CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Merchant revenues	$ 2,004,432	$ 1,691,640	$ 1,447,576
Agency revenues	2,339,253	1,380,603	868,395
Other revenues	11,925	12,662	22,241
Total revenues	4,355,610	3,084,905	2,338,212
Cost of revenues	1,275,730	1,175,934	1,077,449
Gross profit	3,079,880	1,908,971	1,260,763
Operating expenses:
Advertising - Online	919,214	552,140	365,381
Advertising - Offline	35,470	35,714	36,270
Sales and marketing	162,690	116,303	81,238
Personnel, including stock-based compensation of $65,724, $68,200, and $40,671, respectively	352,295	270,071	180,152
General and administrative	123,652	81,185	68,555
Information technology	33,813	20,998	19,139
Depreciation and amortization	53,824	45,763	39,193
Total operating expenses	1,680,958	1,122,174	789,928
Operating income	1,398,922	786,797	470,835
Other income (expense):
Interest income	8,119	3,857	2,223
Interest expense	(31,721)	(29,944)	(24,084)
Foreign currency transactions and other	(7,526)	(14,427)	(6,672)
Total other income (expense)	(31,128)	(40,514)	(28,533)
Earnings before income taxes and equity in income of investees	1,367,794	746,283	442,302
Income tax (expense) benefit	(308,663)	(218,141)	47,168
Equity in income of investees	0	0	2
Net income	1,059,131	528,142	489,472
Less: net income attributable to noncontrolling interests	2,760	601	0
Net income applicable to common stockholders	$ 1,056,371	$ 527,541	$ 489,472
Net income applicable to common stockholders per basic common share (in dollars per share)	$ 21.27	$ 11.00	$ 11.54
Weighted average number of basic common shares outstanding (in shares)	49,654	47,955	42,406
Net income applicable to common stockholders per diluted common share (in dollars per share)	$ 20.63	$ 10.35	$ 9.88
Weighted average number of diluted common shares outstanding (in shares)	51,211	50,988	49,522