CONSOLIDATED STATEMENTS OF NET INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2018	Apr. 01, 2017
Income Statement [Abstract]
Service revenues, net	$ 328,669	$ 261,476
Product sales and other, net	79,554	67,587
Revenues, net	408,223	329,063
Cost of services	139,778	124,885
Cost of product sales and other	47,442	40,081
Cost of revenues	187,220	164,966
Gross profit	221,003	164,097
Marketing expenses	98,919	86,429
Selling, general and administrative expenses	60,011	47,435
Operating income	62,073	30,233
Interest expense	35,866	28,142
Other (income) expense, net	(235)	640
Income before income taxes	26,442	1,451
Benefit from income taxes	(12,617)	(9,128)
Net income	39,059	10,579
Net loss attributable to the noncontrolling interest	53	74
Net income attributable to Weight Watchers International, Inc.	$ 39,112	$ 10,653
Earnings Per Share attributable to Weight Watchers International, Inc.
Basic	$ 0.60	$ 0.17
Diluted	$ 0.56	$ 0.16
Weighted average common shares outstanding
Basic	65,123	63,978
Diluted	69,501	66,527

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

Name:	us-gaap_CostOfGoodsAndServicesSold
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate cost of goods produced and sold and services rendered during the reporting period.