Commitments and Contingencies - Loss Contingencies (Details) (USD $)	12 Months Ended	1 Months Ended		12 Months Ended
	Dec. 31, 2014 Users	Sep. 30, 2012 lawsuits Plaintiffs	Jan. 31, 2013 Plaintiffs	Dec. 31, 2013 Plaintiffs
Litigation and Other Legal Matters
Approximate number of users, Korean Subsidiary IAC	20,000,000
Approximate number of users sueing Korean Subsidiary IAC	149,000
September 2009, Seoul Korea District Court, Trial [Member]
Litigation and Other Legal Matters
Consolation money per user, Korean Court precedent	$ 200
January 2010 Seoul District Court [Member]
Litigation and Other Legal Matters
Approximate number of users sueing Korean Subsidiary IAC	34,000
September 2012, Seoul Korea High Court [Member]
Litigation and Other Legal Matters
Approximate number of users sueing Korean Subsidiary IAC		55
Number of representative suits in trial		3
January 2013, Seoul High Court [Member]
Litigation and Other Legal Matters
Approximate number of users sueing Korean Subsidiary IAC	33,795
Number of representative suits in trial	18
January 2013, Seoul Western District Court [Member]
Litigation and Other Legal Matters
Approximate number of users sueing Korean Subsidiary IAC			2,291
Litigation in Appeal [Member] | January 2013, Seoul High Court [Member]
Litigation and Other Legal Matters
Approximate number of users sueing Korean Subsidiary IAC	10			33,215
Number of representative suits in trial	2
Litigation in Appeal [Member] | Korean Supreme Court [Member]
Litigation and Other Legal Matters
Number of Users with Cases in Review	33,218
Litigation in Review [Member] | Korean Supreme Court [Member]
Litigation and Other Legal Matters
Number of representative suits in trial	11
Litigation in Review [Member] | January 2013, Seoul Western District Court [Member]
Litigation and Other Legal Matters
Approximate number of users sueing Korean Subsidiary IAC			2,284