Segments Table (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information Line Items
Net sales	$ 172,868	$ 180,923	$ 176,797	$ 177,638	$ 173,261	$ 182,313	$ 167,792	$ 159,865	$ 708,226	$ 683,231	$ 544,063
Operating income for reportable segments	126,971				119,505				126,971	119,505	105,443
Depreciation									11,594	10,889	9,736
Segment assets	536,634				511,152				536,634	511,152	452,868
Expenditures for long-lived assets									12,735	12,117	9,354
Metalworking Process Chemicals [Member]
Segment Reporting Information Line Items
Net sales									661,794	641,325	511,305
Operating income for reportable segments	116,013				110,118				116,013	110,118	98,427
Depreciation									10,834	10,222	9,150
Segment assets	514,513				489,615				514,513	489,615	433,821
Expenditures for long-lived assets									12,291	11,706	8,983
Coatings [Member]
Segment Reporting Information Line Items
Net sales									42,763	39,182	30,999
Operating income for reportable segments	10,654				9,275				10,654	9,275	7,093
Depreciation									700	624	555
Segment assets	21,406				20,644				21,406	20,644	18,201
Expenditures for long-lived assets									444	411	370
Other Chemical Products [Member]
Segment Reporting Information Line Items
Net sales									3,669	2,724	1,759
Operating income for reportable segments	304				112				304	112	(77)
Depreciation									60	43	31
Segment assets	715				893				715	893	846
Expenditures for long-lived assets									$ 0	$ 0	$ 1