Schedule of Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings per share attributable to Mine Safety Appliances Company common shareholders
Net income attributable to Mine Safety Appliances Company	$ 24,049	$ 27,995	$ 43,335	$ 51,917
Preferred stock dividends	(10)	(10)	(20)	(20)
Income available to common equity	24,039	27,985	43,315	51,897
Dividends and undistributed earnings allocated to participating securities	(176)	(258)	(347)	(519)
Income available to Mine Safety Appliances Company common shareholders	$ 23,863	$ 27,727	$ 42,968	$ 51,378
Basic earnings per common share	$ 0.65	$ 0.76	$ 1.17	$ 1.41
Diluted earnings per common share	$ 0.64	$ 0.75	$ 1.15	$ 1.39
Basic shares outstanding	36,880	36,590	36,807	36,486
Stock options and other stock compensation	551	491	593	500
Diluted shares outstanding	37,431	37,081	37,400	36,986
Antidilutive stock options	188	410	188	410