CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
OPERATING ACTIVITIES
Net income	$ 391,081	$ 383,116
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	52,716	49,513
Provision for doubtful accounts	2,738	11,975
Stock-based compensation	30,626	43,512
Deferred income taxes	21,832	(8,356)
Loss on sale/disposal of assets	566	459
Changes in operating elements (net of acquisitions):
Receivables	(137,813)	(39,051)
Prepaid expenses and other	(12,148)	(6,347)
Other non-current assets	(2,793)	124
Accounts payable and outstanding checks	93,510	23,037
Accrued compensation and profit-sharing contribution	(50,105)	(3,585)
Accrued income taxes	(3,159)	17,774
Other accrued liabilities	(10,223)	(7,728)
Net cash provided by operating activities	376,828	464,443
INVESTING ACTIVITIES
Purchases of property and equipment	(56,125)	(19,317)
Purchases and development of software	(14,986)	(13,494)
Acquisitions, net of cash acquired	(220,203)	(367,108)
Restricted cash	0	359,388
Other	(735)	535
Net cash used for investing activities	(292,049)	(39,996)
FINANCING ACTIVITIES
Proceeds from stock issued for employee benefit plans	16,003	13,036
Stock tendered for payment of withholding taxes	(36,220)	(10,980)
Repurchase of common stock	(109,085)	(161,115)
Cash dividends	(191,129)	(171,448)
Excess tax benefit on stock-based compensation	17,207	7,298
Proceeds from short-term borrowings	4,415,000	5,508,000
Payments on short-term borrowings	(4,140,000)	(5,583,000)
Net cash used for financing activities	(28,224)	(398,209)
Effect of exchange rates on cash	(335)	(12,091)
Net increase in cash and cash equivalents	56,220	14,147
Cash and cash equivalents, beginning of period	168,229	128,940
Cash and cash equivalents, end of period	224,449	143,087
Noncash transactions from investing activities:
Accrued purchases of property and equipment	$ 4,332	$ 0