CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 8,860	$ 13,982	$ (9,367)	$ 7,925
Other comprehensive gain (loss):
Foreign currency translation gain (loss)	2,857	4,990	1,737	(4,830)
Income tax (expense) benefit on foreign currency translation gain (loss)	(720)	(1,267)	(438)	1,232
Foreign currency translation gain (loss), net of taxes	2,137	3,723	1,299	(3,598)
Gain (loss) on derivatives	1,522	364	6,726	(12,592)
Income tax (expense) benefit on gain (loss) on derivatives	(383)	(93)	(1,694)	3,212
Gain (loss) on derivatives, net of taxes	1,139	271	5,032	(9,380)
Total other comprehensive gain (loss)	3,276	3,994	6,331	(12,978)
Comprehensive income (loss)	12,136	17,976	(3,036)	(5,053)
Net loss attributable to the noncontrolling interest		24		18
Foreign currency translation (gain) loss, net of taxes attributable to the noncontrolling interest		(3)		95
Comprehensive loss attributable to the noncontrolling interest		21		113
Comprehensive income (loss) attributable to WW International, Inc.	$ 12,136	$ 17,997	$ (3,036)	$ (4,940)