Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 14, 2015	Jul. 04, 2015	Jun. 28, 2014	Jul. 04, 2015	Jun. 28, 2014	Dec. 31, 2015	Jan. 03, 2015	Dec. 28, 2013
Disclosure Basis Of Presentation Details [Line Items]
Long-term debt		$ 2,197,073		$ 2,197,073			$ 2,358,000
Cash and cash equivalents		149,722	$ 276,470	149,722	$ 276,470		$ 301,212	$ 174,557
Revenue		309,754	397,547	631,857	806,905
Income before income taxes		46,476	82,484	37,617	118,545
Net income attributable to Weight Watchers International, Inc.		27,877	$ 54,002	22,444	$ 75,533
Scenario, Forecast
Disclosure Basis Of Presentation Details [Line Items]
Revenue						$ 1,150,000
Out-of-Period Adjustments
Disclosure Basis Of Presentation Details [Line Items]
Income before income taxes				1,650
Net income attributable to Weight Watchers International, Inc.				420
Debt Obligations Due April 2016
Disclosure Basis Of Presentation Details [Line Items]
Long-term debt		$ 144,323		$ 144,323
Long-term debt, payment date				2016-04
Subsequent Event
Disclosure Basis Of Presentation Details [Line Items]
Credit facility drew down amount	$ 48,000