Consolidating Financial Information Consolidating Statement of Operations (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Consolidating Statement of Operations [Line Items]
Revenues	$ 612,401	$ 567,339	$ 1,176,092	$ 1,064,962
Cost of revenues	421,318	393,283	800,899	733,842
Gross profit	191,083	174,056	375,193	331,120
Operating expenses
Sales and marketing	48,845	40,974	93,493	82,511
Product development	40,931	33,022	81,376	66,062
General and administrative	35,118	33,285	68,449	66,342
Amortization of intangible assets	16,197	16,766	31,794	34,577
Restructuring	1,907	0	1,907	0
Total operating expenses	142,998	124,047	277,019	249,492
Operating income	48,085	50,009	98,174	81,628
Other income and (expense)
Interest income	168	111	476	278
Interest expense	(11,420)	(13,965)	(23,534)	(28,888)
Other income (expense), net	(2,477)	(425)	(4,073)	(1,017)
Total other income (expense)	(13,729)	(14,279)	(27,131)	(29,627)
Income before income taxes	34,356	35,730	71,043	52,001
Income tax (provision) benefit	80	(10,419)	(9,487)	(1,440)
Equity in earnings of guarantor and non-guarantor subsidiaries, net	0	0	0	0
Net income	34,436	25,311	61,556	50,561
Parent [Member]
Consolidating Statement of Operations [Line Items]
Revenues	289,090	298,380	562,653	539,253
Cost of revenues	194,728	199,882	377,003	364,772
Gross profit	94,362	98,498	185,650	174,481
Operating expenses
Sales and marketing	18,195	15,706	35,210	31,273
Product development	26,673	21,051	51,864	42,229
General and administrative	13,529	13,467	26,474	27,250
Amortization of intangible assets	3,512	4,086	7,024	8,172
Restructuring	501		501
Total operating expenses	62,410	54,310	121,073	108,924
Operating income	31,952	44,188	64,577	65,557
Other income and (expense)
Interest income	57	116	14,902	475
Interest expense	(12,178)	(14,621)	(24,997)	(30,201)
Other income (expense), net	(1,436)	4,002	(2,603)	2,973
Total other income (expense)	(13,557)	(10,503)	(12,698)	(26,753)
Income before income taxes	18,395	33,685	51,879	38,804
Income tax (provision) benefit	(2,823)	(12,539)	(14,190)	(2,792)
Equity in earnings of guarantor and non-guarantor subsidiaries, net	18,864	4,165	23,867	14,549
Net income	34,436	25,311	61,556	50,561
Guarantor Subsidiary [Member]
Consolidating Statement of Operations [Line Items]
Revenues	0	0	0	0
Cost of revenues	0	0	0	0
Gross profit	0	0	0	0
Operating expenses
Sales and marketing	0	0	0	0
Product development	0	0	0	0
General and administrative	0	0	0	0
Amortization of intangible assets	0	0	0	0
Restructuring	0		0
Total operating expenses	0	0	0	0
Operating income	0	0	0	0
Other income and (expense)
Interest income	842	776	1,668	1,534
Interest expense	0	0	0	0
Other income (expense), net	0	0	0	0
Total other income (expense)	842	776	1,668	1,534
Income before income taxes	842	776	1,668	1,534
Income tax (provision) benefit	0	0	0	0
Equity in earnings of guarantor and non-guarantor subsidiaries, net	0	0	0	0
Net income	842	776	1,668	1,534
Combined Non-Guarantor Subsidiaries [Member]
Consolidating Statement of Operations [Line Items]
Revenues	345,332	283,082	653,623	551,911
Cost of revenues	248,611	207,524	464,080	395,272
Gross profit	96,721	75,558	189,543	156,639
Operating expenses
Sales and marketing	30,650	25,268	58,283	51,238
Product development	14,258	11,971	29,512	23,833
General and administrative	21,589	19,818	41,975	39,092
Amortization of intangible assets	12,685	12,680	24,770	26,405
Restructuring	1,406		1,406
Total operating expenses	80,588	69,737	155,946	140,568
Operating income	16,133	5,821	33,597	16,071
Other income and (expense)
Interest income	134	87	411	226
Interest expense	(107)	(212)	(15,042)	(644)
Other income (expense), net	(1,041)	(4,427)	(1,470)	(3,990)
Total other income (expense)	(1,014)	(4,552)	(16,101)	(4,408)
Income before income taxes	15,119	1,269	17,496	11,663
Income tax (provision) benefit	2,903	2,120	4,703	1,352
Equity in earnings of guarantor and non-guarantor subsidiaries, net	0	0	0	0
Net income	18,022	3,389	22,199	13,015
Eliminations [Member]
Consolidating Statement of Operations [Line Items]
Revenues	(22,021)	(14,123)	(40,184)	(26,202)
Cost of revenues	(22,021)	(14,123)	(40,184)	(26,202)
Gross profit	0	0	0	0
Operating expenses
Sales and marketing	0	0	0	0
Product development	0	0	0	0
General and administrative	0	0	0	0
Amortization of intangible assets	0	0	0	0
Restructuring	0		0
Total operating expenses	0	0	0	0
Operating income	0	0	0	0
Other income and (expense)
Interest income	(865)	(868)	(16,505)	(1,957)
Interest expense	865	868	16,505	1,957
Other income (expense), net	0	0	0	0
Total other income (expense)	0	0	0	0
Income before income taxes	0	0	0	0
Income tax (provision) benefit	0	0	0	0
Equity in earnings of guarantor and non-guarantor subsidiaries, net	(18,864)	(4,165)	(23,867)	(14,549)
Net income	$ (18,864)	$ (4,165)	$ (23,867)	$ (14,549)