2.4.0.840501 - Disclosure - Marketable Securities (Narrative) (Details)truefalseIn Millions, unless otherwise specifiedfalse1false USDfalsefalse$As_Of_6_30_2013http://www.sec.gov/CIK0001333513instant2013-06-30T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 1us-gaap_InvestmentsDebtAndEquitySecuritiesAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Marketable Securities [Abstract]2false 2us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasisus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse4380000043.8USD$falsetruefalsexbrli:monetaryItemTypemonetaryAmount of available-for-sale debt securities at cost, net of adjustments, maturing in the next rolling twelve months following the latest balance sheet presented. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.No definition available.false2Available-for-sale securities maturities of less than one yearfalseMarketable Securities (Narrative) (Details) (USD $)HundredThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.dealertrack.com/2010-09-30/role/DisclosureMarketableSecuritiesNarrativeDetails12