Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

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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.

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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Number of shares of stock issued during the period pursuant to acquisitions.

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Acquisitions - Additional Information (Detail) (USD $)	12 Months Ended	0 Months Ended
Acquisitions - Additional Information (Detail) (USD $)	Dec. 31, 2013	Aug. 08, 2013	Dec. 31, 2014
Business Acquisition [Line Items]
Fair value of shares issued	$ 421,485,000
Compensation expense recognized in the post-Merger consolidated financial statements			19,200,000
Common stock
Business Acquisition [Line Items]
Business acquisitions, share issued	23,318,580
Preferred Stock
Business Acquisition [Line Items]
Business acquisitions, share issued	8,098,430
GrubHub Holdings Inc
Business Acquisition [Line Items]
Acquisition date		Aug. 08, 2013
Fair value of shares issued		421,485,000
GrubHub Holdings Inc \| General and administrative expenses
Business Acquisition [Line Items]
Direct and indirect expense incurred related to merger	4,700,000
GrubHub Holdings Inc \| Non-vested stock options
Business Acquisition [Line Items]
Fair value of shares issued		11,000,000
Compensation expense recognized in the post-Merger consolidated financial statements		$ 12,500,000
GrubHub Holdings Inc \| Common stock
Business Acquisition [Line Items]
Business acquisitions, share issued		23,318,580
GrubHub Holdings Inc \| Preferred Stock
Business Acquisition [Line Items]
Business acquisitions, share issued		8,098,430