EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Numerator: Basic
Earnings from continuing operations	$ 31,153	$ 20,168
Net earnings attributable to noncontrolling interests	(359)	(150)
Earnings from continuing operations attributable to IAC shareholders	30,794	20,018
Earnings (loss) from discontinued operations, net of tax attributable to IAC shareholders	3,684	(1,948)
Net earnings attributable to IAC shareholders	34,478	18,070
Numerator: Diluted
Earnings from continuing operations	31,153	20,168
Net earnings attributable to noncontrolling interests	(359)	(150)
Earnings from continuing operations attributable to IAC shareholders	30,794	20,018
Earnings (loss) from discontinued operations, net of tax attributable to IAC shareholders	3,684	(1,948)
Net earnings attributable to IAC shareholders	$ 34,478	$ 18,070
Denominator: Basic
Weighted average basic shares outstanding	82,801	89,081
Denominator: Diluted
Weighted average basic shares outstanding	82,801	89,081
Dilutive securities including stock options, warrants and RSUs (in shares)	8,917	4,595
Denominator for earnings per share-weighted average shares (in shares)	91,718	93,676
Earnings (loss) per share attributable to IAC shareholders: Basic
Earnings per share from continuing operations (in dollars per share)	$ 0.37	$ 0.22
Discontinued operations, net of tax (in dollars per share)	$ 0.05	$ (0.02)
Earnings per share (in dollars per share)	$ 0.42	$ 0.20
Earnings (loss) per share attributable to IAC shareholders: Diluted
Earnings per share from continuing operations (in dollars per share)	$ 0.34	$ 0.21
Discontinued operations, net of tax (in dollars per share)	$ 0.04	$ (0.02)
Earnings per share (in dollars per share)	$ 0.38	$ 0.19