CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 119,447	$ 223,568	$ 163,317
Other comprehensive (loss) gain:
Foreign currency translation gain (loss)	3,676	(11,462)	9,848
Income tax (expense) benefit on foreign currency translation gain (loss)	(939)	2,906	(3,840)
Foreign currency translation gain (loss), net of taxes	2,737	(8,556)	6,008
(Loss) gain on derivatives	(19,222)	7,205	17,393
Income tax benefit (expense) on (loss) gain on derivatives	4,868	(1,827)	(6,783)
(Loss) gain on derivatives, net of taxes	(14,354)	5,378	10,610
Total other comprehensive (loss) gain	(11,617)	(3,178)	16,618
Comprehensive income	107,830	220,390	179,935
Net loss attributable to the noncontrolling interest	169	181	197
Foreign currency translation loss, net of taxes attributable to the noncontrolling interest	22	373	35
Comprehensive loss attributable to the noncontrolling interest	191	554	232
Comprehensive income attributable to WW International, Inc.	$ 108,021	$ 220,944	$ 180,167