Selected Quarterly Financial Data (Unaudited) - Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 152,511	$ 280,130	$ 95,182	$ 70,826	$ 132,326	$ 236,699	$ 105,781	$ 93,004	$ 598,649	$ 567,810	$ 613,111
Gross profit	46,400	80,859	17,746	14,340	40,486	64,330	27,941	22,959	159,345	155,716	155,681
Income (loss) from operations	(10,761)	35,662	(18,649)	(24,041)	(4,418)	20,043	(12,140)	(35,658)	(17,789)	(32,173)	(64,158)
Income (loss) before provision (benefit) for income taxes	(19,629)	17,430	(21,896)	(29,372)	(2,100)	17,652	(16,497)	(38,529)	(53,467)	(39,474)	(81,422)
Net income (loss)	(20,181)	16,414	(22,485)	(29,127)	(3,343)	15,699	(18,588)	(36,193)	(55,379)	(42,425)	(83,028)
Net income (loss) attributable to JAKKS Pacific, Inc.	$ (20,293)	$ 16,445	$ (22,542)	$ (29,158)	$ (3,247)	$ 15,682	$ (18,559)	$ (36,244)	$ (55,548)	$ (42,368)	$ (83,085)
Basic earnings (loss) per share (in dollars per share)	$ (0.70)	$ 0.60	$ (0.96)	$ (1.24)	$ (0.14)	$ 0.68	$ (0.80)	$ (1.57)
Weighted average shares outstanding (in shares)	29,617	27,085	23,600	23,557	23,106	23,106	23,106	23,100
Diluted earnings (loss) per share (in dollars per share)	$ (0.70)	$ 0.51	$ (0.96)	$ (1.24)	$ (0.14)	$ 0.38	$ (0.80)	$ (1.57)
Diluted weighted number of shares (in shares)	29,617	60,345	23,600	23,557	23,106	45,686	23,106	23,100