Employee Benefit Plans - Summary of Changes in Benefit Obligation and Plan Assets for Defined Benefit Pension and Postretirement Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in Plan Assets:
Plan assets at fair value, beginning of year	$ 433,780
Plan assets at fair value, end of year	460,952	$ 433,780
Net Amount Recognized in Consolidated Balance Sheets:
Noncurrent accrued benefit liability	(168,539)	(192,466)
Amounts Recognized in Accumulated Other Comprehensive Loss:
Tax benefits related to changes in benefit obligation and plan assets which are also included in accumulated other comprehensive loss	81,200	85,700
Postretirement benefit plans
Change in Benefit Obligation:
Benefit obligation, beginning of year	605,851	611,490
Service cost	4,045	5,557	$ 6,105
Interest cost	17,961	24,526	26,007
Impact of currency exchange rate changes	12,932	(14,535)
Actuarial loss (gain)	32,817	25,164
Benefits paid	(34,314)	(46,425)
Plan amendments	27	74
Benefit obligation, end of year	639,319	605,851	611,490
Change in Plan Assets:
Plan assets at fair value, beginning of year	433,780	435,274
Actual return on plan assets	47,727	43,292
Employer contributions	4,807	17,617
Impact of currency exchange rate changes	8,952	(15,978)
Benefits paid	(34,314)	(46,425)
Plan assets at fair value, end of year	460,952	433,780	435,274
Net Amount Recognized in Consolidated Balance Sheets:
Funded status, end of year	(178,367)	(172,071)
Current accrued benefit liability	(16,180)	(4,519)
Noncurrent accrued benefit liability	(162,187)	(167,552)
Net amount recognized	(178,367)	(172,071)
Amounts Recognized in Accumulated Other Comprehensive Loss:
Net actuarial loss (gain)	243,295	243,249
Prior service cost (credit)	135	164
Total amount recognized in accumulated other comprehensive loss, before tax	243,430	243,413
Deferred compensation and excess benefit plans
Change in Benefit Obligation:
Benefit obligation, beginning of year	27,614	30,416
Service cost	2	52	54
Interest cost	812	1,143	1,194
Impact of currency exchange rate changes	0	0
Actuarial loss (gain)	(2,597)	(1,686)
Benefits paid	(1,818)	(2,311)
Plan amendments	(16,261)	0
Benefit obligation, end of year	7,752	27,614	30,416
Change in Plan Assets:
Plan assets at fair value, beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	1,818	2,311
Impact of currency exchange rate changes	0	0
Benefits paid	(1,818)	(2,311)
Plan assets at fair value, end of year	0	0	$ 0
Net Amount Recognized in Consolidated Balance Sheets:
Funded status, end of year	(7,752)	(27,614)
Current accrued benefit liability	(1,400)	(2,700)
Noncurrent accrued benefit liability	(6,352)	(24,914)
Net amount recognized	(7,752)	(27,614)
Amounts Recognized in Accumulated Other Comprehensive Loss:
Net actuarial loss (gain)	(2,795)	(49)
Prior service cost (credit)	(16,261)	0
Total amount recognized in accumulated other comprehensive loss, before tax	$ (19,056)	$ (49)

Tax benefits related to benefit plans included in accumulated other comprehensive loss

No definition available.

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Namespace Prefix:	mat_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The pretax total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.