Quarterly Results (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of Quarterly Results [Abstract]
Net sales	$ 257.5		$ 263.5		$ 258.8		$ 232.9		$ 235.6		$ 249.2		$ 251.4		$ 231.2		$ 1,012.7	$ 967.4	$ 926.3
Gross profit	65.4		17.5		70.6		62.1		60.8		68.7		72.7		63.3		215.6	265.5	247.5
Operating profit	19.2		(24.6)		24.9		16.3		18.0		28.5		30.4		20.9		35.8	97.8	86.0
Income (loss) from continuing operations	23.0		(22.5)		16.5		10.5		11.3		19.2		20.9		13.2		27.5	64.6	59.7
Income (loss) on discontinued operations	(0.2)		(4.1)		0.1		0		(0.3)		(0.2)		0.5		0.3		(4.2)	0.3	(1.2)
Net income (loss)	22.8		(26.6)		16.6		10.5		11.0		19.0		21.4		13.5		23.3	64.9	58.5
Net income (loss) attributable to noncontrolling interests	(0.1)		(6.8)		0		0		0		0		(0.3)		0.1		(6.9)	(0.2)	0
Net income (loss) attributable to AMCOL shareholders	22.9		(19.8)		16.6		10.5		11.0		19.0		21.7		13.4		30.2	65.1	58.5
Basic earnings per share attributable to AMCOL shareholders (in dollars per share)	$ 0.70	[1]	$ (0.61)	[1]	$ 0.51	[1]	$ 0.32	[1]	$ 0.34	[1]	$ 0.59	[1]	$ 0.67	[1]	$ 0.42	[1]	$ 0.93	$ 2.04	$ 1.84
Diluted earnings per share attributable to AMCOL shareholders (in dollars per share)	$ 0.70	[1]	$ (0.61)	[1]	$ 0.51	[1]	$ 0.32	[1]	$ 0.34	[1]	$ 0.59	[1]	$ 0.67	[1]	$ 0.41	[1]	$ 0.92	$ 2.01	$ 1.82
Performance Materials [Member]
Summary of Quarterly Results [Abstract]
Net sales	125.4		126.1		123.2		113.4		111.1		116.7		125.0		120.9		488.1	473.7	459.2
Gross profit	29.8		(19.4)		30.8		28.3		25.7		30.1		33.5		32.0
Operating profit	17.4		(32.1)		18.8		15.9		14.8		18.4		21.8		21.0		20.0	76.0	67.0
Construction Technologies [Member]
Summary of Quarterly Results [Abstract]
Net sales	56.5		62.8		56.0		42.8		50.1		60.6		61.4		51.0		218.1	223.1	251.9
Gross profit	16.2		21.5		17.9		13.1		15.1		20.1		18.7		14.6
Operating profit	3.7		9.3		2.8		(1.8)		1.3		7.0		6.3		1.0		14.0	15.6	17.3
Energy Services [Member]
Summary of Quarterly Results [Abstract]
Net sales	71.8		72.8		77.7		73.1		71.8		69.1		61.1		55.3		295.4	257.3	194.7
Gross profit	18.1		14.0		20.6		19.6		18.8		17.7		19.2		15.4
Operating profit	4.7		3.8		8.8		8.2		8.3		7.9		7.7		4.8		25.5	28.7	21.3
Transportation [Member]
Summary of Quarterly Results [Abstract]
Net sales	11.1		12.7		11.5		10.2		10.5		10.7		11.7		11.1
Gross profit	1.2		1.4		1.2		1.1		1.1		1.1		1.2		1.2
Operating profit	0.2		0.5		0.3		0.2		0.1		0.2		0.3		0.2
Intersegment Sales/Gross Profit [Member]
Summary of Quarterly Results [Abstract]
Net sales	(7.3)		(10.9)		(9.6)		(6.6)		(7.9)		(7.9)		(7.8)		(7.1)		(34.4)	(30.7)	(33.6)
Gross profit	0.1		0		0.1		0		0.1		(0.3)		0.1		0.1
Corporate [Member]
Summary of Quarterly Results [Abstract]
Operating profit	$ (6.8)		$ (6.1)		$ (5.8)		$ (6.2)		$ (6.5)		$ (5.0)		$ (5.7)		$ (6.1)		$ (24.9)	$ (23.3)	$ (21.8)

[1] Earnings per share (EPS) for each quarter is computed using the weighted-average number of shares outstanding during the quarter, while EPS for the year is computed using the weighted-average number of shares outstanding during the year.  Thus, the sum of the EPS for each of the four quarters may not equal the EPS for the year.