Stock Option Awards (Parenthetical) (Detail) (Officer)	Dec. 31, 2014
Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding stock	138,048

Number of outstanding options restricted on exercise of shares under restricted stock agreement.

No definition available.

Name:	grub_NumberOfOutstandingOptionsRestrictedOnExerciseOfSharesUnderRestrictedStockAgreement
Namespace Prefix:	grub_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant