Guarantor Subsidiaries (Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net cash (used in)/provided by operating activities - continuing operations	$ 362,299	$ 171,592	$ 164,145
Net cash provided by/(used in) operating activities - discontinued operations	820	(10,655)	42,049
Total cash (used in)/provided by operating activities	363,119	160,937	206,194
Cash flows from investing activities:
Purchases of property and equipment	(52,600)	(45,215)	(52,610)
Purchases of capitalized data and other intangible assets	(31,880)	(27,009)	(24,814)
Cash paid for acquisitions, net of cash acquired	(78,354)	(214,215)	(9,228)
Cash received from sale of subsidiary, net	10,000	28,054	265,000
Purchases of investments	0	(26,898)	(27,284)
Proceeds from maturities of debt securities	0	0	371
Proceeds from sale of property and equipment	1,882	25,042	0
Proceeds from sale of investments	8,000	74,621	26,386
Cash received from sale of subsidiary, net		28,054
Issuance of notes receivable, net			(12,754)
Change in restricted cash	86	2,091	(21,095)
Net cash used in investing activities - continuing operations	(142,866)	(183,529)	143,972
Net cash used in investing activities - discontinued operations	(4,066)	(4,497)	(82,729)
Total cash used in by investing activities	(146,932)	(188,026)	61,243
Cash flows from financing activities:
Purchases of redeemable noncontrolling interests	0	(72,000)	(385,847)
Proceeds from long-term debt	50,000	858,154	843,524
Debt issuance costs	0	(22,810)	(14,776)
Repayments of long-term debt	(166,715)	(733,407)	(713,643)
Shares repurchased and retired	(226,629)	(176,512)	(30,171)
Proceeds from issuance of stock related to stock options and employee benefit plans	13,497	3,087	11,674
Minimum tax withholding paid on behalf of employees for restricted stock units	(3,466)	(2,023)	(4,677)
Distribution to noncontrolling interests	(10)	(4,835)	(27,800)
Cash dividends	0	0	(22,657)
Tax benefit related to stock options	947	363	3,423
Intercompany Payments	0	0	0
Intercompany loan proceeds	0	0	0
Net cash (used in)/provided by financing activities - continuing operations	(332,376)	(149,983)	(340,950)
Net cash used in financing activities - discontinued operations	(71)	71	29,087
Total cash (used in)/provided by financing activities	(332,447)	(149,912)	(311,863)
Net (decrease)/increase in cash and cash equivalents	(116,260)	(177,001)	(44,426)
Cash and cash equivalents at beginning of year	259,266	426,212	459,519
Less: Change in cash and cash equivalents of discontinued operations	(3,317)	(15,081)	(11,593)
Plus: Cash swept from/(to) discontinued operations	2,535	(5,026)	(474)
Cash and cash equivalents at end of year	148,858	259,266	426,212
Parent [Member]
Cash flows from operating activities:
Net cash (used in)/provided by operating activities - continuing operations	(79,525)	(12,523)	(65,230)
Net cash provided by/(used in) operating activities - discontinued operations	0	0	0
Total cash (used in)/provided by operating activities	(79,525)	(12,523)	(65,230)
Cash flows from investing activities:
Purchases of property and equipment	(3,195)	(785)	(3,347)
Purchases of capitalized data and other intangible assets	0	0	0
Cash paid for acquisitions, net of cash acquired	0	(219,317)	0
Cash received from sale of subsidiary, net	0		0
Purchases of investments		725	(18,764)
Proceeds from maturities of debt securities			0
Proceeds from sale of property and equipment	0	0
Proceeds from sale of investments	0	0	0
Cash received from sale of subsidiary, net		0
Issuance of notes receivable, net			0
Change in restricted cash	(1)	2,675	(20,973)
Net cash used in investing activities - continuing operations	(3,196)	(216,702)	(43,084)
Net cash used in investing activities - discontinued operations	0	0	0
Total cash used in by investing activities	(3,196)	(216,702)	(43,084)
Cash flows from financing activities:
Purchases of redeemable noncontrolling interests		0	0
Proceeds from long-term debt	50,000	750,000	843,524
Debt issuance costs	0	(22,810)	(14,776)
Repayments of long-term debt	(103,368)	(575,787)	(691,258)
