CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities:
Net income	$ 200,324	$ 171,378
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	63,765	60,340
Amortization of debt issuance costs and discount	3,372	5,800
Amortization of accumulated other comprehensive loss on terminated interest rate swaps	3,100	1,651
Share-based compensation	18,765	20,321
Loss (earnings) from unconsolidated affiliates	5,612	(2,603)
Benefit from deferred income taxes	(2,646)	(375)
Excess income tax benefits from share-based award activities	(5,096)	(29,565)
Changes in operating assets and liabilities:
Change in accounts receivable, unbilled services and unearned income	(81,230)	(177,494)
Change in other operating assets and liabilities	(53,234)	(63,023)
Net cash provided by (used in) operating activities	152,732	(13,570)
Investing activities:
Acquisition of property, equipment and software	(57,373)	(31,924)
Purchase of trading securities	(39,036)
Proceeds from corporate owned life insurance policies	20,938
Proceeds from sale of cost method investments	26,042
Investments in unconsolidated affiliates, net of payments received	(10,417)	(3,431)
Termination of interest rate swaps		(10,981)
Other	290	870
Net cash used in investing activities	(59,556)	(45,466)
Financing activities:
Proceeds from issuance of debt		2,248,500
Payment of debt issuance costs		(21,857)
Repayment of debt and principal payments on capital lease obligations	(24,831)	(2,035,051)
Stock issued under employee stock purchase and option plans	14,832	45,308
Repurchase of common stock	(97,637)	(250,000)
Excess income tax benefits from share-based award activities	5,096	29,565
Net cash (used in) provided by financing activities	(102,540)	16,465
Effect of foreign currency exchange rate changes on cash	(12,103)	(21,172)
Decrease in cash and cash equivalents	(21,467)	(63,743)
Cash and cash equivalents at beginning of period	977,151	867,358
Cash and cash equivalents at end of period	$ 955,684	$ 803,615