Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net earnings	$ 516,361	$ 494,150	$ 448,636
Adjustments to reconcile net earnings to net cash provided by operating activities, net of acquisitions:
Depreciation of property and equipment	86,071	72,145	63,770
Gain on sale of property and equipment	(1,411)	(964)	(643)
Bad debt expense	8,769	11,480	9,421
Deferred income taxes	8,290	1,760	8,129
Stock-based compensation	5,841	7,039	5,400
Excess tax benefits from stock-based compensation	(3,390)	(2,094)	(2,787)
Amortization of non-compete agreements	527	527	421
Changes in operating assets and liabilities, net of acquisitions:
Trade accounts receivable	(20,608)	(63,418)	(51,593)
Inventories	(47,830)	(87,622)	(68,685)
Other current assets	(15,778)	(7,510)	(10,627)
Accounts payable	20,617	12,501	13,234
Accrued expenses	11,141	25,263	22,424
Income taxes	(26,610)	34,405	(14,714)
Other	4,950	1,730	(6,266)
Net cash provided by operating activities	546,940	499,392	416,120
Cash flows from investing activities:
Purchases of property and equipment	(155,168)	(189,474)	(206,540)
Cash paid for acquisitions	(23,493)	(5,575)	0
Proceeds from sale of property and equipment	9,941	5,819	4,990
Net decrease (increase) in marketable securities	0	451	(97)
Other	(11,907)	(2)	(145)
Net cash used in investing activities	(180,627)	(188,781)	(201,792)
Cash flows from financing activities:
Borrowings under credit facility	1,215,000	705,000	260,000
Payments against credit facility	(955,000)	(615,000)	(260,000)
Proceeds from exercise of stock options	19,099	7,697	9,306
Excess tax benefits from stock-based compensation	3,390	2,094	2,787
Purchases of common stock	(292,951)	(52,942)	(9,080)
Payments of dividends	(327,101)	(296,581)	(237,456)
Net cash used in financing activities	(337,563)	(249,732)	(234,443)
Effect of exchange rate changes on cash and cash equivalents	(14,227)	(4,889)	(990)
Net increase in cash and cash equivalents	14,523	55,990	(21,105)
Cash and cash equivalents at beginning of year	114,496	58,506	79,611
Cash and cash equivalents at end of year	129,019	114,496	58,506
Supplemental disclosure of cash flow information:
Cash paid during each year for interest	3,103	915	113
Net cash paid during each year for income taxes	$ 327,034	$ 257,514	$ 270,615