Guarantor Subsidiaries (Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	$ 12,671	$ 82,072
Net cash provided by operating activities - discontinued operations	3,982	9,003
Total cash (used in)/provided by operating activities	16,653	91,075
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(13,427)	(18,050)
Purchases of capitalized data and other intangible assets	(7,185)	(9,489)
Cash paid for acquisitions, net of cash acquired	(665,758)	(7,027)
Purchases of investments	0	(2,351)
Change in restricted cash	(580)	(40)
Net cash used in investing activities - continuing operations	(686,950)	(34,694)
Net cash used in investing activities - discontinued operations	(6)	(87)
Total cash used in investing activities	(686,956)	(34,781)
Cash Received From Sale Of Subsidiary	0	2,263
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	689,641	0
Payments of Debt Issuance Costs	(14,042)	0
Repayments of long-term debt	(5,154)	(4,400)
Share repurchased and retired	(6,850)	(75,676)
Proceeds from issuance of stock related to stock options and employee benefit plans	2,730	4,621
Minimum tax withholding paid on behalf of employees for restricted stock units	(14,314)	(6,437)
Tax benefit related to stock options	5,942	2,321
Net cash used in financing activities - continuing operations	657,953	(79,571)
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	657,953	(79,571)
Effect of exchange rate on cash	482	(26)
Net (decrease)/increase in cash and cash equivalents	(11,868)	(23,303)
Cash and cash equivalents at beginning of period	134,741	151,986
Less: Change in cash and cash equivalents - discontinued operations	3,976	8,916
Plus: Cash swept from discontinued operations	4,009	8,866
Cash and cash equivalents at end of period	122,906	128,633
Parent [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	(21,816)	32,508
Net cash provided by operating activities - discontinued operations	0	0
Total cash (used in)/provided by operating activities	(21,816)	32,508
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(824)	(871)
Purchases of capitalized data and other intangible assets	0	(390)
Cash paid for acquisitions, net of cash acquired	0	0
Purchases of investments		0
Change in restricted cash	(700)	(4)
Net cash used in investing activities - continuing operations	(1,524)	(1,265)
Net cash used in investing activities - discontinued operations	0	0
Total cash used in investing activities	(1,524)	(1,265)
Cash Received From Sale Of Subsidiary		0
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	689,641
Payments of Debt Issuance Costs	(14,042)
Repayments of long-term debt	(266)	(4,375)
Share repurchased and retired	(6,850)	(75,676)
Proceeds from issuance of stock related to stock options and employee benefit plans	2,730	4,621
Minimum tax withholding paid on behalf of employees for restricted stock units	(14,314)	(6,437)
Tax benefit related to stock options	5,942	2,321
Intercompany Payments	(665,666)	0
Other	0	47,458
Net cash used in financing activities - continuing operations	(2,825)	(32,088)
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	(2,825)	(32,088)
Effect of exchange rate on cash	0	0
Net (decrease)/increase in cash and cash equivalents	(26,165)	(845)
Cash and cash equivalents at beginning of period	104,632	111,305
Less: Change in cash and cash equivalents - discontinued operations	0	0
Plus: Cash swept from discontinued operations	4,009	(2,408)
Cash and cash equivalents at end of period	82,476	108,052
Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	29,798	54,908
Net cash provided by operating activities - discontinued operations	3,982	9,003
Total cash (used in)/provided by operating activities	33,780	63,911
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(9,557)	(15,025)
Purchases of capitalized data and other intangible assets	(6,841)	(8,051)
Cash paid for acquisitions, net of cash acquired	(636,640)	(7,027)
Purchases of investments		(2,351)
Change in restricted cash	185	1
Net cash used in investing activities - continuing operations	(652,853)	(30,190)
Net cash used in investing activities - discontinued operations	(6)	(87)
Total cash used in investing activities	(652,859)	(30,277)
Cash Received From Sale Of Subsidiary		2,263
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	0
Payments of Debt Issuance Costs	0
Repayments of long-term debt	(4,888)	(25)
Share repurchased and retired	0	0
Proceeds from issuance of stock related to stock options and employee benefit plans	0	0
Minimum tax withholding paid on behalf of employees for restricted stock units	0	0
Tax benefit related to stock options	0	0
Intercompany Payments		(41,854)
Other	636,737	0
Net cash used in financing activities - continuing operations	631,849	(41,879)
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	631,849	(41,879)
Effect of exchange rate on cash	0	0
Net (decrease)/increase in cash and cash equivalents	12,770	(8,245)
Cash and cash equivalents at beginning of period	0	5,889
Less: Change in cash and cash equivalents - discontinued operations	3,976	(8,916)
