BUSINESS SEGMENT INFORMATION (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Dec. 31, 2011
Segment disclosure
Net sales	$ 235.5	[1]	$ 218.6	[1]
Operating profit (loss)	21.4	[1]	19.0	[1]
Assets	858.8	[1]			849.1	[1],[2]
Depreciation, depletion, and amortization	10.7	[1]	9.5	[1]
Capital expenditures	16.6	[1]	10.4	[1]
Research and development (income) expense	2.5	[1]	1.9	[1]
Minerals and materials [Member]
Segment disclosure
Net sales	125.2	[1]	115.8	[1]
Operating profit (loss)	21.5	[1]	16.0	[1]
Assets	437.1	[1]			430.8	[1]
Depreciation, depletion, and amortization	4.6	[1]	4.6	[1]
Capital expenditures	6.5	[1]	2.8	[1]
Research and development (income) expense	1.7	[1]	1.6	[1]
Environmental [Member]
Segment disclosure
Net sales	51.0	[1]	51.7	[1]
Operating profit (loss)	0.9	[1]	1.8	[1]
Assets	162.8	[1]			159.4	[1]
Depreciation, depletion, and amortization	1.4	[1]	1.3	[1]
Capital expenditures	2.6	[1]	0.7	[1]
Research and development (income) expense	0.6	[1]	0.5	[1]
Oilfield services [Member]
Segment disclosure
Net sales	55.3	[1]	45.6	[1]
Operating profit (loss)	4.8	[1]	5.8	[1]
Assets	189.9	[1]			194.7	[1]
Depreciation, depletion, and amortization	4.0	[1]	3.0	[1]
Capital expenditures	6.0	[1]	6.4	[1]
Research and development (income) expense	0.1	[1]	0	[1]
Transportation [Member]
Segment disclosure
Net sales	11.1	[1]	12.7	[1]
Operating profit (loss)	0.2	[1]	0.5	[1]
Assets	3.9	[1]			3.9	[1]
Depreciation, depletion, and amortization	0	[1]	0	[1]
Capital expenditures	0	[1]	0	[1]
Intersegment sales [Member]
Segment disclosure
Net sales	(7.1)	[1]	(7.2)	[1]
Corporate [Member]
Segment disclosure
Operating profit (loss)	(6.0)	[1]	(5.1)	[1]
Assets	65.1	[1]			60.3	[1]
Depreciation, depletion, and amortization	0.7	[1]	0.6	[1]
Capital expenditures	1.5	[1]	0.5	[1]
Research and development (income) expense	$ 0.1	[1]	$ (0.2)	[1]

[1] Restated

[2] Condensed from audited financial statements.