BUSINESS COMBINATION (Details)	3 Months Ended	6 Months Ended			3 Months Ended	6 Months Ended
	Jun. 30, 2012 USD ($)	Jun. 30, 2012 USD ($)	Jan. 04, 2013 Twoo USD ($)	Jan. 04, 2013 Twoo EUR (€)	Jun. 30, 2012 About Group USD ($)	Jun. 30, 2012 About Group USD ($)	Sep. 24, 2012 About Group USD ($) topic
Business Combination
Purchase price, cash paid			$ 25,000,000				$ 300,000,000
Potential additonal cash payment			109,000,000	83,200,000
Contingent consideration, fair value			40,800,000
Number of topics in the online liabrary							90,000
Business acquisition, net working capital							17,100,000
Pro forma financial information
Adjustment for amortization of intangible assets					4,500,000	9,500,000
Revenue	706,022,000	1,370,567,000
Net earnings attributable to IAC shareholders	$ 46,122,000	$ 81,813,000
Basic earnings per share attributable to IAC shareholders (in dollars per share)	$ 0.54	$ 0.97
Diluted earnings per share attributable to IAC shareholders (in dollars per share)	$ 0.50	$ 0.89