CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
OPERATING ACTIVITIES:
Net income	$ 245,488	$ 234,497
Adjustments to reconcile net income to net cash provided by operating activities:
Stock compensation expense	13,365	12,088
Excess tax benefit of stock options exercised	(10,747)	(12,354)
Depreciation	55,388	45,229
Amortization	24,214	19,884
Deferred income taxes	8,833	15,623
Change in fair value of contingent consideration	3,953	(307)
Other	1,379	0
Changes in operating assets and liabilities, net of effect of acquisitions and divestitures:
Accounts receivable	(25,420)	(43,816)
Accounts payable	13,383	3,258
Accrued liabilities	17,640	21,420
Deferred revenues	2,326	(614)
Other assets and liabilities	(4,830)	41,181
Net cash provided by operating activities	344,972	336,089
INVESTING ACTIVITIES:
Payments for acquisitions, net of cash acquired	(328,811)	(131,902)
(Purchases of)/ proceeds from investments	(2,051)	45
Capital expenditures	(66,262)	(54,329)
Net cash used in investing activities	(397,124)	(186,186)
FINANCING ACTIVITIES:
Repayments of long-term debt and other obligations	(45,031)	(48,858)
Borrowings on foreign bank debt	151,605	164,669
Repayments on foreign bank debt	(136,025)	(163,941)
Borrowings on senior credit facility	1,154,100	731,015
Repayments on senior credit facility	(979,059)	(725,940)
Payments on capital lease obligations	(4,014)	(2,623)
Payments of deferred financing costs	(2,280)	0
Purchases and cancellations of treasury stock	(157,004)	(114,531)
Proceeds from issuance of common stock	33,904	33,827
Excess tax benefit of stock options exercised	10,747	12,354
Payments to noncontrolling interests	(732)	(1,018)
Net cash provided by/ (used in) financing activities	26,211	(115,046)
Effect of exchange rate changes on cash and cash equivalents	759	(1,795)
Net (decrease)/ increase in cash and cash equivalents	(25,182)	33,062
Cash and cash equivalents at beginning of period	67,167	34,659
Cash and cash equivalents at end of period	41,985	67,721
NON-CASH ACTIVITIES:
Issuances of obligations for acquisitions	100,944	88,530
Issuances of obligations for purchases of noncontrolling interest	$ 0	$ 2,113