Guarantor Subsidiaries (Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		$ 261,253	$ 210,743
Net cash provided by operating activities - discontinued operations		(7,584)	(2,104)
Total cash (used in)/provided by operating activities		253,669	208,639
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(30,009)	(37,122)
Purchases of capitalized data and other intangible assets		(27,706)	(25,207)
Cash paid for acquisitions, net of cash acquired		(119,346)	(672,336)
Cash Received From Sale Of Subsidiary		0	25,525
Purchases of investments		(3,748)	0
Proceeds from sale of property and equipment		94	13,937
Change in restricted cash		1,496	(1,443)
Net cash used in investing activities - continuing operations		(179,219)	(696,646)
Net cash used in investing activities - discontinued operations		0	1,536
Total cash used in investing activities		(179,219)	(695,110)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		114,375	690,017
Payments of Debt Issuance Costs		(6,452)	(14,042)
Repayments of long-term debt		(46,999)	(118,836)
Proceeds from issuance of stock related to stock options and employee benefit plans		19,554	5,736
Minimum tax withholdings related to net share settlements		(14,425)	(15,247)
Share repurchased and retired		(97,430)	(72,781)
Excess tax benefit related to stock options		6,284	6,352
Net cash (used in)/provided by financing activities - continuing operations		(25,093)	481,199
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		(25,093)	481,199
Effect of exchange rate on cash		6,757	(144)
Net (decrease)/increase in cash and cash equivalents		56,114	(5,416)
Cash and cash equivalents at beginning of period		104,677	134,419
Less: Change in cash and cash equivalents - discontinued operations		7,584	568
Plus: Cash swept from discontinued operations		(8,118)	(1,953)
Cash and cash equivalents at end of period	$ 160,257	160,257	127,618
Parent [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		(41,922)	(7,831)
Net cash provided by operating activities - discontinued operations		0	0
Total cash (used in)/provided by operating activities		(41,922)	(7,831)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(2,525)	(1,430)
Purchases of capitalized data and other intangible assets		0	0
Cash paid for acquisitions, net of cash acquired		0	0
Cash Received From Sale Of Subsidiary			0
Purchases of investments		0
Proceeds from sale of property and equipment		0	0
Proceeds from Sale, Maturity and Collection of Investments		0
Change in restricted cash		1,259	(1,750)
Net cash used in investing activities - continuing operations		(1,266)	(3,180)
Net cash used in investing activities - discontinued operations		0	0
Total cash used in investing activities		(1,266)	(3,180)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		114,375	690,017
Payments of Debt Issuance Costs		(6,452)	(14,042)
Repayments of long-term debt		(46,474)	(113,967)
Proceeds from issuance of stock related to stock options and employee benefit plans		19,554	5,736
Minimum tax withholdings related to net share settlements		(14,425)	(15,247)
Share repurchased and retired		(97,430)	(72,781)
Excess tax benefit related to stock options		6,284	6,352
Intercompany Payments		(27,377)	(665,031)
Other		116,968	179,187
Net cash (used in)/provided by financing activities - continuing operations		65,023	224
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		65,023	224
Effect of exchange rate on cash		0	0
Net (decrease)/increase in cash and cash equivalents		21,835	(10,787)
Cash and cash equivalents at beginning of period		61,602	104,310
Less: Change in cash and cash equivalents - discontinued operations		0	0
Plus: Cash swept from discontinued operations		(8,118)	(3,489)
Cash and cash equivalents at end of period	75,319	75,319	90,034
Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		280,039	190,961
Net cash provided by operating activities - discontinued operations		(7,584)	(2,104)
Total cash (used in)/provided by operating activities		272,455	188,857
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(20,381)	(28,016)
Purchases of capitalized data and other intangible assets		(23,706)	(22,258)
Cash paid for acquisitions, net of cash acquired		(119,346)	(643,218)
Cash Received From Sale Of Subsidiary			25,525
Purchases of investments		(1,746)
Proceeds from sale of property and equipment		94	13,937
Proceeds from Sale, Maturity and Collection of Investments		0
Change in restricted cash		0	307
Net cash used in investing activities - continuing operations		(165,085)	(653,723)
Net cash used in investing activities - discontinued operations		0	0
Total cash used in investing activities		(165,085)	(653,723)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		0	0
Payments of Debt Issuance Costs		0	0
Repayments of long-term debt		(525)	(4,869)
Proceeds from issuance of stock related to stock options and employee benefit plans		0	0
Minimum tax withholdings related to net share settlements		0	0
Share repurchased and retired		0	0
Excess tax benefit related to stock options		0	0
Intercompany Payments		(116,968)	(179,187)
Other		0	653,885
