Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Net sales	$ 341,289	$ 314,438	$ 649,717	$ 655,583
Cost of products sold	188,374	172,841	362,063	356,627
Gross profit	152,915	141,597	287,654	298,956
Selling, general and administrative	83,426	69,034	158,889	149,271
Research and development	13,970	13,760	27,204	27,872
Restructuring charges (Note 3)	7,078	8,865	8,385	10,872
Currency exchange losses (gains), net (Note 5)	1,640	793	(459)	1,063
Product liability expense (Note 17)	11,751	851	14,547	2,802
Operating income	35,050	48,294	79,088	107,076
Interest expense	2,172	2,459	4,082	5,602
Other income, net	(2,293)	(2,000)	(6,506)	(3,258)
Total other (income) expense, net	(121)	459	(2,424)	2,344
Income before income taxes	35,171	47,835	81,512	104,732
Provision for income taxes (Note 9)	9,784	11,429	19,525	24,523
Net income	25,387	36,406	61,987	80,209
Net income attributable to noncontrolling interests	(262)	(340)	(448)	(468)
Net income attributable to MSA Safety Incorporated	$ 25,125	$ 36,066	$ 61,539	$ 79,741
Earnings per share attributable to MSA Safety Incorporated common shareholders (Note 8):
Basic (in dollars per share)	$ 0.64	$ 0.93	$ 1.57	$ 2.05
Diluted (in dollars per share)	0.64	0.92	1.56	2.03
Dividends per common share (in dollars per share)	$ 0.44	$ 0.43	$ 0.87	$ 0.85