Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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This element represents the fair value of the noncontrolling interest in the acquiree at the acquisition date.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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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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Fair value at acquisition-date of the assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interests issued by the acquirer, including but not limited to, instruments or interests issued or issuable in consideration for the business combination.

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Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount of deferred tax liability attributable to taxable temporary difference assumed at the acquisition date that are classified as noncurrent.

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Amount of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit, acquired at the acquisition date.

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The amount of identifiable intangible assets recognized as of the acquisition date.

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The amount of property, plant, and equipment recognized as of the acquisition date.

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Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

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In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination.

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The cash inflow associated with the acquisition of business during the period (for example, cash that was held by the acquired business).

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The loss recognized on termination of a contract.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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The value of restricted shares issued as compensation, net of the value of shares for the payment of withholding taxes. This element is to be used only if shares are used in lieu of cash to satisfy all or a portion of withholding taxes.

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Business Acquisition Purchase Price Allocation Developed Websites

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Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss) Net of Tax, Net

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Acquisitions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands					3 Months Ended									12 Months Ended
	Jun. 27, 2016	Mar. 11, 2015	Apr. 16, 2014	Mar. 12, 2014	Dec. 31, 2016	Oct. 01, 2016	Jul. 02, 2016	Apr. 02, 2016	Jan. 02, 2016	Oct. 03, 2015	Jul. 04, 2015	Apr. 04, 2015	Mar. 29, 2014	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Business Acquisition
Business acquisition, purchase price allocation, goodwill					$ 166,138				$ 159,331					$ 166,138	$ 159,331
Gain related to acquisition														$ 0	$ 0	$ 10,540
Earnings per share, diluted					$ 0.20	$ 0.53	$ 0.46	$ (0.17)	$ (0.18)	$ 0.38	$ 0.49	$ (0.10)		$ 1.03	$ 0.56	$ 2.08
Weight Watchers of Greater Miami, Inc.
Business Acquisition
Business acquisition, purchase price allocation, net purchase price	$ 3,250
Business acquisition, net purchase price	2,898
Business acquisition, cash acquired	300
Business acquisition, assumed net liabilities	52
Business acquisition, purchase price allocation, goodwill	2,945
Weight Watchers of Greater Miami, Inc. \| Customer Relationships
Business Acquisition
Business acquisition, purchase price allocation, finite lived intangible assets	191
Weight Watchers of Greater Miami, Inc. \| Franchise Rights
Business Acquisition
Business acquisition, purchase price allocation, indefinite lived intangible assets	$ 114
Vigilantes do Peso Marketing Ltda
Business Acquisition
Business acquisition, net purchase price				$ 14,181
Business acquisition, cash acquired				$ 2,262
Percentage of ownership				35.00%
Percentage of ownership acquired				45.00%
Business acquisition, equity interest held immediately before acquisition				$ 12
Business acquisition, fair value of equity interest				11,029
Remeasurement gain on business acquisition				11,017
Business acquisition cost associated with settlement of royalty-free arrangement				477
Gain related to acquisition													$ 10,540
Gain related to acquisition, after-tax													$ 6,429
Earnings per share, diluted													$ 0.11
Business acquisition, fair value of noncontrolling interest				$ 6,157
Vigilantes do Peso Marketing Ltda \| Call and Put Option
Business Acquisition
Percentage of ownership				20.00%
Knowplicity, Inc.
Business Acquisition
Business acquisition, purchase price allocation, net purchase price			$ 8,977
Business acquisition, net purchase price			4,770
Business acquisition, cash acquired			11
Business acquisition, purchase price allocation, goodwill			6,204
Business acquisition, purchase price allocation, common stock issued			4,207
Business acquisition, purchase price allocation, website development			4,516
Business acquisition, purchase price allocation, prepaid expenses			4
Business acquisition, purchase price allocation, fixed assets			1
Business acquisition, purchase price allocation, deferred tax liabilities			$ 1,759
Weilos
Business Acquisition
Business acquisition, purchase price allocation, net purchase price		$ 6,674
Business acquisition, net purchase price		2,775
Business acquisition, assumed net liabilities		975
Business acquisition, purchase price allocation, goodwill		5,588
Business acquisition, purchase price allocation, finite lived intangible assets		1,741
Business acquisition, purchase price allocation, common stock issued		2,810
Business acquisition, purchase price allocation, fixed assets		24
Business acquisition, purchase price allocation, deferred tax liabilities		679
Business acquisition, purchase price allocation, restricted stock issued		114
Restricted shares issued to key employees		$ 908