Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net earnings	$ 321,820	$ 270,458
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation of property and equipment	39,153	32,441
(Gain) loss on sale of property and equipment	(266)	183
Bad debt expense	7,240	6,591
Deferred income taxes	4,817	1,134
Stock based compensation	3,450	2,925
Excess tax benefits from stock based compensation	(8,957)	0
Amortization of non-compete agreements	445	445
Changes in operating assets and liabilities:
Trade accounts receivable	(79,679)	(97,533)
Inventories	(29,676)	(60,780)
Other current assets	(10,301)	(13,848)
Accounts payable	11,103	26,365
Accrued expenses	11,217	12,156
Income taxes	14,835	18,163
Other	3,895	(4,519)
Net cash provided by operating activities	289,096	194,181
Cash flows from investing activities:
Purchase of property and equipment	(88,323)	(92,479)
Proceeds from sale of property and equipment	1,102	2,886
Net (increase) decrease in marketable securities	(63)	5,016
(Increase) decrease in other assets	(122)	301
Net cash used in investing activities	(87,406)	(84,276)
Cash flows from financing activities:
Proceeds from exercise of stock options	23,785	7,706
Excess tax benefits from stock based compensation	8,957	801
Payment of dividends	(156,810)	(150,414)
Net cash used in financing activities	(124,068)	(141,907)
Effect of exchange rate changes on cash	305	(643)
Net increase (decrease) in cash and cash equivalents	77,927	(32,645)
Cash and cash equivalents at beginning of period	117,676	143,693
Cash and cash equivalents at end of period	195,603	111,048
Supplemental disclosure of cash flow information:
Cash paid during each period for income taxes	$ 184,166	$ 145,358