Comprehensive Income (Loss), Terminated Interest Rate Swap, Net of Tax

No definition available.

Name:	isca_AccumulatedOtherComprehensiveIncomeLossTerminatedInterestRateSwapNetOfTax
Namespace Prefix:	isca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant