Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Operating activities:
Net income	$ 19,051	$ 11,809	$ 44,579	$ 24,294
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	3,341	2,751	9,793	8,355
Amortization of content database costs	2,377	1,900	6,792	5,564
Amortization of acquired intangible assets	4,304	3,791	12,871	11,149
Amortization of deferred financing costs	66	1,539	204	2,368
Deferred income taxes	156	3,627	(2,833)	990
Stock-based compensation expense	2,942	1,275	6,868	3,541
Changes in operating assets and liabilities:
Accounts receivable	(785)	561	523	1,496
Restricted cash	206	(90)	742	(260)
Other assets	(2,066)	(1,343)	(2,299)	627
Income tax receivable	1,947	(2,439)	(5,321)	(895)
Accounts payable and other liabilities	468	10,216	23,616	18,404
Excess tax benefits from stock-based compensation	(4,061)	(4,071)	(24,510)	(7,641)
Deferred revenues	(1,774)	475	23,132	19,563
Net cash provided by operating activities	26,172	30,001	94,157	87,555
Investing activities:
Capitalization of content database costs	(4,673)	(3,393)	(14,624)	(8,534)
Purchases of property and equipment	(4,573)	(4,269)	(8,991)	(7,897)
Acquisitions of businesses, net of cash acquired		(7,781)		(7,781)
Purchases of short-term investments				(7,193)
Proceeds from sale and maturity of short-term investments		14,527		24,564
Net cash used in investing activities	(9,246)	(916)	(23,615)	(6,841)
Financing activities:
Proceeds from exercise of stock options	2,045	4,442	12,067	9,514
Taxes paid related to net share settlement of stock-based awards	(232)		(747)
Principal payments on debt		(76,230)		(100,025)
Deferred financing costs from issuance of credit facility		(733)		(733)
Excess tax benefits from stock-based compensation	4,061	4,071	24,510	7,641
Repurchases of common stock	(46,905)		(125,000)
Net cash used in financing activities	(41,031)	(68,450)	(89,170)	(83,603)
Effect of changes in foreign currency exchange rates on cash and cash equivalents	(18)	33	5	33
Net decrease in cash and cash equivalents	(24,123)	(39,332)	(18,623)	(2,856)
Cash and cash equivalents at beginning of period	71,019	103,417	65,519	66,941
Cash and cash equivalents at end of period	46,896	64,085	46,896	64,085
Supplemental disclosures of cash flow information:
Cash paid for interest	107	1,051	333	2,528
Cash paid for income taxes	126	164	3,683	6,345
Supplemental disclosures of noncash investing and financing activities:
Capitalization of stock-based compensation	$ 11	$ 3	$ 29	$ 6