Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Net Sales	$ 184,846	$ 176,797	$ 361,039	$ 354,435
Operating Income for Reportable Segments	37,704	33,501	72,216	67,131
Reconciliation from Segment Totals to Consolidated [Abstract]
Non-operating Expenses	(17,027)	(15,799)	(33,249)	(31,981)
Amortization	(884)	(719)	(1,763)	(1,465)
Operating income	19,793	16,983	37,204	33,685
Interest Expense	(762)	(1,151)	(1,506)	(2,325)
Interest Income	229	137	398	260
Other Income, Net	2,301	(134)	2,647	207
Income Before Taxes and Equity in Net Income of Associated Companies	21,561	15,835	38,743	31,827
Metalworking Process Chemicals [Member]
Segment Reporting Information [Line Items]
Net Sales	172,241	165,011	337,177	330,986
Operating Income for Reportable Segments	34,121	30,649	66,148	61,624
Coatings [Member]
Segment Reporting Information [Line Items]
Net Sales	12,185	10,950	22,931	21,473
Operating Income for Reportable Segments	3,616	2,799	6,122	5,312
All Other Segments [Member]
Segment Reporting Information [Line Items]
Net Sales	420	836	931	1,976
Operating Income for Reportable Segments	$ (33)	$ 53	$ (54)	$ 195