Plus: Cash swept from discontinued operations	0	11,274
Cash and cash equivalents at end of period	8,794	2
Non-Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	4,689	(5,344)
Net cash provided by operating activities - discontinued operations	0	0
Total cash (used in)/provided by operating activities	4,689	(5,344)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(3,046)	(2,154)
Purchases of capitalized data and other intangible assets	(344)	(1,048)
Cash paid for acquisitions, net of cash acquired	(29,118)	0
Purchases of investments		0
Change in restricted cash	(65)	(37)
Net cash used in investing activities - continuing operations	(32,573)	(3,239)
Net cash used in investing activities - discontinued operations	0	0
Total cash used in investing activities	(32,573)	(3,239)
Cash Received From Sale Of Subsidiary		0
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	0
Payments of Debt Issuance Costs	0
Repayments of long-term debt	0	0
Share repurchased and retired	0	0
Proceeds from issuance of stock related to stock options and employee benefit plans	0	0
Minimum tax withholding paid on behalf of employees for restricted stock units	0	0
Tax benefit related to stock options	0	0
Intercompany Payments		(5,604)
Other	28,929	0
Net cash used in financing activities - continuing operations	28,929	(5,604)
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	28,929	(5,604)
Effect of exchange rate on cash	482	(26)
Net (decrease)/increase in cash and cash equivalents	1,527	(14,213)
Cash and cash equivalents at beginning of period	30,109	34,792
Less: Change in cash and cash equivalents - discontinued operations	0	0
Plus: Cash swept from discontinued operations	0	0
Cash and cash equivalents at end of period	31,636	20,579
Consolidation, Eliminations [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	0	0
Net cash provided by operating activities - discontinued operations	0	0
Total cash (used in)/provided by operating activities	0	0
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	0	0
Purchases of capitalized data and other intangible assets	0	0
Cash paid for acquisitions, net of cash acquired	0	0
Purchases of investments		0
Change in restricted cash	0	0
Net cash used in investing activities - continuing operations	0	0
Net cash used in investing activities - discontinued operations	0	0
Total cash used in investing activities	0	0
Cash Received From Sale Of Subsidiary		0
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	0
Payments of Debt Issuance Costs	0
Repayments of long-term debt	0	0
Share repurchased and retired	0	0
Proceeds from issuance of stock related to stock options and employee benefit plans	0	0
Minimum tax withholding paid on behalf of employees for restricted stock units	0	0
Tax benefit related to stock options	0	0
Intercompany Payments	665,666	47,458
Other	(665,666)	(47,458)
Net cash used in financing activities - continuing operations	0	0
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	0	0
Effect of exchange rate on cash	0	0
Net (decrease)/increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Less: Change in cash and cash equivalents - discontinued operations	0	0
Plus: Cash swept from discontinued operations	0	0
Cash and cash equivalents at end of period	0	0
Total [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	12,671	82,072
Net cash provided by operating activities - discontinued operations	3,982	9,003
Total cash (used in)/provided by operating activities	16,653	91,075
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(13,427)	(18,050)
Purchases of capitalized data and other intangible assets	(7,185)	(9,489)
Cash paid for acquisitions, net of cash acquired	(665,758)	(7,027)
Purchases of investments		(2,351)
Change in restricted cash	(580)	(40)
Net cash used in investing activities - continuing operations	(686,950)	(34,694)
Net cash used in investing activities - discontinued operations	(6)	(87)
Total cash used in investing activities	(686,956)	(34,781)
Cash Received From Sale Of Subsidiary		2,263
Net Cash Provided by (Used in) Financing Activities [Abstract]
Repayments of long-term debt	(5,154)	(4,400)
Share repurchased and retired	(6,850)	(75,676)
Proceeds from issuance of stock related to stock options and employee benefit plans	2,730	4,621
Minimum tax withholding paid on behalf of employees for restricted stock units	(14,314)	(6,437)
Tax benefit related to stock options	5,942	2,321
Intercompany Payments	0	0
Other	0	0
Net cash used in financing activities - continuing operations	657,953	(79,571)
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	657,953	(79,571)
Effect of exchange rate on cash	482
Net (decrease)/increase in cash and cash equivalents	(11,868)	(23,303)
Cash and cash equivalents at beginning of period	134,741	151,986
Less: Change in cash and cash equivalents - discontinued operations	3,976	8,916
Plus: Cash swept from discontinued operations	4,009
Cash and cash equivalents at end of period	$ 122,906	$ 128,633