Earnings Per Share - Diluted (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings Per Share [Abstract]
Net income attributable to Quaker Chemical Corporation	$ 10,540	$ 9,841	$ 22,486	$ 20,441
Less: income allocated to participating securities	(100)	(180)	(288)	(380)
Net income available to common shareholders	$ 10,440	$ 9,661	$ 22,198	$ 20,061
Basic weighted average common shares outstanding	12,850,917	12,043,858	12,790,799	11,668,657
Effect of dilutive securities, employee stock options	80,913	174,919	88,838	175,905
Diluted weighted average common shares outstanding	12,931,830	12,218,777	12,879,637	11,844,562
Diluted earnings per common share	$ 0.81	$ 0.79	$ 1.72	$ 1.69