Capital Stock - Schedule of Common Stock Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Common Stock Activity [Roll Forward]
Beginning balance (in shares)	39,317,212
Stock options exercised (in shares)	10,666	31,394	103,545
Employee stock purchase plan expense	$ 186
Ending balance (in shares)	39,260,080	39,317,212
Common stock
Common Stock Activity [Roll Forward]
Beginning balance (in shares)	62,081,391	62,081,391	62,081,391
Ending balance (in shares)	62,081,391	62,081,391	62,081,391
Total MSA Safety Incorporated shareholders’ equity	$ 329,953	$ 312,324	$ 281,980	$ 260,121
Treasury Stock, Common
Common Stock Activity [Roll Forward]
Beginning balance (in shares)	22,764,179	22,868,327	22,804,873
Ending balance (in shares)	22,821,311	22,764,179	22,868,327
Total MSA Safety Incorporated shareholders’ equity	$ (396,604)	$ (361,684)	$ (359,838)	$ (328,776)
Restricted Stock | Common stock
Common Stock Activity [Roll Forward]
Restricted stock awards	(842)	(643)	(711)
Restricted stock expense	15,769	9,476	7,715
Restricted stock forfeitures	$ (4,530)	$ (1,414)	$ (1,227)
Restricted Stock | Treasury Stock, Common
Common Stock Activity [Roll Forward]
Restricted stock awards (in shares)	52,098	40,856	52,810
Restricted stock awards	$ 842	$ 643	$ 711
Stock options | Common stock
Common Stock Activity [Roll Forward]
Restricted stock expense	41	11	49
Restricted stock forfeitures	(41)	(11)
Stock options exercised	$ 327	$ 970	$ 3,021
Stock options | Treasury Stock, Common
Common Stock Activity [Roll Forward]
Stock options exercised (in shares)	10,666	31,394	103,545
Stock options exercised	$ 174	$ 503	$ 1,629
Performance stock | Common stock
Common Stock Activity [Roll Forward]
Restricted stock expense	8,394	23,546	15,843
Restricted stock forfeitures	(1,634)	(1,585)	(2,730)
Performance stock issued	$ (1,256)	$ (855)	$ (880)
Performance stock | Treasury Stock, Common
Common Stock Activity [Roll Forward]
Performance stock issued (in shares)	77,544	53,407	55,447
Performance stock issued	$ 1,256	$ 855	$ 880
Employee Stock Purchase Plan | Common stock
Common Stock Activity [Roll Forward]
Employee stock purchase plan shares issued	$ 1,215	$ 849	$ 779
Employee Stock Purchase Plan | Treasury Stock, Common
Common Stock Activity [Roll Forward]
Employee stock purchase plan (in shares)	8,871	7,140	7,412
Employee stock purchase plan shares issued	$ 148	$ 114	$ 112
Treasury shares purchased | Treasury Stock, Common
Common Stock Activity [Roll Forward]
Purchase of treasury shares (in shares)	40,019	28,649	31,260
Treasury shares purchased	$ (7,408)	$ (3,961)	$ (4,021)
Share repurchase program | Common stock
Common Stock Activity [Roll Forward]
Purchase of treasury shares (in shares)	0
Treasury shares purchased	$ 0
Share Repurchase Program | Treasury Stock, Common
Common Stock Activity [Roll Forward]
Restricted stock expense	$ (29,932)		$ (30,373)
Purchase of treasury shares (in shares)	(166,292)		(251,408)