Condensed Consolidated Statement of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 331,096	$ 296,129	$ 996,320	$ 850,669
Cost of products sold	182,794	163,926	546,844	465,780
Gross profit	148,302	132,203	449,476	384,889
Selling, general and administrative	78,013	72,852	240,226	223,741
Research and development	13,296	12,351	39,752	35,282
Restructuring charges (Note 5)	2,615	3,214	10,223	16,920
Currency exchange (gains) losses, net	(252)	562	2,571	3,994
Other operating expense (Note 19)	14,627	3,346	25,469	32,956
Operating income	40,003	39,878	131,235	71,996
Interest expense	4,492	3,961	14,454	10,566
Loss on extinguishment of debt (Note 13)	1,494	0	1,494	0
Other income, net	(4,252)	(1,720)	(8,292)	(4,406)
Total other expense, net	1,734	2,241	7,656	6,160
Income before income taxes	38,269	37,637	123,579	65,836
Provision for income taxes (Note 11)	4,206	5,411	23,606	6,306
Net income	34,063	32,226	99,973	59,530
Net income attributable to noncontrolling interests	(346)	(160)	(706)	(519)
Net income attributable to MSA Safety Incorporated	$ 33,717	$ 32,066	$ 99,267	$ 59,011
Earnings per share attributable to MSA Safety Incorporated common shareholders:
Basic	$ 0.88	$ 0.84	$ 2.59	$ 1.55
Diluted	0.86	0.83	2.55	1.52
Dividends per common share	$ 0.38	$ 0.35	$ 1.11	$ 1.03