Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Cash and cash equivalents (Note 2)	$ 117,302	$ 160,672
Trade receivables, less allowance for credit loss of $4,930 and $5,344	219,481	252,283
Inventories (Note 3)	249,449	197,819
Investments, short-term (Note 17)	48,972	74,982
Prepaid income taxes	41,098	26,185
Notes receivable, insurance companies (Note 18)	3,884	3,796
Prepaid expenses and other current assets	45,193	38,541
Total current assets	725,379	754,278
Property, plant and equipment, net (Note 5)	204,410	189,620
Operating lease assets, net	50,731	53,451
Prepaid pension cost (Note 15)	108,842	97,545
Deferred tax assets (Note 10)	44,587	35,665
Goodwill (Note 13)	636,113	443,272
Intangible assets, net (Note 13)	312,606	161,051
Notes receivable, insurance companies, noncurrent (Note 18)	44,330	48,540
Net investment in sales-type leases, noncurrent (Note 14)	27,202	0
Insurance receivable (Note 18) and other noncurrent assets	105,252	89,062
Total assets	2,259,452	1,872,484
Liabilities
Notes payable and current portion of long-term debt (Note 12)	20,000	20,000
Accounts payable	92,634	86,854
Employees’ compensation	48,307	40,277
Insurance and product liability (Note 18)	40,188	43,706
Income taxes payable (Note 10)	22,608	3,580
Other current liabilities	113,084	116,128
Total current liabilities	336,821	310,545
Long-term debt, net (Note 12)	592,742	287,157
Pensions and other employee benefits	199,486	208,068
Noncurrent operating lease liabilities	40,854	44,639
Deferred tax liabilities (Note 10)	49,898	10,916
Product liability (Note 18) and other noncurrent liabilities	215,474	201,268
Total liabilities	1,435,275	1,062,593
Equity
Preferred stock, 4.5% cumulative, $50 par value (Note 7)	3,569	3,569
Common stock, no par value (Note 7)	252,084	242,693
Treasury shares, at cost (Note 7)	(331,350)	(327,756)
Accumulated other comprehensive loss (Note 6)	(189,323)	(182,397)
Retained earnings	1,089,197	1,065,789
Total MSA Safety Incorporated shareholders' equity	824,177	801,898
Noncontrolling interests (Note 19)	0	7,993
Total shareholders’ equity	824,177	809,891
Total liabilities and shareholders’ equity	$ 2,259,452	$ 1,872,484