Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 152,162	$ 106,550	$ 128,996
Less: Income/(loss) from discontinued operations, net of tax	2,315	(1,466)	(556)
Less: Gain/(loss) from sale of discontinued operations, net of tax	313	(1,930)	0
Net income from continuing operations	149,534	109,946	129,552
Adjustments to reconcile net income from continuing operations to net cash provided by operating activities:
Depreciation and amortization	177,806	172,578	150,377
Amortization of debt issuance costs	5,650	5,785	6,259
Provision for bad debts and claim losses	16,725	18,869	8,260
Share-based compensation	35,867	39,849	35,786
Tax benefit related to stock options	0	(2,315)	(6,513)
Equity in losses/(earnings) of investee, net of taxes	1,186	(496)	(13,720)
(Gain)/loss on sale of property and equipment	(246)	(31)	24
Loss on early extinguishment of debt	1,775	26,624	1,589
Deferred income tax	(40,769)	18,213	35,110
Impairment loss on investment in affiliates	3,811	23,431	0
Tax indemnification release	0	23,350	0
Loss/(gain) on investments and other, net	2,316	(19,779)	(33,831)
Change in operating assets and liabilities, net of acquisitions:
Accounts receivable	15,522	(24,391)	(15,400)
Prepaid expenses and other assets	4,942	2,823	7,104
Accounts payable and accrued expenses	(44,629)	(29,267)	(45,289)
Deferred revenue	36,577	53,682	68,410
Income taxes	(43)	28,740	(32,771)
Dividends received from investments in affiliates	1,198	9,044	30,084
Other assets and other liabilities	12,708	(42,652)	11,118
Net cash provided by operating activities - continuing operations	379,930	414,003	336,149
Net cash provided by/(used in) operating activities - discontinued operations	3,655	(444)	(7,612)
Total cash provided by operating activities	383,585	413,559	328,537
Cash flows from investing activities:
Purchases of subsidiary shares from and other decreases in noncontrolling interests	0	(18,023)	0
Purchases of property and equipment	(40,508)	(45,211)	(44,149)
Purchases of capitalized data and other intangible assets	(34,990)	(35,507)	(36,409)
Cash paid for acquisitions, net of cash acquired	(189,923)	(396,941)	(194,491)
Purchases of investments	(5,900)	(3,366)	(3,748)
Proceeds from sale of marketable securities	0	21,819	0
Proceeds from sale of property and equipment	335	31	137
Proceeds from sale of investments	1,000	2,451	0
Change in restricted cash	7,947	(7,017)	1,434
Net cash used in investing activities - continuing operations	(262,039)	(481,764)	(277,226)
Net cash provided by investing activities - discontinued operations	0	0	0
Total cash used in investing activities	(262,039)	(481,764)	(277,226)
Cash flows from financing activities:
Proceeds from long-term debt	1,995,000	962,000	114,375
Debt issuance costs	(14,294)	(6,314)	(6,452)
Debt extinguishment premium	0	(16,271)	0
Repayments of long-term debt	(1,842,290)	(709,983)	(82,891)
Shares repurchased and retired	(207,416)	(195,003)	(97,430)
Proceeds from issuance of shares in connection with share-based compensation	9,595	14,907	22,569
Minimum tax withholdings related to net share settlements	(14,043)	(10,507)	(15,230)
Tax benefit related to stock options	0	2,315	6,513
Net cash (used in)/provided by financing activities - continuing operations	(73,448)	41,144	(58,546)
Net cash used in financing activities - discontinued operations	0	0	0
Total cash (used in)/provided by financing activities	(73,448)	41,144	(58,546)
Effect of exchange rate on cash	(1,325)	2	2,182
Net change in cash and cash equivalents	46,773	(27,059)	(5,053)
Cash and cash equivalents at beginning of year	72,031	99,090	104,677
Less: Change in cash and cash equivalents of discontinued operations	3,655	(444)	(7,612)
Plus: Cash swept from/(to) discontinued operations	3,655	(444)	(8,146)
Cash and cash equivalents at end of year	118,804	72,031	99,090
Supplemental disclosures of cash flow information:
Cash paid for interest	53,455	58,566	64,679
Cash paid for income taxes	71,697	31,382	47,783
Cash refunds from income taxes	9,413	537	3,737
Capital expenditures included in accounts payable and accrued liabilities	$ 5,524	$ 23,108	$ 5,909