Correction of Errors in Previously Reported Financial Statements, (Details 1) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Continuing Operations
Net sales	$ 943,796	[1]	$ 826,277	[1]	$ 687,485	[1]
Cost of sales	691,479	[1]	612,092	[1]	503,194	[1]
Gross profit	252,317	[1]	214,185	[1]	184,291	[1]
Selling, general and administrative expenses	166,231	[1]	145,173	[1]	134,947	[1]
Operating profit	86,086	[1]	69,012	[1]	49,344	[1]
Other income (expense):
Interest expense, net	(11,070)	[1]	(9,584)	[1]	(11,994)	[1]
Other, net	233	[1]	1,241	[1]	(315)	[1]
Total other income (expense), net	(10,837)	[1]	(8,343)	[1]	(12,309)	[1]
Income before income taxes and income (loss) from affiliates and joint ventures	75,249	[1]	60,669	[1]	37,035	[1]
Income tax expense (benefit)	20,786	[1]	20,302	[1]	5,363	[1]
Income before income (loss) from affiliates and joint ventures	54,463	[1]	40,367	[1]	31,672	[1]
Income (loss) from affiliates and joint ventures	5,235	[1]	(10,997)	[1]	6	[1]
Income (loss) from continuing operations	59,698	[1]	29,370	[1]	31,678	[1]
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	(1,162)	[1]	(887)	[1]	259	[1]
Net income (loss)	58,536	[1]	28,483	[1]	31,937	[1]
Net income (loss) attributable to noncontrolling interests	15	[1]	(752)	[1]	(105)	[1]
Net income (loss) attributable to AMCOL shareholders	58,521	[1]	29,235	[1]	32,042	[1]
Weighted average common shares outstanding (in shares)	31,708,949	[1]	31,178,813	[1]	30,764,282
Weighted average common and common equivalent shares outstanding (in shares)	32,145,773	[1]	31,547,591	[1]	31,033,714
Amounts attributable to AMCOL shareholders
Income from continuing operations, net of tax	59,683	[1]	30,122	[1]	31,783	[1]
Discontinued operations, net of tax	(1,162)	[1]	(887)	[1]	259	[1]
Net income	58,521	[1]	29,235	[1]	32,042	[1]
Basic earnings (loss) per share
Continuing operations (in dollars per share)	$ 1.88	[1]	$ 0.97	[1]	$ 1.03	[1]
Discontinued operations (in dollars per share)	$ (0.04)	[1]	$ (0.03)	[1]	$ 0.01	[1]
Net income (in dollars per share)	$ 1.84	[1]	$ 0.94	[1]	$ 1.04	[1]
Diluted earnings (loss) per share
Continuing operations (in dollars per share)	$ 1.86	[1]	$ 0.96	[1]	$ 1.02	[1]
Discontinued operations (in dollars per share)	$ (0.04)	[1]	$ (0.03)	[1]	$ 0.01	[1]
Net income (in dollars per share)	$ 1.82	[1]	$ 0.93	[1]	$ 1.03	[1]
Previously reported [Member]
Continuing Operations
Net sales	942,400		841,000		691,900
Cost of sales	689,500		624,100		505,600
Gross profit	252,900		216,900		186,300
Selling, general and administrative expenses	165,200		146,900		133,400
Operating profit	87,700		70,000		52,900
Other income (expense):
Interest expense, net	(11,500)		(9,700)		(12,200)
Other, net	200		1,200		(900)
Total other income (expense), net	(11,300)		(8,500)		(13,100)
Income before income taxes and income (loss) from affiliates and joint ventures	76,400		61,500		39,800
Income tax expense (benefit)	21,800		19,400		5,300
Income before income (loss) from affiliates and joint ventures	54,600		42,100		34,500
Income (loss) from affiliates and joint ventures	5,500		(11,300)		100
Income (loss) from continuing operations	60,100		30,800		34,600
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	(900)		(900)		300
Net income (loss)	59,200		29,900		34,900
Net income (loss) attributable to noncontrolling interests	100		(500)		100
Net income (loss) attributable to AMCOL shareholders	59,100		30,400		34,800
Weighted average common shares outstanding (in shares)	31,700,000		31,200,000		30,800,000
Weighted average common and common equivalent shares outstanding (in shares)	32,100,000		31,500,000		31,000,000
Amounts attributable to AMCOL shareholders
Income from continuing operations, net of tax	60,000		31,300		34,500
Discontinued operations, net of tax	(900)		(900)		300
Net income	59,100		30,400		34,800
Basic earnings (loss) per share
Continuing operations (in dollars per share)	$ 1.89		$ 1.00		$ 1.12
Discontinued operations (in dollars per share)	$ (0.03)		$ (0.03)		$ 0.01
Net income (in dollars per share)	$ 1.86		$ 0.97		$ 1.13
Diluted earnings (loss) per share
Continuing operations (in dollars per share)	$ 1.87		$ 0.99		$ 1.11
Discontinued operations (in dollars per share)	$ (0.03)		$ (0.03)		$ 0.01
Net income (in dollars per share)	$ 1.84		$ 0.96		$ 1.12
Adjustments [Member]
Continuing Operations
Net sales	1,400		(14,700)		(4,400)
Cost of sales	1,900		(12,000)		(2,400)
