CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES:
Net Income	$ 207,899	$ 268,013	$ 328,146
Adjustments to reconcile net income to net cash provided by operating activities:
Stock compensation expense	20,455	21,750	17,773
Excess tax benefit of stock options exercised		(16,897)	(17,906)
Depreciation	123,246	81,914	71,924
Amortization	129,300	45,498	32,692
Deferred income taxes	7,078	(10,294)	16,550
Asset impairment charges	28,472	1,781
Other, net	975	5,686	8,932
Changes in operating assets and liabilities, net of effect of acquisitions and divestitures:
Accounts receivable	(43,136)	(55,890)	(34,116)
Accounts payable	4,624	26,366	(5,712)
Accrued liabilities	28,527	26,060	21,279
Deferred revenues	1,383	(4,615)	1,017
Other assets and liabilities	38,426	956	7,921
Net cash provided by operating activities	547,249	390,328	448,500
INVESTING ACTIVITIES:
Payments for acquisitions, net of cash acquired	(63,917)	(2,419,437)	(374,321)
Proceeds from/ (purchases of) investments	7	294	(1,957)
Proceeds from insurance settlement	2,358
Proceeds from sale of business	790
Proceeds from sale of property and equipment	1,316
Capital expenditures	(136,160)	(114,761)	(86,496)
Net cash used in investing activities	(195,606)	(2,533,904)	(462,774)
FINANCING ACTIVITIES:
Repayments of long-term debt and other obligations	(89,215)	(93,172)	(101,231)
Proceeds from foreign bank debt	76,237	53,747	205,086
Repayments of foreign bank debt	(84,114)	(87,308)	(193,284)
Proceeds from term loan		1,550,000	0
Repayment of term loan	(250,000)	(300,000)	0
Proceeds from private placement of long-term note		600,000	0
Repayments of private placement of long-term note		(100,000)	0
Proceeds from senior credit facility	1,464,902	1,907,402	1,413,026
Repayments of senior credit facility	(1,393,323)	(2,004,385)	(1,216,031)
Payments of capital lease obligations	(5,313)	(3,865)	(5,826)
Payments of deferred financing costs	(605)	(9,903)	(2,280)
Payment for hedge		(8,833)
Payments for repurchase of common stock	(40,814)	(130,576)	(194,066)
Payments for repurchase of mandatory convertible preferred stock	(30,910)
Proceeds from issuance of mandatory convertible preferred stock		746,900	0
Proceeds from issuance of common stock	37,504	60,124	51,852
Dividends paid on mandatory convertible preferred stock	(39,414)	(10,106)	0
Excess tax benefit of stock options exercised		16,897	17,906
Payments to noncontrolling interests	(8,190)	(5,714)	(5,201)
Net cash (used in)/ provided by financing activities	(363,255)	2,181,208	(30,049)
Effect of exchange rate changes on cash and cash equivalents	167	(4,234)	(608)
Net (decrease)/ increase in cash and cash equivalents	(11,445)	33,398	(44,931)
Cash and cash equivalents at beginning of period	55,634	22,236	67,167
Cash and cash equivalents at end of period	44,189	55,634	22,236
NON-CASH ACTIVITIES:
Issuances of obligations for acquisitions	$ 44,230	$ 80,189	$ 145,938