Net cash (used in)/provided by financing activities - continuing operations		(117,493)	469,829
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		(117,493)	469,829
Effect of exchange rate on cash		0	0
Net (decrease)/increase in cash and cash equivalents		(10,123)	4,963
Cash and cash equivalents at beginning of period		8,733	0
Less: Change in cash and cash equivalents - discontinued operations		(7,584)	2,104
Plus: Cash swept from discontinued operations		0	0
Cash and cash equivalents at end of period	6,194	6,194	7,067
Non-Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		23,136	27,613
Net cash provided by operating activities - discontinued operations		0	0
Total cash (used in)/provided by operating activities		23,136	27,613
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(7,103)	(7,676)
Purchases of capitalized data and other intangible assets		(4,000)	(2,949)
Cash paid for acquisitions, net of cash acquired		0	(29,118)
Cash Received From Sale Of Subsidiary			0
Purchases of investments		(2,002)
Proceeds from sale of property and equipment		0	0
Proceeds from Sale, Maturity and Collection of Investments		0
Change in restricted cash		237	0
Net cash used in investing activities - continuing operations		(12,868)	(39,743)
Net cash used in investing activities - discontinued operations		0	1,536
Total cash used in investing activities		(12,868)	(38,207)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		0	0
Payments of Debt Issuance Costs		0	0
Repayments of long-term debt		0	0
Proceeds from issuance of stock related to stock options and employee benefit plans		0	0
Minimum tax withholdings related to net share settlements		0	0
Share repurchased and retired		0	0
Excess tax benefit related to stock options		0	0
Intercompany Payments		0	0
Other		27,377	11,146
Net cash (used in)/provided by financing activities - continuing operations		27,377	11,146
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		27,377	11,146
Effect of exchange rate on cash		6,757	(144)
Net (decrease)/increase in cash and cash equivalents		44,402	408
Cash and cash equivalents at beginning of period		34,342	30,109
Less: Change in cash and cash equivalents - discontinued operations		0	(1,536)
Plus: Cash swept from discontinued operations		0	1,536
Cash and cash equivalents at end of period	78,744	78,744	30,517
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
Cash Received From Sale Of Subsidiary			0
Purchases of investments		0
Proceeds from sale of property and equipment		0	0
Proceeds from Sale, Maturity and Collection 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
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		0	0
Payments of Debt Issuance Costs		0	0
Repayments of long-term debt		0	0
Proceeds from issuance of stock related to stock options and employee benefit plans		0	0
Minimum tax withholdings related to net share settlements		0	0
Share repurchased and retired		0	0
Excess tax benefit related to stock options		0	0
Intercompany Payments		144,345	844,218
Other		(144,345)	(844,218)
Net cash (used in)/provided by 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	0
Total [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		261,253	210,743
Net cash provided by operating activities - discontinued operations		(7,584)	(2,104)
Total cash (used in)/provided by operating activities		253,669	208,639
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(30,009)	(37,122)
Purchases of capitalized data and other intangible assets		(27,706)	(25,207)
Cash paid for acquisitions, net of cash acquired		(119,346)	(672,336)
Cash Received From Sale Of Subsidiary			25,525
Purchases of investments		(3,748)
Proceeds from sale of property and equipment	13,937	94
Proceeds from Sale, Maturity and Collection of Investments		0
Change in restricted cash		1,496	(1,443)
Net cash used in investing activities - continuing operations		(179,219)	(696,646)
Net cash used in investing activities - discontinued operations		0	1,536
Total cash used in investing activities		(179,219)	(695,110)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		114,375	690,017
Payments of Debt Issuance Costs		(6,452)	(14,042)
Repayments of long-term debt		(46,999)	(118,836)
Proceeds from issuance of stock related to stock options and employee benefit plans		19,554	5,736
Minimum tax withholdings related to net share settlements		(14,425)	(15,247)
Share repurchased and retired		(97,430)	(72,781)
Excess tax benefit related to stock options		6,284	6,352
Intercompany Payments		0	0
Other		0	0
Net cash (used in)/provided by financing activities - continuing operations		(25,093)	481,199
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		(25,093)	481,199
Effect of exchange rate on cash		6,757	(144)
Net (decrease)/increase in cash and cash equivalents		56,114	(5,416)
Cash and cash equivalents at beginning of period		104,677	134,419
Less: Change in cash and cash equivalents - discontinued operations		(7,584)	(568)
Plus: Cash swept from discontinued operations		(8,118)	(1,953)
Cash and cash equivalents at end of period	$ 160,257	$ 160,257	$ 127,618