Gross profit	(500)		(2,700)		(2,000)
Selling, general and administrative expenses	1,100		(1,700)		1,600
Operating profit	(1,600)		(1,000)		(3,600)
Other income (expense):
Interest expense, net	500		100		200
Other, net	0		100		600
Total other income (expense), net	500		200		800
Income before income taxes and income (loss) from affiliates and joint ventures	(1,100)		(800)		(2,800)
Income tax expense (benefit)	(1,000)		900		100
Income before income (loss) from affiliates and joint ventures	(100)		(1,700)		(2,900)
Income (loss) from affiliates and joint ventures	(300)		300		(100)
Income (loss) from continuing operations	(400)		(1,400)		(3,000)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	(300)		0		0
Net income (loss)	(700)		(1,400)		(3,000)
Net income (loss) attributable to noncontrolling interests	(100)		(200)		(200)
Net income (loss) attributable to AMCOL shareholders	(600)		(1,200)		(2,800)
Weighted average common shares outstanding (in shares)	31,700,000		31,200,000		30,800,000
Weighted average common and common equivalent shares outstanding (in shares)	32,100,000		31,500,000		31,000,000
Amounts attributable to AMCOL shareholders
Income from continuing operations, net of tax	(300)		(1,200)		(2,800)
Discontinued operations, net of tax	(300)		0		0
Net income	(600)		(1,200)		(2,800)
Basic earnings (loss) per share
Continuing operations (in dollars per share)	$ (0.01)		$ (0.03)		$ (0.09)
Discontinued operations (in dollars per share)	$ (0.01)		$ 0		$ 0
Net income (in dollars per share)	$ (0.02)		$ (0.03)		$ (0.09)
Diluted earnings (loss) per share
Continuing operations (in dollars per share)	$ (0.01)		$ (0.04)		$ (0.09)
Discontinued operations (in dollars per share)	$ (0.01)		$ 0		$ 0
Net income (in dollars per share)	$ (0.02)		$ (0.04)		$ (0.09)
Tax [Member] | Adjustments [Member]
Continuing Operations
Net sales	0		0		0
Cost of sales	0				0
Gross profit	0		0		0
Selling, general and administrative expenses	0
Operating profit	0		0		0
Other income (expense):
Interest expense, net	0				0
Other, net	0				0
Total other income (expense), net	0		0		0
Income before income taxes and income (loss) from affiliates and joint ventures	0		0		0
Income tax expense (benefit)	(1,800)		600		500
Income before income (loss) from affiliates and joint ventures	1,800		(600)		(500)
Income (loss) from affiliates and joint ventures	(300)
Income (loss) from continuing operations	1,500		(600)		(500)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	0				0
Net income (loss)	1,500		(600)		(500)
Net income (loss) attributable to noncontrolling interests	0				0
Net income (loss) attributable to AMCOL shareholders	1,500		(600)		(500)
Other [Member] | Adjustments [Member]
Continuing Operations
Net sales	800		(14,000)		(4,300)
Cost of sales	(200)		(12,700)		(3,800)
Gross profit	1,000		(1,300)		(500)
Selling, general and administrative expenses	(100)		(1,400)		1,300
Operating profit	1,100		100		(1,800)
Other income (expense):
Interest expense, net	500		100		200
Other, net	0		100		600
Total other income (expense), net	500		200		800
Income before income taxes and income (loss) from affiliates and joint ventures	1,600		300		(1,000)
Income tax expense (benefit)	800		300		(100)
Income before income (loss) from affiliates and joint ventures	800		0		(900)
Income (loss) from affiliates and joint ventures	0		300		(100)
Income (loss) from continuing operations	800		300		(1,000)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	(300)		0		0
Net income (loss)	500		300		(1,000)
Net income (loss) attributable to noncontrolling interests	0		(200)		0
Net income (loss) attributable to AMCOL shareholders	500		500		(1,000)
Spain [Member] | Adjustments [Member]
Continuing Operations
Net sales	0		0		0
Cost of sales	1,200		600		700
Gross profit	(1,200)		(600)		(700)
Selling, general and administrative expenses	100				300
Operating profit	(1,300)		(600)		(1,000)
Other income (expense):
Interest expense, net					0
Other, net					0
Total other income (expense), net	0		0		0
Income before income taxes and income (loss) from affiliates and joint ventures	(1,300)		(600)		(1,000)
Income tax expense (benefit)	(200)				(200)
Income before income (loss) from affiliates and joint ventures	(1,100)		(600)		(800)
Income (loss) from affiliates and joint ventures	0
Income (loss) from continuing operations	(1,100)		(600)		(800)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	0				0
