Condensed Consolidated Statement of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net sales	$ 308,428	$ 341,145
Cost of products sold	173,688	183,786
Gross profit	134,740	157,359
Selling, general and administrative	75,463	80,237
Research and development	13,234	14,112
Restructuring charges (Note 3)	1,308	2,007
Currency exchange (gains) losses, net (Note 5)	(2,099)	270
Product liability expense (Note 17)	2,796	1,951
Operating income	44,038	58,782
Interest expense	1,911	3,144
Other income, net	(4,213)	(1,259)
Total other (income) expense, net	(2,302)	1,885
Income before income taxes	46,340	56,897
Provision for income taxes (Note 9)	9,740	13,095
Net income	36,600	43,802
Net income attributable to noncontrolling interests	(186)	(128)
Net income attributable to MSA Safety Incorporated	$ 36,414	$ 43,674
Earnings per share attributable to MSA Safety Incorporated common shareholders (Note 8):
Basic (in dollars per share)	$ 0.93	$ 1.12
Diluted (in dollars per share)	0.92	1.11
Dividends per common share (in dollars per share)	$ 0.43	$ 0.42