Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net earnings	$ 420,536	$ 357,929	$ 265,356
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation of property and equipment	53,459	44,113	40,688
(Gain) Loss on sale of property and equipment	(403)	194	35
Bad debt expense	9,726	9,217	8,658
Deferred income taxes	15,442	15,747	1,602
Stock based compensation	4,800	4,050	4,030
Excess tax benefits from stock based compensation	(10,149)	0	0
Amortization of non-compete agreements	593	593	67
Changes in operating assets and liabilities:
Trade accounts receivable	(43,291)	(77,678)	(64,622)
Inventories	(69,231)	(88,783)	(48,964)
Other current assets	(7,528)	(19,294)	(24,577)
Accounts payable	4,240	13,305	6,984
Accrued expenses	14,193	15,550	30,393
Income taxes	704	(3,222)	16,956
Other	3,201	(3,232)	3,882
Net cash provided by operating activities	396,292	268,489	240,488
Cash flows from investing activities:
Purchase of property and equipment	(138,406)	(120,043)	(73,597)
Proceeds from sale of property and equipment	4,524	3,554	4,459
Net decrease (increase) in marketable securities	26,811	4,054	(581)
(Increase) decrease in other assets	(133)	212	(10,329)
Net cash used in investing activities	(107,204)	(112,223)	(80,048)
Cash flows from financing activities:
Proceeds from exercise of stock options	29,644	8,939	0
Excess tax benefits from stock based compensation	10,149	983	0
Payment of dividends	(367,306)	(191,741)	(182,814)
Net cash used in financing activities	(327,513)	(181,819)	(182,814)
Effect of exchange rate changes on cash	360	(464)	1,215
Net decrease in cash and cash equivalents	(38,065)	(26,017)	(21,159)
Cash and cash equivalents at beginning of year	117,676	143,693	164,852
Cash and cash equivalents at end of year	79,611	117,676	143,693
Supplemental disclosure of cash flow information:
Cash paid during each year for income taxes	$ 268,357	$ 205,614	$ 146,726