Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net earnings	$ 494,150	$ 448,636	$ 420,536
Adjustments to reconcile net earnings to net cash provided by operating activities, net of acquisition:
Depreciation of property and equipment	72,145	63,770	53,459
Gain on sale of property and equipment	(964)	(643)	(403)
Bad debt expense	11,480	9,421	9,726
Deferred income taxes	1,760	8,129	15,442
Stock-based compensation	7,039	5,400	4,800
Excess tax benefits from stock-based compensation	(2,094)	(2,787)	(10,149)
Amortization of non-compete agreements	527	421	593
Changes in operating assets and liabilities, net of acquisition:
Trade accounts receivable	(63,418)	(51,593)	(43,291)
Inventories	(87,622)	(68,685)	(69,231)
Other current assets	(7,510)	(10,627)	(7,528)
Accounts payable	12,501	13,234	4,240
Accrued expenses	25,263	22,424	14,193
Income taxes	34,405	(14,714)	704
Other	1,730	(6,266)	3,201
Net cash provided by operating activities	499,392	416,120	396,292
Cash flows from investing activities:
Purchases of property and equipment	(189,474)	(206,540)	(138,406)
Cash paid for acquisition	(5,575)	0	0
Proceeds from sale of property and equipment	5,819	4,990	4,524
Net decrease (increase) in marketable securities	451	(97)	26,811
Net increase in other assets	(2)	(145)	(133)
Net cash used in investing activities	(188,781)	(201,792)	(107,204)
Cash flows from financing activities:
Borrowings under line of credit	705,000	260,000	0
Payments against line of credit	(615,000)	(260,000)	0
Proceeds from exercise of stock options	7,697	9,306	29,644
Excess tax benefits from stock-based compensation	2,094	2,787	10,149
Purchases of common stock	(52,942)	(9,080)	0
Payments of dividends	(296,581)	(237,456)	(367,306)
Net cash used in financing activities	(249,732)	(234,443)	(327,513)
Effect of exchange rate changes on cash and cash equivalents	(4,889)	(990)	360
Net increase (decrease) in cash and cash equivalents	55,990	(21,105)	(38,065)
Cash and cash equivalents at beginning of year	58,506	79,611	117,676
Cash and cash equivalents at end of year	114,496	58,506	79,611
Supplemental disclosure of cash flow information:
Cash paid during each year for interest	915	113	0
Net cash paid during each year for income taxes	$ 257,514	$ 270,615	$ 268,357