Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Net income	$ 185,169	$ 160,871
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	20,834	14,033
Stock-based compensation	35,470	19,923
Amortization of intangible assets	4,182	4,909
Amortization of deferred financing costs	594	683
Amortization of discounts and premiums on marketable securities, net	3,821
Deferred tax (benefit) expense	(452)	413
Excess tax benefits from stock-based compensation	(8,807)	(2,189)
Provision (recovery) for doubtful accounts	1,378	(1,584)
Foreign currency transaction (gains) losses, net	29	1,779
Other, net	1,600	21
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	(28,625)	(32,461)
Related parties	(9,898)	(25,500)
Taxes receivable	14,056	(4,006)
Prepaid expenses and other assets	(3,222)	(1,885)
Accounts payable	(3,277)	3,641
Deferred merchant payables	12,769	(1,021)
Taxes payable	21,205	(528)
Accrued expenses and other liabilities	22,492	20,447
Deferred revenue	9,005	10,383
Net cash provided by operating activities	278,323	167,929
Investing activities:
Acquisitions, net of cash acquired	(31,516)
Capital expenditures, including internal-use software and website development	(39,318)	(20,587)
Purchases of marketable securities	(375,368)
Sales of marketable securities	123,647
Maturities of marketable securities	105,739
Proceeds from Expedia, Inc. related to Spin-Off		7,028
Other, net	350
Net cash used in investing activities	(216,466)	(13,559)
Financing activities:
Repurchase of common stock	(137,565)
Proceeds from credit facilities	8,080	12,798
Payments on credit facilities	(14,728)	(10,000)
Principal payments on long-term debt	(30,000)	(15,000)
Proceeds from exercise of stock options and warrants	21,058	226,251
Payment of minimum withholding taxes on net share settlements of equity awards	(9,878)	(3,689)
Excess tax benefits from stock-based compensation	8,807	2,189
Net cash (used) provided by financing activities	(154,226)	212,549
Effect of exchange rate changes on cash and cash equivalents	1,212	(2,079)
Net (decrease) increase in cash and cash equivalents	(91,157)	364,840
Cash and cash equivalents at beginning of year	367,515	183,532
Cash and cash equivalents at end of period	276,358	548,372
Marketable securities sold during the period but settled after period end	$ 40,406