Pro Forma Adjustments for Additional Amortization of That Would Have Been Recognized on the Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
Jun. 30, 2011	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Amortization of intangible assets		$ 17,655us-gaap_AmortizationOfIntangibleAssets	$ 9,477us-gaap_AmortizationOfIntangibleAssets	$ 4,071us-gaap_AmortizationOfIntangibleAssets
Stock-based compensation		9,393us-gaap_ShareBasedCompensation	4,933us-gaap_ShareBasedCompensation	2,364us-gaap_ShareBasedCompensation
Income tax benefit	(8,100)us-gaap_IncomeTaxExpenseBenefit	20,721us-gaap_IncomeTaxExpenseBenefit	8,142us-gaap_IncomeTaxExpenseBenefit	813us-gaap_IncomeTaxExpenseBenefit
GrubHub Holdings Inc \| Pro Forma
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Amortization of intangible assets			6,475
Stock-based compensation			2,997
Transaction costs			(9,131)
Income tax benefit			$ (3,050)

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-SubTopic 10

-Section 25

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- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Section 08

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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