CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
OPERATING ACTIVITIES:
Net income	$ 189,426	$ 245,488
Adjustments to reconcile net income to net cash provided by operating activities:
Stock compensation expense	16,158	13,365
Excess tax benefit of stock options exercised	(15,483)	(10,747)
Depreciation	55,476	55,388
Amortization	26,957	24,214
Deferred income taxes	(17,169)	8,833
Change in fair value of contingent consideration	(640)	3,953
Other, net	6,326	1,379
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable	(66,352)	(25,420)
Accounts payable	29,170	13,383
Accrued liabilities	77,820	17,640
Deferred revenues	(3,412)	2,326
Other assets and liabilities	(4,986)	(4,830)
Net cash provided by operating activities	293,291	344,972
INVESTING ACTIVITIES:
Payments for acquisitions, net of cash acquired	(97,098)	(328,811)
Purchases of investments	(635,919)	(2,051)
Capital expenditures	(72,566)	(66,262)
Net cash used in investing activities	(805,583)	(397,124)
FINANCING ACTIVITIES:
Repayments of long-term debt and other obligations	(61,805)	(45,031)
Proceeds from foreign bank debt	42,535	151,605
Repayments of foreign bank debt	(76,387)	(136,025)
Proceeds from term loan	250,000	0
Repayment of term loan	(250,000)	0
Proceeds from private placement of long-term note	300,000	0
Repayments of private placement of long-term note	(100,000)	0
Proceeds from senior credit facility	1,338,140	1,154,100
Repayments of senior credit facility	(1,614,968)	(979,059)
Payments on capital lease obligations	(2,813)	(4,014)
Payments of deferred financing costs	0	(2,280)
Payment for hedge	(8,833)	0
Purchases and cancellations of treasury stock	(103,029)	(157,004)
Proceeds from issuance of mandatory convertible preferred stock	746,900	0
Proceeds from issuance of common stock	53,529	33,904
Excess tax benefit of stock options exercised	15,483	10,747
Payments to noncontrolling interests	(5,236)	(732)
Net cash provided by financing activities	523,516	26,211
Effect of exchange rate changes on cash and cash equivalents	(577)	759
Net increase/ (decrease) in cash and cash equivalents	10,647	(25,182)
Cash and cash equivalents at beginning of period	22,236	67,167
Cash and cash equivalents at end of period	32,883
NON-CASH ACTIVITIES:
Issuances of obligations for acquisitions	$ 71,905	$ 100,944