Condensed Consolidated Statement of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 304,392	$ 351,014	$ 959,975	$ 1,026,726
Cost of products sold	172,160	192,313	528,799	556,959
Gross profit	132,232	158,701	431,176	469,767
Selling, general and administrative	64,793	82,900	214,066	245,337
Research and development	13,851	13,520	41,723	41,482
Restructuring charges (Note 4)	7,603	1,850	18,475	11,203
Currency exchange losses (gains), net (Note 6)	2,759	(913)	3,821	17,338
Product liability expense (Note 17)	2,077	1,730	4,878	8,155
Operating income	41,149	59,614	148,213	146,252
Interest expense	2,305	4,259	7,907	11,089
Other income, net	(1,117)	(2,929)	(4,376)	(8,850)
Total other expense, net	1,188	1,330	3,531	2,239
Income before income taxes	39,961	58,284	144,682	144,013
Provision for income taxes (Note 10)	11,727	15,673	36,251	37,913
Net income	28,234	42,611	108,431	106,100
Net income attributable to noncontrolling interests	(200)	(372)	(668)	(822)
Net income attributable to MSA Safety Incorporated	$ 28,034	$ 42,239	$ 107,763	$ 105,278
Earnings per share attributable to MSA Safety Incorporated common shareholders (Note 9):
Basic (in dollars per share)	$ 0.72	$ 1.09	$ 2.77	$ 2.72
Diluted (in dollars per share)	0.71	1.08	2.74	2.69
Dividends per common share (in dollars per share)	$ 0.43	$ 0.42	$ 1.28	$ 1.22