Shares repurchased and retired	(226,629)	(176,512)	(30,171)
Proceeds from issuance of stock related to stock options and employee benefit plans	13,497	3,087	11,674
Minimum tax withholding paid on behalf of employees for restricted stock units	(3,466)	(2,023)	(4,677)
Distribution to noncontrolling interests	0	0	0
Cash dividends			(22,657)
Tax benefit related to stock options	947	363	3,423
Intercompany Payments	(65,227)	0	(35,721)
Intercompany loan proceeds	295,866	131,830	240,389
Net cash (used in)/provided by financing activities - continuing operations	(38,380)	108,148	299,750
Net cash used in financing activities - discontinued operations	0	0	0
Total cash (used in)/provided by financing activities	(38,380)	108,148	299,750
Net (decrease)/increase in cash and cash equivalents	(121,101)	(121,077)	191,436
Cash and cash equivalents at beginning of year	229,871	355,974	165,012
Less: Change in cash and cash equivalents of discontinued operations	0	0	0
Plus: Cash swept from/(to) discontinued operations	2,535	(5,026)	(474)
Cash and cash equivalents at end of year	111,305	229,871	355,974
Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in)/provided by operating activities - continuing operations	424,683	177,100	220,002
Net cash provided by/(used in) operating activities - discontinued operations	820	(10,655)	18,598
Total cash (used in)/provided by operating activities	425,503	166,445	238,600
Cash flows from investing activities:
Purchases of property and equipment	(37,952)	(38,503)	(48,114)
Purchases of capitalized data and other intangible assets	(28,483)	(26,447)	(24,814)
Cash paid for acquisitions, net of cash acquired	(78,354)	4,220	(11,401)
Cash received from sale of subsidiary, net	10,000		0
Purchases of investments		(27,623)	(8,520)
Proceeds from maturities of debt securities			371
Proceeds from sale of property and equipment	1,882	25,042
Proceeds from sale of investments	8,000	74,621	26,386
Cash received from sale of subsidiary, net		5,300
Issuance of notes receivable, net			(12,754)
Change in restricted cash	(184)	(1)	(122)
Net cash used in investing activities - continuing operations	(125,091)	16,609	(78,968)
Net cash used in investing activities - discontinued operations	(4,066)	(4,497)	(12,193)
Total cash used in by investing activities	(129,157)	12,112	(91,161)
Cash flows from financing activities:
Purchases of redeemable noncontrolling interests		(72,000)	(385,847)
Proceeds from long-term debt	0	54,544	0
Debt issuance costs	0	0	0
Repayments of long-term debt	(11,020)	(107,094)	(22,385)
Shares repurchased and retired	0	0	0
Proceeds from issuance of stock related to stock options and employee benefit plans	0	0	0
Minimum tax withholding paid on behalf of employees for restricted stock units	0	0	0
Distribution to noncontrolling interests	0	(4,290)	(27,800)
Cash dividends			0
Tax benefit related to stock options	0	0	0
Intercompany Payments	(295,866)	(78,776)	0
Intercompany loan proceeds	0	0	35,721
Net cash (used in)/provided by financing activities - continuing operations	(306,886)	(207,616)	(400,311)
Net cash used in financing activities - discontinued operations	(71)	71	0
Total cash (used in)/provided by financing activities	(306,957)	(207,545)	(400,311)
Net (decrease)/increase in cash and cash equivalents	(10,611)	(28,988)	(252,872)
Cash and cash equivalents at beginning of year	9,106	23,013	282,290
Less: Change in cash and cash equivalents of discontinued operations	(3,317)	(15,081)	6,405
Plus: Cash swept from/(to) discontinued operations	0
Cash and cash equivalents at end of year	1,812	9,106	23,013
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash (used in)/provided by operating activities - continuing operations	17,141	7,015	9,373
Net cash provided by/(used in) operating activities - discontinued operations	0	0	23,451
Total cash (used in)/provided by operating activities	17,141	7,015	32,824
Cash flows from investing activities:
Purchases of property and equipment	(11,453)	(5,927)	(1,149)
