Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities:
Net income (loss)	$ 65,135	$ (27,833)	$ (4,334)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	50,688	36,753	35,060
Deferred tax (benefit) provision	(3,370)	29,174	(7,262)
Stock-based compensation expense	11,612	11,233	16,989
Provision for doubtful accounts and sales credits	7,008	5,488	7,698
Loss (gain) on sale of property and equipment		23	(184)
Reversal of pre-acquisition accrued contingency			(609)
Amortization of bond premium			55
Amortization of deferred interest	31	68	152
Deferred compensation	200		300
Stock-based compensation windfall tax benefit		(1,714)	(673)
Gain on sale of subsidiary	(47,321)
Amortization of debt issuance costs	333
Change in contingent consideration	(2,000)
Change in fair value of warrant	(1,000)
Realized gain on securities	(409)	(582)	(1,393)
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(17,157)	(12,059)	(6,342)
Prepaid expenses and other current assets	(3,983)	(9,627)	3,725
Accounts payable and accrued expenses	(609)	(1,403)	3,025
Deferred revenue	2,850	7	14
Other liabilities - long-term	1,966	(1)	(642)
Deferred rent	30	195	145
Other assets - long-term	922	(10,574)	(257)
Net cash provided by operating activities	64,926	19,148	45,467
Investing activities:
Capital expenditures	(9,555)	(10,801)	(5,360)
Restricted cash			142
Sale of investments	2,935	2,519	44,569
Capitalized software and website development costs	(20,086)	(16,899)	(13,021)
Proceeds from sale of property and equipment		1	109
Payment for cost investment	(7,500)
Payment for acquisition of business and intangible assets, net of acquired cash	(151,962)	(3,028)	(34,722)
Net cash used in investing activities	(186,168)	(28,208)	(8,283)
Financing activities:
Principal payments on capital lease obligations	(472)	(513)	(414)
Proceeds from the exercise of employee stock options	10,101	2,270	2,202
Proceeds from employee stock purchase plan	669	697	875
Purchases of treasury stock	(484)	(643)	(379)
Payment for debt issuance costs	(1,908)
Principal payments on notes payable			(848)
Stock-based compensation windfall tax benefit		1,714	673
Net cash provided by financing activities	7,906	3,525	2,109
Net (decrease) increase in cash and cash equivalents	(113,336)	(5,535)	39,293
Effect of exchange rate changes on cash and cash equivalents	(518)	589	2,760
Cash and cash equivalents, beginning of year	192,563	197,509	155,456
Cash and cash equivalents, end of year	78,709	192,563	197,509
Supplemental disclosure:
Income taxes	6,100	6,776	4,961
Interest	279	57	60
Non-cash investing and financing activities:
Accrued capitalized hardware, software and fixed assets	2,456	2,872	2,515
Assets acquired under capital leases	39	289	307
Capitalized stock-based compensation	100	77	133
Deferred compensation reversal to equity	200		300
Asset sale through note receivable			500
eCarList [Member]
Non-cash investing and financing activities:
Non-cash consideration issued for acquisition or investment	12,956
TrueCar [Member]
Non-cash investing and financing activities:
Non-cash consideration issued for acquisition or investment	$ 86,100