Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	[2]	$ 21,788	[1]	$ 125,138	[3]	$ 139,207	[3]
Other comprehensive income, net of tax:
Foreign currency translation adjustments (Note 6)		(25,354)		22,260		(1,657)
Pension and post-retirement plan actuarial gains (losses), net of tax (Note 6)		58,256		9,296		(5,559)
Unrealized (losses) gains on available-for-sale securities (Note 6)		(4)		(7)		578
Reclassifications from accumulated other comprehensive (loss) into net income (Note 6)		267		216		15,261
Total other comprehensive income, net of tax		33,165		31,765		8,623
Comprehensive income	[3]	54,953		156,903		147,830
Comprehensive income attributable to noncontrolling interests		(356)		(1,220)		(1,136)
Comprehensive income attributable to MSA Safety Incorporated	[3]	$ 54,597		$ 155,683		$ 146,694

[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.