Litigation (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 Claims	Dec. 31, 2011 Claims
Schedule of loss contingencies by contingency
Total claims pending at the end of the period	300
Asbestos Claims [Member]
Schedule of loss contingencies by contingency
Total claims pending at the beginning of the period	8,145	8,081
New claims served	1,538	1,565
Claims dismissed	(1,420)	(1,225)
Claims settled	(256)	(276)
Total claims pending at the end of the period	8,007	8,145
Gross settlement and defense costs	$ 23,589,000	$ 22,767,000
Average gross settlement and defense costs per claim resolved	$ 14,070	$ 15,170