CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
OPERATING ACTIVITIES:
Net income	$ 79,770	$ 75,222
Adjustments to reconcile net income to net cash provided by operating activities:
Stock compensation expense	4,672	4,047
Excess tax benefit of stock options exercised	(3,734)	(4,203)
Depreciation	16,041	14,846
Amortization	7,315	6,642
Deferred income taxes	6,175	10,407
Change in fair value of contingent consideration	4,789	0
Changes in operating assets and liabilities, net of effect of acquisitions and divestitures:
Accounts receivable	4,529	(19,769)
Accounts payable	5,279	1,169
Accrued liabilities	14,189	7,412
Deferred revenues	2,642	(1,345)
Other assets and liabilities	2,808	3,742
Net cash provided by operating activities	144,475	98,170
INVESTING ACTIVITIES:
Payments for acquisitions, net of cash acquired	(12,262)	(18,899)
Payments for (Proceeds from) Investments	(1,947)	20
Capital expenditures	(16,420)	(16,480)
Net cash used in investing activities	(30,629)	(35,359)
FINANCING ACTIVITIES:
Repayments of long-term debt and other obligations	(12,430)	(9,996)
Borrowings on foreign bank debt	36,640	27,651
Repayments on foreign bank debt	(37,157)	(62,027)
Borrowings on senior credit facility	149,000	291,132
Repayments on senior credit facility	(203,377)	(337,683)
Payments on capital lease obligations	(876)	(837)
Purchases and cancellations of treasury stock	(76,914)	(7,160)
Proceeds from issuance of common stock	8,655	13,915
Excess tax benefit of stock options exercised	3,734	4,203
Payments to noncontrolling interests	(97)	0
Net cash used in financing activities	(132,822)	(80,802)
Effect of exchange rate changes on cash and cash equivalents	43	(611)
Net decrease in cash and cash equivalents	(18,933)	(18,602)
Cash and cash equivalents at beginning of period	61,991	31,324
Cash and cash equivalents at end of period	43,058	12,722
NON-CASH ACTIVITIES:
Issuances of obligations for acquisitions	$ 13,095	$ 10,454