Consolidated Statement Of Changes In Retained Earnings And Other Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Beginning Balance	$ 456,050
Net income	70,045	39,059	43,337
Ending Balance	439,411	456,050
Components of accumulated other comprehensive loss are as follows:
Cumulative translation adjustments	829	15,479	13,911
Pension and post-retirement plan adjustments	(104,013)	(59,795)	(59,767)
Accumulated other comprehensive loss	(103,184)	(44,316)	(45,856)
Retained Earnings [Member]
Beginning Balance	676,195	674,019	665,248
Net income	70,045	39,059	43,337
(Income) loss attributable to noncontrolling interests	(193)	(955)	(42)
Common dividends	(37,699)	(35,886)	(34,482)
Preferred dividends	(42)	(42)	(42)
Ending Balance	708,306	676,195	674,019
Accumulated Other Comprehensive (Loss) Income [Member]
Beginning Balance	(44,316)	(45,856)	(74,412)
Foreign currency translation adjustments	(15,980)	2,511	19,042
Pension and post-retirement plan adjustments, net of tax	(44,218)	(28)	10,895
(Income) loss attributable to noncontrolling interests	1,330	(943)	(1,381)
Ending Balance	(103,184)	(44,316)	(45,856)
Comprehensive Income (Loss) [Member]
Net income	70,045	39,059	43,337
Foreign currency translation adjustments	(15,980)	2,511	19,042
Pension and post-retirement plan adjustments, net of tax	(44,218)	(28)	10,895
Comprehensive income	9,847	41,542	73,274
(Income) loss attributable to noncontrolling interests	1,137	(1,898)	(1,423)
Comprehensive income attributable to Mine Safety Appliances Company	$ 10,984	$ 39,644	$ 71,851