CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 118,952	$ 93,663
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	867	87
Depreciation expense	23,326	24,280
Stock-based compensation expense-restricted stock and stock units	17,976	20,205
Excess tax benefits from stock-based compensation	(1,280)	(2,895)
Deferred income taxes	(13,286)	(13,973)
Provision for doubtful accounts receivable	3,063	4,644
Changes in assets and liabilities:
Increase in accounts receivable	(54,751)	(44,317)
Increase (decrease) in accounts payable, accrued expenses, accrued payroll costs and retirement obligations	23,734	(3,114)
Increase in income taxes payable	15,265	38,650
Change in other assets, net of change in other liabilities	(3,931)	(1,944)
Net cash flows provided by operating activities	129,935	115,286
CASH FLOWS FROM INVESTING ACTIVITIES:
Payment for acquisitions, net of cash acquired		(1,484)
Capital expenditures	(19,104)	(24,211)
Increase in trusts for employee benefits and retirement plans	(33,076)	(3,596)
Net cash flows used in investing activities	(52,180)	(29,291)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock	(86,381)	(101,380)
Cash dividends paid	(43,886)	(41,874)
Decrease in notes payable and other indebtedness	(4,388)	(55)
Excess tax benefits from stock-based compensation	1,280	2,895
Proceeds from exercises of stock options	22,396	35,391
Net cash flows used in financing activities	(110,979)	(105,023)
Effect of exchange rate changes on cash and cash equivalents	(7,440)	(1,730)
Net decrease in cash and cash equivalents	(40,664)	(20,758)
Cash and cash equivalents at beginning of period	287,635	279,336
Cash and cash equivalents at end of period	$ 246,971	$ 258,578