Net income (loss)	(1,100)		(600)		(800)
Net income (loss) attributable to noncontrolling interests	0				0
Net income (loss) attributable to AMCOL shareholders	(1,100)		(600)		(800)
Poland [Member]
Continuing Operations
Net sales					(100)
Cost of sales					200
Gross profit					(300)
Operating profit					(300)
Other income (expense):
Interest expense, net					0
Other, net					0
Total other income (expense), net					0
Income before income taxes and income (loss) from affiliates and joint ventures					(300)
Income before income (loss) from affiliates and joint ventures					(300)
Income (loss) from continuing operations					(300)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations					0
Net income (loss)					(300)
Net income (loss) attributable to noncontrolling interests					0
Net income (loss) attributable to AMCOL shareholders					(300)
Poland [Member] | Adjustments [Member]
Continuing Operations
Net sales	0		(100)
Cost of sales	600		100
Gross profit	(600)		(200)
Selling, general and administrative expenses	600		100
Operating profit	(1,200)		(300)
Other income (expense):
Interest expense, net	0
Other, net	0
Total other income (expense), net	0		0
Income before income taxes and income (loss) from affiliates and joint ventures	(1,200)		(300)
Income tax expense (benefit)	0
Income before income (loss) from affiliates and joint ventures	(1,200)		(300)
Income (loss) from affiliates and joint ventures	0
Income (loss) from continuing operations	(1,200)		(300)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	0
Net income (loss)	(1,200)		(300)
Net income (loss) attributable to noncontrolling interests	0
Net income (loss) attributable to AMCOL shareholders	(1,200)		(300)
South Africa [Member] | Adjustments [Member]
Continuing Operations
Net sales	0		0		0
Cost of sales	300				500
Gross profit	(300)		0		(500)
Selling, general and administrative expenses	0		(100)		100
Operating profit	(300)		100		(600)
Other income (expense):
Interest expense, net	0				0
Other, net	0				0
Total other income (expense), net	0		0		0
Income before income taxes and income (loss) from affiliates and joint ventures	(300)		100		(600)
Income tax expense (benefit)	300		100		(100)
Income before income (loss) from affiliates and joint ventures	(600)		0		(500)
Income (loss) from affiliates and joint ventures	0
Income (loss) from continuing operations	(600)		0		(500)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	0				0
Net income (loss)	(600)		0		(500)
Net income (loss) attributable to noncontrolling interests	(100)				(200)
Net income (loss) attributable to AMCOL shareholders	(500)		0		(300)
Dong Ming [Member] | Adjustments [Member]
Continuing Operations
Net sales	0		0		0
Cost of sales	0				0
Gross profit	0		0		0
Selling, general and administrative expenses	700		(300)		(100)
Operating profit	(700)		300		100
Other income (expense):
Interest expense, net	0				0
Other, net	0				0
Total other income (expense), net	0		0		0
Income before income taxes and income (loss) from affiliates and joint ventures	(700)		300		100
Income tax expense (benefit)	(200)		100		0
Income before income (loss) from affiliates and joint ventures	(500)		200		100
Income (loss) from affiliates and joint ventures	0
Income (loss) from continuing operations	(500)		200		100
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	0				0
Net income (loss)	(500)		200		100
Net income (loss) attributable to noncontrolling interests	0				0
Net income (loss) attributable to AMCOL shareholders	(500)		200		100
Malaysia [Member] | Adjustments [Member]
Continuing Operations
Net sales	600		(600)
Cost of sales	0
Gross profit	600		(600)
Selling, general and administrative expenses	(200)
Operating profit	800		(600)
Other income (expense):
Interest expense, net	0
Other, net	0
Total other income (expense), net	0		0
Income before income taxes and income (loss) from affiliates and joint ventures	800		(600)
Income tax expense (benefit)	100		(200)
Income before income (loss) from affiliates and joint ventures	700		(400)
Income (loss) from affiliates and joint ventures	0
Income (loss) from continuing operations	700		(400)
Discontinued Operations [Abstract]
Income (loss) on discontinued operations	0
Net income (loss)	700		(400)
Net income (loss) attributable to noncontrolling interests	0
Net income (loss) attributable to AMCOL shareholders	$ 700		$ (400)

[1] Restated