Segment Information - Worldwide Revenues by Brand Category (Detail) - USD ($) $ 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
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 1,473,705	$ 1,481,557	$ 860,063	$ 689,246	$ 1,524,281	$ 1,437,451	$ 844,706	$ 708,372	$ 4,504,571	$ 4,514,810	$ 4,881,493
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									5,064,574	5,075,529	5,514,125
Operating Segments | Barbie
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,159,768	1,088,953	954,892
Operating Segments | Hot Wheels
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									925,854	834,058	777,341
Operating Segments | Fisher-Price and Thomas & Friends
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,131,750	1,185,669	1,370,543
Operating Segments | Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,847,202	1,966,849	2,411,349
Sales adjustments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									$ (560,003)	$ (560,719)	$ (632,632)