EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator: Basic
Earnings from continuing operations	$ 150,261	$ 91,721	$ 166,571	$ 202,970
Net loss attributable to noncontrolling interests	821	1,305	4,082	3,995
Earnings from continuing operations attributable to IAC shareholders	151,082	93,026	170,653	206,965
Earnings from discontinued operations attributable to IAC shareholders	175,730	3,914	174,048	1,902
Net earnings attributable to IAC shareholders	326,812	96,940	344,701	208,867
Numerator: Diluted
Earnings from continuing operations	150,261	91,721	166,571	202,970
Net loss attributable to noncontrolling interests	821	1,305	4,082	3,995
Earnings from continuing operations attributable to IAC shareholders	151,082	93,026	170,653	206,965
Earnings from discontinued operations attributable to IAC shareholders	175,730	3,914	174,048	1,902
Net earnings attributable to IAC shareholders	$ 326,812	$ 96,940	$ 344,701	$ 208,867
Denominator: Basic
Weighted average basic shares outstanding	83,591	83,094	83,088	83,636
Denominator: Diluted
Weighted average basic shares outstanding	83,591	83,094	83,088	83,636
Dilutive securities including stock options and RSUs (in shares)	5,199	2,978	5,167	3,032
Denominator for earnings per share-weighted average shares (in shares)	88,790	86,072	88,255	86,668
Earnings (loss) per share attributable to IAC shareholders: Basic
Earnings per share from continuing operations (in dollars per share)	$ 1.81	$ 1.12	$ 2.05	$ 2.47
Discontinued operations (in dollars per share)	$ 2.10	$ 0.05	$ 2.10	$ 0.03
Earnings per share (in dollars per share)	$ 3.91	$ 1.17	$ 4.15	$ 2.50
Earnings (loss) per share attributable to IAC shareholders: Diluted
Earnings per share from continuing operations (in dollars per share)	$ 1.70	$ 1.08	$ 1.93	$ 2.39
Discontinued operations (in dollars per share)	$ 1.98	$ 0.05	$ 1.98	$ 0.02
Earnings per share (in dollars per share)	$ 3.68	$ 1.13	$ 3.91	$ 2.41