UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS (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
Agency revenues	$ 1,064,640	$ 771,996	$ 1,834,568	$ 1,309,623
Merchant revenues	580,224	551,024	1,108,788	1,047,433
Advertising and other revenues	35,374	3,739	38,894	6,950
Total revenues	1,680,238	1,326,759	2,982,250	2,364,006
Cost of revenues	296,383	322,617	588,730	616,576
Gross profit	1,383,855	1,004,142	2,393,520	1,747,430
Operating expenses:
Advertising - Online	463,135	314,480	866,288	591,616
Advertising - Offline	32,130	9,922	59,859	21,078
Sales and marketing	59,855	47,445	112,118	92,982
Personnel, including stock-based compensation of $34,736, $17,612, $56,445 and $34,135, respectively	165,997	108,030	300,215	208,706
General and administrative	64,921	39,807	115,082	80,481
Information technology	16,959	10,440	30,181	21,175
Depreciation and amortization	26,027	15,663	45,107	31,505
Total operating expenses	829,024	545,787	1,528,850	1,047,543
Operating income	554,831	458,355	864,670	699,887
Other income (expense):
Interest income	1,141	1,001	2,015	2,099
Interest expense	(19,633)	(16,882)	(36,962)	(28,141)
Foreign currency transactions and other	(782)	3,205	(3,724)	829
Total other income (expense)	(19,274)	(12,676)	(38,671)	(25,213)
Earnings before income taxes	535,557	445,679	825,999	674,674
Income tax expense	98,117	93,025	144,267	140,204
Net income	437,440	352,654	681,732	534,470
Less: net income attributable to noncontrolling interests	114	307	135	153
Net income applicable to common stockholders	$ 437,326	$ 352,347	$ 681,597	$ 534,317
Net income applicable to common stockholders per basic common share (in dollars per share)	$ 8.62	$ 7.07	$ 13.54	$ 10.73
Weighted average number of basic common shares outstanding (in shares)	50,760	49,812	50,348	49,819
Net income applicable to common stockholders per diluted common share (in dollars per share)	$ 8.39	$ 6.88	$ 13.18	$ 10.41
Weighted average number of diluted common shares outstanding (in shares)	52,111	51,226	51,732	51,306