Guarantor Subsidiaries (Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	$ 167,962	$ 183,067
Net cash provided by operating activities - discontinued operations	(1,288)	9,490
Total cash (used in)/provided by operating activities	166,674	192,557
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(34,672)	(24,939)
Purchases of capitalized data and other intangible assets	(18,928)	(15,397)
Cash paid for acquisitions, net of cash acquired	(6,852)
Cash Received From Sale Of Subsidiary	800	0
Purchases of investments	(2,351)	0
Proceeds from sale of property and equipment	0	1,832
Change in restricted cash	2,093	123
Net cash used in investing activities - continuing operations	(59,910)	(38,381)
Net cash used in investing activities - discontinued operations	0	(4,745)
Total cash used in investing activities	(59,910)	(43,126)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	551	0
Repayments of long-term debt	(4,423)	(113,825)
Share repurchased and retired	(75,676)	(28,744)
Proceeds from issuance of stock related to stock options and employee benefit plans	7,119	768
Minimum tax withholding paid on behalf of employees for restricted stock units	(6,680)	(2,577)
Distribution to noncontrolling interests	0	(10)
Tax benefit related to stock options	2,652	109
Net cash used in financing activities - continuing operations	(76,457)	(144,279)
Net cash provided by financing activities - discontinued operations	0	2
Total cash (used in)/provided by financing activities	(76,457)	(144,277)
Effect of Exchange Rate on Cash	(2,574)	0
Net (decrease)/increase in cash and cash equivalents	27,733	5,154
Cash and cash equivalents at beginning of period	148,858	259,266
Less: Change in cash and cash equivalents - discontinued operations	(1,288)	4,747
Plus: Cash swept from discontinued operations	(1,288)	0
Cash and cash equivalents at end of period	176,591	259,673
Parent [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	(11,627)	3,462
Net cash provided by operating activities - discontinued operations	0	0
Total cash (used in)/provided by operating activities	(11,627)	3,462
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(2,698)	(244)
Purchases of capitalized data and other intangible assets	(376)	0
Cash paid for acquisitions, net of cash acquired	0
Purchases of investments	0
Proceeds from Divestiture of Businesses	0
Proceeds from sale of property and equipment		0
Change in restricted cash	(4)	0
Net cash used in investing activities - continuing operations	(3,078)	(244)
Net cash used in investing activities - discontinued operations	0	0
Total cash used in investing activities	(3,078)	(244)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	0
Repayments of long-term debt	(4,375)	(103,018)
Share repurchased and retired	(75,676)	(28,744)
Proceeds from issuance of stock related to stock options and employee benefit plans	7,119	768
Minimum tax withholding paid on behalf of employees for restricted stock units	(6,680)	(2,577)
Distribution to noncontrolling interests		0
Tax benefit related to stock options	2,326	109
Intercompany Payments	0	(5,963)
Other	129,747	152,437
Net cash used in financing activities - continuing operations	52,461	13,012
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	52,461	13,012
Effect of Exchange Rate on Cash	0
Net (decrease)/increase in cash and cash equivalents	37,756	16,230
Cash and cash equivalents at beginning of period	111,305	229,871
Less: Change in cash and cash equivalents - discontinued operations	0	0
Plus: Cash swept from discontinued operations	(1,286)
Cash and cash equivalents at end of period	147,775	246,101
Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	173,567	182,119
Net cash provided by operating activities - discontinued operations	(1,288)	9,490
Total cash (used in)/provided by operating activities	172,279	191,609
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(27,999)	(18,146)
Purchases of capitalized data and other intangible assets	(16,432)	(14,043)
Cash paid for acquisitions, net of cash acquired	(6,852)
Purchases of investments	(2,351)
Proceeds from Divestiture of Businesses	800
Proceeds from sale of property and equipment		1,832
Change in restricted cash	0	(184)
Net cash used in investing activities - continuing operations	(52,834)	(30,541)
Net cash used in investing activities - discontinued operations	0	(4,745)
Total cash used in investing activities	(52,834)	(35,286)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	551
Repayments of long-term debt	(48)	(10,726)
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
Distribution to noncontrolling interests		(10)
Tax benefit related to stock options	326	0
Intercompany Payments	(121,761)	(152,437)