Purchases of capitalized data and other intangible assets	(3,397)	(562)	0
Cash paid for acquisitions, net of cash acquired	0	882	2,173
Cash received from sale of subsidiary, net	0		265,000
Purchases of investments		0	0
Proceeds from maturities of debt securities			0
Proceeds from sale of property and equipment	0	0
Proceeds from sale of investments	0	0	0
Cash received from sale of subsidiary, net		22,754
Issuance of notes receivable, net			0
Change in restricted cash	271	(583)	0
Net cash used in investing activities - continuing operations	(14,579)	16,564	266,024
Net cash used in investing activities - discontinued operations	0	0	(70,536)
Total cash used in by investing activities	(14,579)	16,564	195,488
Cash flows from financing activities:
Purchases of redeemable noncontrolling interests		0	0
Proceeds from long-term debt	0	53,610	0
Debt issuance costs	0	0	0
Repayments of long-term debt	(52,327)	(50,526)	0
Shares repurchased and retired	0	0	0
Proceeds from issuance of stock related to stock options and employee benefit plans	0	0	0
Minimum tax withholding paid on behalf of employees for restricted stock units	0	0	0
Distribution to noncontrolling interests	(10)	(545)	0
Cash dividends			0
Tax benefit related to stock options	0	0	0
Intercompany Payments	0	(53,054)	(240,389)
Intercompany loan proceeds	65,227	0	0
Net cash (used in)/provided by financing activities - continuing operations	12,890	(50,515)	(240,389)
Net cash used in financing activities - discontinued operations	0	0	29,087
Total cash (used in)/provided by financing activities	12,890	(50,515)	(211,302)
Net (decrease)/increase in cash and cash equivalents	15,452	(26,936)	17,010
Cash and cash equivalents at beginning of year	20,289	47,225	12,217
Less: Change in cash and cash equivalents of discontinued operations	0	0	(17,998)
Plus: Cash swept from/(to) discontinued operations	0	0
Cash and cash equivalents at end of year	35,741	20,289	47,225
Consolidating/Eliminating Adjustments [Member]
Cash flows from operating activities:
Net cash (used in)/provided by operating activities - continuing operations	0	0	0
Net cash provided by/(used in) operating activities - discontinued operations	0	0	0
Total cash (used in)/provided by operating activities	0	0	0
Cash flows from investing activities:
Purchases of property and equipment	0	0	0
Purchases of capitalized data and other intangible assets	0	0	0
Cash paid for acquisitions, net of cash acquired	0	0	0
Cash received from sale of subsidiary, net	0		0
Purchases of investments		0	0
Proceeds from maturities of debt securities			0
Proceeds from sale of property and equipment	0	0
Proceeds from sale of investments	0	0	0
Cash received from sale of subsidiary, net		0
Issuance of notes receivable, net			0
Change in restricted cash	0	0	0
Net cash used in investing activities - continuing operations	0	0	0
Net cash used in investing activities - discontinued operations	0	0	0
Total cash used in by investing activities	0	0	0
Cash flows from financing activities:
Purchases of redeemable noncontrolling interests		0	0
Proceeds from long-term debt	0	0	0
Debt issuance costs	0	0	0
Repayments of long-term debt	0	0	0
Shares repurchased and retired	0	0	0
Proceeds from issuance of stock related to stock options and employee benefit plans	0	0	0
Minimum tax withholding paid on behalf of employees for restricted stock units	0	0	0
Distribution to noncontrolling interests	0	0	0
Cash dividends			0
Tax benefit related to stock options	0	0	0
Intercompany Payments	361,093	131,830	276,110
Intercompany loan proceeds	(361,093)	(131,830)	(276,110)
Net cash (used in)/provided by financing activities - continuing operations	0	0	0
Net cash used in financing activities - discontinued operations	0	0	0
Total cash (used in)/provided by financing activities	0	0	0
Net (decrease)/increase in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Less: Change in cash and cash equivalents of discontinued operations	0	0	0
Plus: Cash swept from/(to) discontinued operations	0	0	0
Cash and cash equivalents at end of year	$ 0	$ 0	$ 0