CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 75,041	$ 119,447	$ 223,568
Other comprehensive gain (loss):
Foreign currency translation gain (loss)	10,088	3,676	(11,462)
Income tax (expense) benefit on foreign currency translation gain (loss)	(2,533)	(939)	2,906
Foreign currency translation gain (loss), net of taxes	7,555	2,737	(8,556)
(Loss) gain on derivatives	(7,305)	(19,222)	7,205
Income tax benefit (expense) on (loss) gain on derivatives	1,855	4,868	(1,827)
(Loss) gain on derivatives, net of taxes	(5,450)	(14,354)	5,378
Total other comprehensive gain (loss)	2,105	(11,617)	(3,178)
Comprehensive income	77,146	107,830	220,390
Net loss attributable to the noncontrolling interest	38	169	181
Foreign currency translation loss, net of taxes attributable to the noncontrolling interest	98	22	373
Comprehensive loss attributable to the noncontrolling interest	136	191	554
Comprehensive income attributable to WW International, Inc.	$ 77,282	$ 108,021	$ 220,944