Consolidated Statements of Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Income Statement [Abstract]
Net sales		$ 1,400,182		$ 1,348,223		$ 1,401,981
Cost of products sold	[1]	784,834		752,731		763,352
Gross profit	[1]	615,348		595,492		638,629
Selling, general and administrative		332,862		290,334		330,502
Research and development		57,793		58,268		57,848
Restructuring charges (Note 3)		16,433		27,381		13,846
Currency exchange losses, net		216		8,578		19,814
Product liability (Note 20) and other operating expense		185,264		39,036		28,372
Operating income	[1]	22,780		171,895		188,247
Interest expense		10,758		9,432		13,589
Other income, net (Note 16)		(11,582)		(5,684)		(11,094)
Total other (income) expense, net		(824)		3,748		2,495
Income before income taxes	[1]	23,604		168,147		185,752
Provision for income taxes (Note 10)	[1]	1,816		43,009		46,545
Net income	[2]	21,788	[1]	125,138	[3]	139,207	[3]
Net income attributable to noncontrolling interests		(448)		(1,061)		(1,209)
Net income attributable to MSA Safety Incorporated	[1]	$ 21,340		$ 124,077		$ 137,998
Earnings per share attributable to MSA Safety Incorporated common shareholders (Note 9):
Basic (in dollars per share)	[1]	$ 0.54		$ 3.19		$ 3.56
Diluted (in dollars per share)	[1]	0.54		3.15		3.52
Dividends per common share (in dollars per share)		$ 1.75		$ 1.71		$ 1.64

[1] *Year ended December 31, 2020 and 2019 amounts have been adjusted to reflect the change in inventory accounting method, as described in Notes 1 and 4 to the consolidated financial statements.

[2] *Year ended December 31, 2020 and 2019 have been adjusted to reflect the change in inventory accounting method, as described in Notes 1 and 4.

[3] *Year ended December 31, 2020 and 2019 amounts have been adjusted to reflect the change in inventory accounting method, as described in Notes 1 and 4 to the consolidated financial statements.