Guarantor Subsidiaries (Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2014
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		$ 133,127	$ 128,103
Net cash provided by operating activities - discontinued operations		(7,372)	7,430
Total cash (used in)/provided by operating activities		125,755	135,533
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(21,496)	(26,296)
Purchases of capitalized data and other intangible assets		(18,707)	(16,533)
Cash paid for acquisitions, net of cash acquired			(670,036)
Purchases of investments		(2,516)	0
Proceeds from sale of property and equipment		0	36
Change in restricted cash		654	(494)
Net cash used in investing activities - continuing operations		(42,065)	(713,323)
Net cash used in investing activities - discontinued operations		0	0
Total cash used in investing activities		(42,065)	(713,323)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		14,375	690,017
Payments of Debt Issuance Costs		(6,452)	(14,042)
Repayments of long-term debt		(36,078)	(56,550)
Share repurchased and retired		(58,720)	(32,041)
Proceeds from issuance of stock related to stock options and employee benefit plans		18,109	4,440
Minimum tax withholding paid on behalf of employees for restricted stock units		(12,742)	(15,034)
Excess tax benefit related to stock options		5,641	6,275
Net cash (used in)/provided by financing activities - continuing operations		(75,867)	583,065
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		(75,867)	583,065
Effect of exchange rate on cash		1,132	903
Net (decrease)/increase in cash and cash equivalents		8,955	6,178
Cash and cash equivalents at beginning of period		104,677	134,419
Less: Change in cash and cash equivalents - discontinued operations		7,372	(7,430)
Plus: Cash swept from discontinued operations		(7,876)	7,057
Cash and cash equivalents at end of period	$ 113,128	113,128	140,224
Parent [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		(31,881)	(6,141)
Net cash provided by operating activities - discontinued operations		0	0
Total cash (used in)/provided by operating activities		(31,881)	(6,141)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(1,395)	(1,166)
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 sale of property and equipment			0
Change in restricted cash		524	(700)
Net cash used in investing activities - continuing operations		(871)	(1,866)
Net cash used in investing activities - discontinued operations		0	0
Total cash used in investing activities		(871)	(1,866)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		14,375	690,017
Payments of Debt Issuance Costs		(6,452)	(14,042)
Repayments of long-term debt		(35,773)	(51,892)
Share repurchased and retired		(58,720)	(32,041)
Proceeds from issuance of stock related to stock options and employee benefit plans		18,109	4,440
Minimum tax withholding paid on behalf of employees for restricted stock units		(12,742)	(15,034)
Excess tax benefit related to stock options		5,641	6,275
Intercompany Payments		0	(661,974)
Other		126,093	76,617
Net cash (used in)/provided by financing activities - continuing operations		50,531	2,366
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		50,531	2,366
Effect of exchange rate on cash		0	0
Net (decrease)/increase in cash and cash equivalents		17,779	(5,641)
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		(7,876)	7,057
Cash and cash equivalents at end of period	71,505	71,505	105,726
Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		145,821	116,046
Net cash provided by operating activities - discontinued operations		(7,372)	7,430
Total cash (used in)/provided by operating activities		138,449	123,476
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(14,585)	(19,415)
Purchases of capitalized data and other intangible assets		(15,811)	(14,327)
Cash paid for acquisitions, net of cash acquired			(640,918)
Purchases of investments		(1,746)
Proceeds from sale of property and equipment			36
Change in restricted cash		0	307
Net cash used in investing activities - continuing operations		(32,142)	(674,317)
Net cash used in investing activities - discontinued operations		0	0
Total cash used in investing activities		(32,142)	(674,317)
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		(305)	(4,658)
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
Excess tax benefit related to stock options		0	0
Intercompany Payments		(117,906)	(76,617)
Other		0	644,191
Net cash (used in)/provided by financing activities - continuing operations		(118,211)	562,916
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		(118,211)	562,916
Effect of exchange rate on cash		0	0
Net (decrease)/increase in cash and cash equivalents		(11,904)	12,075
Cash and cash equivalents at beginning of period		8,733	0
Less: Change in cash and cash equivalents - discontinued operations		(7,372)	(7,430)
Plus: Cash swept from discontinued operations		0	0
Cash and cash equivalents at end of period	4,201	4,201	4,645
Non-Guarantor Subsidiaries [Member]
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net cash (used in)/provided by operating activities - continuing operations		19,187	18,198
Net cash provided by operating activities - discontinued operations		0	0
Total cash (used in)/provided by operating activities		19,187	18,198
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(5,516)	(5,715)
Purchases of capitalized data and other intangible assets		(2,896)	(2,206)
Cash paid for acquisitions, net of cash acquired			(29,118)
Purchases of investments		(770)
Proceeds from sale of property and equipment			0
Change in restricted cash		130	(101)
Net cash used in investing activities - continuing operations		(9,052)	(37,140)
Net cash used in investing activities - discontinued operations		0	0
Total cash used in investing activities		(9,052)	(37,140)
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
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
Excess tax benefit related to stock options		0	0
Intercompany Payments		(8,187)	0
Other		0	17,783
Net cash (used in)/provided by financing activities - continuing operations		(8,187)	17,783
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		(8,187)	17,783
Effect of exchange rate on cash		1,132	903
Net (decrease)/increase in cash and cash equivalents		3,080	(256)
Cash and cash equivalents at beginning of period		34,342	30,109
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	37,422	37,422	29,853
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 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	0
Payments of Debt Issuance Costs		0	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
Excess tax benefit related to stock options		0	0
Intercompany Payments		126,093	738,591
Other		(126,093)	(738,591)
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		133,127	128,103
Net cash provided by operating activities - discontinued operations		(7,372)	7,430
Total cash (used in)/provided by operating activities		125,755	135,533
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchases of property and equipment		(21,496)	(26,296)
Purchases of capitalized data and other intangible assets		(18,707)	(16,533)
Cash paid for acquisitions, net of cash acquired			(670,036)
Purchases of investments		(2,516)
Proceeds from sale of property and equipment	36
Change in restricted cash		654	(494)
Net cash used in investing activities - continuing operations		(42,065)	(713,323)
Net cash used in investing activities - discontinued operations		0	0
Total cash used in investing activities		(42,065)	(713,323)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from long-term debt		14,375	690,017
Payments of Debt Issuance Costs		(6,452)	(14,042)
Repayments of long-term debt		(36,078)	(56,550)
Share repurchased and retired		(58,720)	(32,041)
Proceeds from issuance of stock related to stock options and employee benefit plans		18,109	4,440
Minimum tax withholding paid on behalf of employees for restricted stock units		(12,742)	(15,034)
Excess tax benefit related to stock options		5,641	6,275
Intercompany Payments		0	0
Other		0	0
Net cash (used in)/provided by financing activities - continuing operations		(75,867)	583,065
Net cash provided by financing activities - discontinued operations		0	0
Total cash (used in)/provided by financing activities		(75,867)	583,065
Effect of exchange rate on cash		1,132	903
Net (decrease)/increase in cash and cash equivalents		8,955	6,178
Cash and cash equivalents at beginning of period		104,677	134,419
Less: Change in cash and cash equivalents - discontinued operations		(7,372)	7,430
Plus: Cash swept from discontinued operations		(7,876)	7,057
Cash and cash equivalents at end of period	$ 113,128	$ 113,128	$ 140,224