Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information [Line Items]
Net sales	$ 176,797	$ 167,792	$ 354,435	$ 327,657
Operating income for reportable segments	33,501	28,599	67,131	57,532
Reconciliation from Segment Totals to Consolidated [Abstract]
Non-operating expenses	(15,799)	(13,171)	(31,981)	(27,518)
Amortization	(719)	(487)	(1,465)	(973)
Operating income	16,983	14,941	33,685	29,041
Interest expense	(1,151)	(1,200)	(2,325)	(2,418)
Interest income	137	271	260	543
Other (expense) income, net	(134)	791	207	1,330
Income before taxes and equity in net income of associated companies	15,835	14,803	31,827	28,496
Metalworking Process Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	165,011	156,772	330,986	307,505
Operating income for reportable segments	30,649	26,149	61,624	53,084
Coatings [Member]
Segment Reporting Information [Line Items]
Net sales	10,950	10,487	21,473	18,969
Operating income for reportable segments	2,799	2,446	5,312	4,409
All Other Segments [Member]
Segment Reporting Information [Line Items]
Net sales	836	533	1,976	1,183
Operating income for reportable segments	$ 53	$ 4	$ 195	$ 39