Quarterly Financial Information (Unaudited) - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 495,358	$ 446,728	$ 447,299	$ 398,262	$ 443,254	$ 381,694	$ 372,313	$ 330,692	$ 1,787,647	$ 1,527,953	$ 1,400,182
Gross profit	238,183	218,761	213,796	181,398	197,252	169,395	164,400	142,784	852,138	673,831	615,348
Net (loss) income attributable to MSA Safety Incorporated	$ 76,410	$ 65,256	$ 67,090	$ (150,173)	$ 51,489	$ 44,906	$ 47,693	$ 35,542	$ 58,583	$ 179,630	$ 21,340
Earnings per share
Basic (in dollars per share)	$ 1.94	$ 1.66	$ 1.71	$ (3.83)	$ 1.31	$ 1.15	$ 1.21	$ 0.90	$ 1.49	$ 4.58	$ 0.54
Diluted (in dollars per share)	$ 1.93	$ 1.65	$ 1.70	$ (3.83)	$ 1.31	$ 1.14	$ 1.21	$ 0.90	$ 1.48	$ 4.56	$ 0.54