Other	0	0
Net cash used in financing activities - continuing operations	(120,932)	(163,163)
Net cash provided by financing activities - discontinued operations	0	2
Total cash (used in)/provided by financing activities	(120,932)	(163,161)
Effect of Exchange Rate on Cash	0
Net (decrease)/increase in cash and cash equivalents	(1,487)	(6,838)
Cash and cash equivalents at beginning of period	1,812	9,106
Less: Change in cash and cash equivalents - discontinued operations	(1,288)	4,747
Plus: Cash swept from discontinued operations	(2)
Cash and cash equivalents at end of period	1,611	(2,479)
Non-Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations	6,022	(2,514)
Net cash provided by operating activities - discontinued operations	0	0
Total cash (used in)/provided by operating activities	6,022	(2,514)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(3,975)	(6,549)
Purchases of capitalized data and other intangible assets	(2,120)	(1,354)
Cash paid for acquisitions, net of cash acquired	0
Purchases of investments	0
Proceeds from Divestiture of Businesses	0
Proceeds from sale of property and equipment		0
Change in restricted cash	2,097	307
Net cash used in investing activities - continuing operations	(3,998)	(7,596)
Net cash used in investing activities - discontinued operations	0	0
Total cash used in investing activities	(3,998)	(7,596)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	0
Repayments of long-term debt	0	(81)
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
Distribution to noncontrolling interests		0
Tax benefit related to stock options	0	0
Intercompany Payments	(7,986)	0
Other	0	5,963
Net cash used in financing activities - continuing operations	(7,986)	5,872
Net cash provided by financing activities - discontinued operations	0	0
Total cash (used in)/provided by financing activities	(7,986)	5,872
Effect of Exchange Rate on Cash	(2,574)
Net (decrease)/increase in cash and cash equivalents	(8,536)	(4,238)
Cash and cash equivalents at beginning of period	35,741	20,289
Less: Change in cash and cash equivalents - discontinued operations	0	0
Plus: Cash swept from discontinued operations	0
Cash and cash equivalents at end of period	27,205	16,051
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
Purchases of investments	0
Proceeds from Divestiture of Businesses	0
Proceeds from sale of property and equipment		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
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt	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
Distribution to noncontrolling interests		0
Tax benefit related to stock options	0	0
Intercompany Payments	129,747	158,400
Other	(129,747)	(158,400)
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
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
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	167,962	183,067
Net cash provided by operating activities - discontinued operations	(1,288)	9,490
Total cash (used in)/provided by operating activities	166,674	192,557
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment	(34,672)	(24,939)
Purchases of capitalized data and other intangible assets	(18,928)	(15,397)
Cash paid for acquisitions, net of cash acquired	(6,852)
Purchases of investments	(2,351)
Proceeds from Divestiture of Businesses	800
Proceeds from sale of property and equipment		1,832
Change in restricted cash	2,093	123
Net cash used in investing activities - continuing operations	(59,910)	(38,381)
Net cash used in investing activities - discontinued operations	0	(4,745)
Total cash used in investing activities	(59,910)	(43,126)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Repayments of long-term debt	(4,423)	(113,825)
Share repurchased and retired	(75,676)	(28,744)
Proceeds from issuance of stock related to stock options and employee benefit plans	7,119	768
Minimum tax withholding paid on behalf of employees for restricted stock units	(6,680)	(2,577)
Distribution to noncontrolling interests		(10)
Tax benefit related to stock options	2,652	109
Intercompany Payments	0	0
Other	0	0
Net cash used in financing activities - continuing operations	(76,457)	(144,279)
Net cash provided by financing activities - discontinued operations	0	2
Total cash (used in)/provided by financing activities	(76,457)	(144,277)
Effect of Exchange Rate on Cash	(2,574)
Net (decrease)/increase in cash and cash equivalents	27,733	5,154
Cash and cash equivalents at beginning of period	148,858	259,266
Less: Change in cash and cash equivalents - discontinued operations	(1,288)	4,747
Plus: Cash swept from discontinued operations	(1,288)
Cash and cash equivalents at end of period	$ 176,591	$ 259,673