Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 149,922	$ 66,069	$ 37,263
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	153	411	1,460
Depreciation expense	51,262	55,547	63,806
Stock-based compensation expense-restricted stock and stock units	50,906	56,949	60,320
Stock-based compensation expense-stock options		170	828
Excess tax benefits from stock-based compensation	(4,211)	(5,814)	(4,751)
Provision for deferred income taxes	17,156	7,370	5,752
Provision for doubtful accounts receivable	6,673	6,795	(839)
Changes in assets and liabilities, net of effects of acquisitions:
(Increase) decrease in accounts receivable	(81,314)	(68,008)	133,541
Increase (decrease) in accounts payable, accrued expenses, accrued payroll costs and retirement obligations	64,932	41,626	(52,210)
Increase (decrease) in income taxes payable	6,368	1,490	(3,830)
Change in other assets, net of change in other liabilities	(5,531)	13,278	(1,187)
Net cash flows provided by operating activities	256,316	175,883	240,153
CASH FLOWS FROM INVESTING ACTIVITIES:
Payment for acquisitions, net of cash acquired		(585)
Capital expenditures	(56,535)	(35,088)	(41,248)
Increase in trusts for employee benefits and retirement plans	(6,867)	(3,424)	(4,719)
Net cash flows used in investing activities	(63,402)	(39,097)	(45,967)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock	(168,103)	(155,460)	(149,818)
Cash dividends paid	(80,303)	(76,591)	(72,149)
Decrease in notes payable and other indebtedness	(91)	(113)	(105)
Excess tax benefits from stock-based compensation	4,211	5,814	4,751
Proceeds from exercises of stock options	18,309	38,355	24,951
Net cash flows used in financing activities	(225,977)	(187,995)	(192,370)
Effect of exchange rate changes on cash and cash equivalents	(2,738)	552	9,222
Net (decrease) increase in cash and cash equivalents	(35,801)	(50,657)	11,038
Cash and cash equivalents at beginning of period	315,137	365,794	354,756
Cash and cash equivalents at end of period	279,336	315,137	365,794
Cash paid during the year for:
Interest	536	599	441
Income taxes, net of refunds	76,422	38,249	21,759
Non-cash items:
Stock repurchases awaiting settlement	$ 2,466