EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Numerator: Basic
Earnings from continuing operations	$ 58,540	$ 48,101	$ 111,249	$ 79,254
Net loss attributable to noncontrolling interests	818	(128)	2,690	(487)
Earnings from continuing operations attributable to IAC shareholders	59,358	47,973	113,939	78,767
Loss from discontinued operations attributable to IAC shareholders	(1,068)	(4,641)	(2,012)	(957)
Net earnings attributable to IAC shareholders	58,290	43,332	111,927	77,810
Numerator: Diluted
Earnings from continuing operations	58,540	48,101	111,249	79,254
Net loss attributable to noncontrolling interests	818	(128)	2,690	(487)
Earnings from continuing operations attributable to IAC shareholders	59,358	47,973	113,939	78,767
Loss from discontinued operations attributable to IAC shareholders	(1,068)	(4,641)	(2,012)	(957)
Net earnings attributable to IAC shareholders	$ 58,290	$ 43,332	$ 111,927	$ 77,810
Denominator: Basic
Weighted average basic shares outstanding	83,609	86,174	83,912	84,487
Denominator: Diluted
Weighted average basic shares outstanding	83,609	86,174	83,912	84,487
Dilutive securities including stock options, warrants and RSUs (in shares)	2,954	5,766	3,058	7,342
Denominator for earnings per share-weighted average shares (in shares)	86,563	91,940	86,970	91,829
Earnings (loss) per share attributable to IAC shareholders: Basic
Earnings per share from continuing operations (in dollars per share)	$ 0.71	$ 0.56	$ 1.36	$ 0.93
Discontinued operations (in dollars per share)	$ (0.01)	$ (0.06)	$ (0.03)	$ (0.01)
Earnings per share (in dollars per share)	$ 0.70	$ 0.50	$ 1.33	$ 0.92
Earnings (loss) per share attributable to IAC shareholders: Diluted
Earnings per share from continuing operations (in dollars per share)	$ 0.69	$ 0.52	$ 1.31	$ 0.86
Discontinued operations (in dollars per share)	$ (0.02)	$ (0.05)	$ (0.02)	$ (0.01)
Earnings per share (in dollars per share)	$ 0.67	$ 0.47	$ 1.29	$ 0.85