Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities:
Net income	$ 129,287	$ 101,336
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment, including amortization of internal-use software and website development	13,200	8,996
Stock-based compensation	23,819	11,460
Amortization of intangible assets	2,739	3,599
Amortization of deferred financing costs	401	475
Amortization of discounts and premiums on marketable securities, net	2,637
Deferred tax benefit	(3,976)	(74)
Excess tax benefits from stock-based compensation	(5,242)	(2,011)
Provision (recovery) for doubtful accounts	656	(1,300)
Foreign currency transaction (gains) losses, net	2,539	2,323
Other, net	570	509
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	(55,685)	(27,455)
Related parties	(11,273)	(34,356)
Taxes receivable	6,171	(5,950)
Prepaid expenses and other assets	(6,884)	(1,879)
Accounts payable	(4,831)	7,268
Deferred merchant payables	15,535	900
Taxes payable	11,905	4,128
Accrued expenses and other liabilities	3,983	15,940
Deferred revenue	7,736	7,568
Net cash provided by operating activities	133,287	91,477
Investing activities:
Acquisitions, net of cash acquired	(31,576)
Capital expenditures, including internal-use software and website development	(23,598)	(13,249)
Purchases of marketable securities	(346,593)
Sales of marketable securities	68,053
Maturities of marketable securities	76,929
Proceeds from Expedia, Inc. related to Spin-Off		7,028
Other, net	350
Net cash used in investing activities	(256,435)	(6,221)
Financing activities:
Repurchase of common stock	(34,115)
Proceeds from credit facilities	6,701	7,627
Payments on credit facilities	(14,728)	(10,000)
Principal payments on long-term debt	(20,000)	(10,000)
Proceeds from exercise of stock options and warrants	19,847	225,769
Payment of minimum withholding taxes on net share settlements of equity awards	(5,534)	(3,035)
Excess tax benefits from stock-based compensation	5,242	2,011
Net cash (used) provided by financing activities	(42,587)	212,372
Effect of exchange rate changes on cash and cash equivalents	(1,722)	(2,919)
Net (decrease) increase in cash and cash equivalents	(167,457)	294,709
Cash and cash equivalents at beginning of year	367,515	183,532
Cash and cash equivalents at end of period	$ 200,058	$ 478,241