Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 252,195	$ 209,942	$ 149,922
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	1,700	398	153
Depreciation expense	47,072	48,326	51,262
Stock-based compensation expense-restricted stock and stock units	38,867	41,464	50,906
Excess tax benefits from stock-based compensation	(8,103)	(8,475)	(4,211)
Deferred income taxes	(13,259)	(14,993)	17,156
Provision for doubtful accounts receivable	7,467	7,133	6,673
Changes in assets and liabilities, net of effects of acquisitions:
Increase in accounts receivable	(47,699)	(21,354)	(81,314)
Increase in accounts payable, accrued expenses, accrued payroll costs and retirement obligations	38,356	16,672	64,932
(Decrease) increase in income taxes payable	(11,927)	15,160	6,368
Change in other assets, net of change in other liabilities	4,548	(5,096)	(5,531)
Net cash flows provided by operating activities	309,217	289,177	256,316
CASH FLOWS FROM INVESTING ACTIVITIES:
Payment for acquisitions, net of cash acquired		(14,393)
Capital expenditures	(53,725)	(50,056)	(56,535)
Increase in trusts for employee benefits and retirement plans	(44,052)	(8,577)	(6,867)
Net cash flows used in investing activities	(97,777)	(73,026)	(63,402)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock	(167,975)	(176,794)	(168,103)
Cash dividends paid	(89,187)	(84,129)	(80,303)
Decrease in notes payable and other indebtedness	(4,496)	(107)	(91)
Excess tax benefits from stock-based compensation	8,103	8,475	4,211
Proceeds from exercises of stock options	33,285	42,939	18,309
Net cash flows used in financing activities	(220,270)	(209,616)	(225,977)
Effect of exchange rate changes on cash and cash equivalents	(3,041)	1,764	(2,738)
Net (decrease) increase in cash and cash equivalents	(11,871)	8,299	(35,801)
Cash and cash equivalents at beginning of period	287,635	279,336	315,137
Cash and cash equivalents at end of period	275,764	287,635	279,336
Cash paid during the year for:
Interest	315	405	536
Income taxes, net of refunds	168,407	136,023	76,422
Non-cash items:
Stock repurchases awaiting settlement		$ 5,942	$ 2,466