Quarterly Results (Details Textual) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended							12 Months Ended	3 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010 Minerals and Materials [Member]	Sep. 30, 2010 Minerals and Materials [Member]	Dec. 31, 2010 CEO [Member]	Dec. 31, 2011 AMCOL Shareholders [Member]	Sep. 30, 2011 AMCOL Shareholders [Member]	Jun. 30, 2011 AMCOL Shareholders [Member]	Mar. 31, 2011 AMCOL Shareholders [Member]	Dec. 31, 2010 AMCOL Shareholders [Member]	Sep. 30, 2010 AMCOL Shareholders [Member]	Jun. 30, 2010 AMCOL Shareholders [Member]	Mar. 31, 2010 AMCOL Shareholders [Member]
Quarterly Results (Textual) [Abstract]
Segment recorded expenses									$ 2,779	$ 2,224
Increased (decreased) in net income attributable to AMCOL shareholders								(5,300)				(938)	106	(606)	848	(946)	(268)	35	67
Reduction to cost of sales								1,464
Income (loss) from affiliates and joint ventures					11,705			2,104
Increase in cost of sales	236	359	411	792
Increase in selling, general and administrative expenses	198	519
Increase in net sales				597
Reduction to sales					655	91
Increase (decrease) in income tax expense (benefit)			(1,399)	(482)	507	601	(472)
Expenses associated with retirement of CEO											2,665
Increase (decrease) in diluted earnings per share attributable to AMCOL shareholders	$ (0.03)	$ 0.01	$ 0.02	$ 0.03	$ (0.02)	$ (0.01)
Number of joint ventures								2
Tax expenses associated with foreign jurisdictions					$ 3,352