CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
OPERATING ACTIVITIES:
Net income	$ 162,447	$ 153,665
Adjustments to reconcile net income to net cash provided by operating activities:
Stock compensation expense	9,124	7,943
Excess tax benefit of stock options exercised	(7,080)	(8,373)
Depreciation	35,120	30,088
Amortization	15,717	13,175
Deferred income taxes	8,929	13,101
Change in fair value of contingent consideration	3,953	(122)
Changes in operating assets and liabilities, net of effect of acquisitions and divestitures:
Accounts receivable	(9,606)	(42,871)
Accounts payable	10,646	10,186
Accrued liabilities	(6,809)	(2,566)
Deferred revenues	2,332	(548)
Other assets and liabilities	13,575	2,903
Net cash provided by operating activities	238,348	176,581
INVESTING ACTIVITIES:
Payments for acquisitions, net of cash acquired	(304,832)	(63,401)
(Purchases of)/ proceeds from investments	(2,052)	33
Capital expenditures	(43,668)	(37,441)
Net cash used in investing activities	(350,552)	(100,809)
FINANCING ACTIVITIES:
Repayments of long-term debt and other obligations	(28,005)	(32,016)
Borrowings on foreign bank debt	96,828	92,733
Repayments on foreign bank debt	(85,192)	(96,512)
Borrowings on senior credit facility	933,101	527,469
Repayments on senior credit facility	(732,059)	(544,183)
Payments on capital lease obligations	(1,993)	(1,825)
Payments of deferred financing costs	(2,280)	0
Purchases and cancellations of treasury stock	(137,186)	(66,175)
Proceeds from issuance of common stock	21,195	23,667
Excess tax benefit of stock options exercised	7,080	8,373
Payments to noncontrolling interests	732	0
Net cash provided by/ (used in) financing activities	70,757	(88,469)
Effect of exchange rate changes on cash and cash equivalents	(394)	(528)
Net decrease in cash and cash equivalents	(41,841)	(13,225)
Cash and cash equivalents at beginning of period	67,167	34,659
Cash and cash equivalents at end of period	25,326	21,434
NON-CASH ACTIVITIES:
Issuances of obligations for acquisitions	$ 83,864	$ 22,906