Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 40,112	$ 33,421	$ 63,488	$ 65,910
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments (Note 6)	(385)	(27,880)	(24)	(14,480)
Pension and post-retirement plan actuarial gains, net of tax (Note 6)	1,378	3,059	3,401	5,388
Unrealized gains on available-for-sale securities (Note 6)	27	0	563	0
Reclassification of currency translation from accumulated other comprehensive (loss) into net income (Note 6)	0	(774)	15,359	(774)
Total other comprehensive income (loss), net of tax	1,020	(25,595)	19,299	(9,866)
Comprehensive income	41,132	7,826	82,787	56,044
Comprehensive (income) loss attributable to noncontrolling interests	(169)	31	(456)	(257)
Comprehensive income attributable to MSA Safety Incorporated	$ 40,963	$ 7,857	$ 82,331	$ 55,787