Condensed Consolidated Statements Of Comprehensive Income (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net income (loss)	$ 13,758	$ 16,241	$ 25,994	$ 22,065
Other comprehensive income (loss):
Foreign currency translation adjustment	443	(11,564)	2,356	(12,902)
Unrealized gain (loss) on available-for-sale securities, net of tax	(3,701)	1,318	(6,593)	(668)
Unrealized gain (loss) on interest rate swap agreements, net of tax	(807)	(1,788)	(350)	(2,374)
Pension adjustment, net of tax	25	34	50	64
Comprehensive income (loss)	9,718	4,241	21,457	6,185
AMCOL Shareholders [Member]
Net income (loss)	13,755	16,149	25,990	22,277
Other comprehensive income (loss):
Foreign currency translation adjustment	410	(11,508)	2,355	(12,838)
Unrealized gain (loss) on available-for-sale securities, net of tax	(3,701)	1,318	(6,593)	(668)
Unrealized gain (loss) on interest rate swap agreements, net of tax	(807)	(1,788)	(350)	(2,374)
Pension adjustment, net of tax	25	34	50	64
Comprehensive income (loss)	9,682	4,205	21,452	6,461
Noncontrolling Interest [Member]
Net income (loss)	3	92	4	(212)
Other comprehensive income (loss):
Foreign currency translation adjustment	33	(56)	1	(64)
Unrealized gain (loss) on available-for-sale securities, net of tax
Unrealized gain (loss) on interest rate swap agreements, net of tax
Pension adjustment, net of tax
Comprehensive income (loss)	$ 36	$ 36	$ 5	$ (276)