Quarterly Results (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary of Quarterly Results
Net sales	$ 233,661	$ 248,044	$ 242,876	$ 217,788	$ 219,387	$ 228,822	$ 218,825	$ 174,003	$ 942,369	$ 841,037	$ 691,864
Gross Profit	62,058	70,990	62,115	57,712	53,439	58,276	60,599	44,612	252,875	216,926	186,270
Operating profit	20,190	27,053	21,827	18,583	12,323	22,672	23,878	11,168	87,653	70,041	52,877
Income (loss) from continuing operations	13,783	20,490	13,565	12,324	(9,350)	17,439	16,380	6,342	60,162	30,811	34,612
Income (loss) on discontinued operations		(1,021)	192	(87)					(916)	(887)	259
Net income (loss)	13,783	19,469	13,757	12,237	(9,448)	17,307	16,240	5,825	59,246	29,924	34,871
Net income (loss) attributable to noncontrolling interests	87	44	3	1	(101)	(110)	92	(304)	135	(423)	72
Net income (loss) attributable to AMCOL shareholders									59,111	30,347	34,799
Basic earnings per share attributable to AMCOL shareholders (A)									$ 1.86	$ 0.97	$ 1.13
Diluted earnings per share attributable to AMCOL shareholders (A)									$ 1.84	$ 0.96	$ 1.12
AMCOL Shareholders [Member]
Summary of Quarterly Results
Net income (loss) attributable to AMCOL shareholders	13,696	19,425	13,755	12,235	(9,347)	17,417		6,128	59,111
Basic earnings per share attributable to AMCOL shareholders (A)	$ 0.43	$ 0.61	$ 0.43	$ 0.39	$ (0.30)	$ 0.56	$ 0.52	$ 0.20
Diluted earnings per share attributable to AMCOL shareholders (A)	$ 0.43	$ 0.60	$ 0.43	$ 0.38	$ (0.30)	$ 0.55	$ 0.51	$ 0.20
Minerals and Materials [Member]
Summary of Quarterly Results
Net sales	121,375	123,792	119,851	116,880	114,853	110,332	106,397	97,688	481,898	429,270	336,172
Gross Profit	30,933	32,475	26,989	28,461	23,474	23,949	27,340	24,210
Operating profit	18,102	20,110	14,699	16,171	11,607	12,341	16,326	14,306	69,082	54,580	34,789
Environmental [Member]
Summary of Quarterly Results
Net sales	52,873	69,543	73,263	50,706	52,356	67,744	63,271	37,227	246,385	220,598	203,231
Gross Profit	14,243	21,563	21,899	15,648	16,399	20,742	19,946	11,061
Operating profit	592	7,637	7,916	2,296	2,774	8,701	8,148	191	18,441	19,814	25,090
Oilfield Services [Member]
Summary of Quarterly Results
Net sales	53,876	50,175	44,837	44,744	43,569	41,204	39,644	30,204	193,632	154,621	119,821
Gross Profit	15,348	15,377	11,465	12,664	12,201	11,955	11,770	8,014
Operating profit	5,799	5,787	3,423	4,872	4,758	4,079	4,553	1,228	19,881	14,618	12,753
Transportation [Member]
Summary of Quarterly Results
Net sales	11,782	14,877	14,780	12,674	12,238	14,284	13,583	12,120	54,113	52,225	46,642
Gross Profit	1,323	1,775	1,640	1,403	1,365	1,630	1,543	1,327
Operating profit	321	770	685	465	466	754	699	511	2,241	24,302	2,163
Intersegment Sales/gross profit [Member]
Summary of Quarterly Results
Net sales	(6,245)	(10,343)	(9,855)	(7,216)	(3,629)	(4,742)	(4,070)	(3,236)	(33,659)	(15,677)	(14,002)
Gross Profit	211	(200)	122	(464)
Corporate [Member]
Summary of Quarterly Results
Operating profit	$ (4,624)	$ (7,251)	$ (4,896)	$ (5,221)	$ (7,282)	$ (3,203)	$ (5,848)	$ (5,068)	$ (21,992)	$ (21,401)	$ (21,918)