Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities
Net income	$ 50,971	$ 41,918	$ 50,900
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on sale of assets	2,038	166	191
Depreciation and amortization	27,518	26,857	20,751
Impairment of long-lived assets	1,025	803	1,094
Impairment of Goodwill		2,346	1,282
Deferred income taxes	3,620	189	(2,163)
Noncash compensation related to stock plans	12,747	10,667	6,837
Gain in equity method investment			(4,389)
Excess tax benefit of options exercised	(80)	(110)
Provision for (recovery of) doubtful accounts	(48)	355	67
Accrued interest earned from related party			(58)
Changes in operating assets and liabilities, net of effects of acquisitions and dispositions:
Trade accounts receivable	(6,651)	(2,678)	(6,982)
Inventories	8,458	(17,045)	(26,196)
Other current assets	27	3,970	(190)
Other noncurrent assets	237	(244)	1,376
Trade accounts payable	(2,708)	12,208	(10,126)
Accrued liabilities	2,653	(909)	2,899
Accrued profit sharing trust contributions	617	703	(1,102)
Accrued cash profit sharing and commissions	2,611	(54)	673
Other long-term liabilities	(1,024)	(1,433)	(1,112)
Accrued workers' compensation	(100)	(783)	790
Income taxes payable	4,595	(8,874)	545
Net cash provided by operating activities	106,506	68,052	35,087
Cash flows from investing activities
Capital expenditures	(16,804)	(21,961)	(26,063)
Asset acquisitions, net of cash acquired	(6,493)	(65,125)	(51,853)
Loan repayments by related parties	700	1,698	552
Proceeds from sale of assets and a business	5,262	7,642	3,081
Net cash used in investing activities	(17,335)	(77,746)	(74,283)
Cash flows from financing activities
Line of credit and other borrowings		2,183
Repayment of line of credit and other borrowings	(81)	(5,747)
Debt issuance costs		(1,415)
Contingent consideration of asset acquisitions	(520)	(354)
Repurchase of common stock	(9,825)		(53,208)
Issuance of Company's common stock	15,057	4,925	214
Excess tax benefit of options exercised	80	110
Dividends paid	(18,130)	(30,193)	(23,329)
Net cash used in financing activities	(13,419)	(30,491)	(76,323)
Effect of exchange rate changes on cash	(97)	1,921	(5,713)
Net increase (decrease) in cash and cash equivalents	75,655	(38,264)	(121,232)
Cash and cash equivalents at beginning of year	175,553	213,817	335,049
Cash and cash equivalents at end of year	251,208	175,553	213,817
Cash paid during the year for
Interest	30	350	279
Income taxes	23,624	31,391	30,789
Noncash activity during the year for
Capital expenditures	1,082	974	402
Asset acquisition	806	786	363
Stock-based compensation	318	418	204
Dividends declared but not paid	6,095	6,053	6,020
Equity method investment acquisition (Note 6)			708
Contribution in excess of pension benefit cost	$ 55	$ 57