Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
OPERATING ACTIVITIES
Net income	$ 221,082	$ 208,051
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	16,559	22,609
Depreciation and amortization	17,208	15,299
Provision for doubtful accounts	3,608	4,062
Deferred taxes and other	5,957	(618)
Changes in operating elements:
Receivables	(229,361)	(279,205)
Prepaid expenses and other	(5,631)	(8,451)
Accounts payable and outstanding checks	130,457	130,693
Accrued compensation and profit-sharing contribution	(51,556)	(19,451)
Accrued income taxes and other	1,705	5,865
Net cash provided by operating activities	110,028	78,854
INVESTING ACTIVITIES
Purchases of property and equipment	(17,403)	(11,733)
Purchases and development of software	(7,567)	(8,052)
Sales/maturities of available-for-sale-securities	0	9,311
Other investing activities	192	5
Net cash used for investing activities	(24,778)	(10,469)
FINANCING ACTIVITIES
Payment of contingent purchase price	(11,613)	(4,318)
Proceeds from stock issued for employee benefit plans	10,736	11,780
Stock tendered for payment of withholding taxes	(8,020)	(6,864)
Repurchases of common stock	(105,483)	(64,499)
Excess tax benefit on stock-based compensation	7,654	11,053
Cash dividends	(109,151)	(97,562)
Net cash used for financing activities	(215,877)	(150,410)
Effect of exchange rates on cash	(2,415)	(685)
Net change in cash and cash equivalents	(133,042)	(82,710)
Cash and cash equivalents, beginning of period	373,669	398,607
Cash and cash equivalents, end of period	$ 240,627	$ 315,897