CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net earnings	$ 95,635	$ 40,561	$ 204,872	$ 118,858
Other comprehensive income (loss), net of tax:
Change in foreign currency translation adjustment	16,724	14,609	3,703	(4,940)
Change in net unrealized gains (losses) on available-for-sale securities (net of tax provision of $1,732 and $1,648 for the three and nine months ended September 30, 2013, respectively, and tax benefit of $6,220 and tax provision of $883 for the three and nine months ended September 30, 2012, respectively)	12,182	(8,758)	24,393	4,685
Net current period other comprehensive income (loss)	28,906	5,851	28,096	(255)
Comprehensive income	124,541	46,412	232,968	118,603
Comprehensive (income) loss attributable to noncontrolling interests	(2,039)	(2,026)	1,443	476
Comprehensive income attributable to IAC shareholders	$ 122,502	$ 44,386	$ 234,411	$ 119,079