Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities
Net income	$ 53,151	$ 43,303
Adjustments to reconcile net income to net cash provided by operating activities:
(Gain) loss on sale of assets	(336)	634
Depreciation and amortization	22,105	21,631
Impairment loss on assets	492	1,025
Gain on contingent consideration adjustment	386	0
Deferred income taxes	1,324	2,336
Noncash compensation related to stock plans	9,508	9,106
Excess tax benefit of options exercised and restricted stock units vested	(66)	(42)
Provision for doubtful accounts	25	342
Changes in operating assets and liabilities, net of acquisitions:
Trade accounts receivable	(39,357)	(36,296)
Inventories	(3,235)	17,643
Trade accounts payable	(9,121)	(4,543)
Income taxes payable	5,652	9,372
Accrued profit sharing trust contributions	(1,103)	(606)
Accrued cash profit sharing and commissions	7,743	9,053
Other current assets	(2,307)	(1,218)
Accrued liabilities	3,102	(112)
Long-term liabilities	2,728	(1,563)
Accrued workers’ compensation	(159)	503
Other noncurrent assets	(603)	1,352
Net cash provided by operating activities	49,157	71,920
Cash flows from investing activities
Capital expenditures	(17,517)	(12,949)
Asset acquisitions, net of cash acquired	0	(5,300)
Proceeds from sale of property and equipment	612	1,823
Loan made to customer	(281)	0
Loan repayment by customer	22	0
Loan repayment by related party	0	625
Net cash used in investing activities	(17,164)	(15,801)
Cash flows from financing activities
Deferred and contingent consideration paid for asset acquisition	1,293	0
Repurchase of common stock	(2,981)	(9,825)
Debt and line of credit borrowings	0	1,378
Repayment of debt and line of credit borrowings	(60)	(609)
Issuance of common stock	4,178	5,333
Excess tax benefit of options exercised and restricted stock units vested	66	42
Dividends paid	(19,065)	(12,081)
Net cash used in financing activities	(19,155)	(15,762)
Effect of exchange rate changes on cash and cash equivalents	(5,808)	(146)
Net increase in cash and cash equivalents	7,030	40,211
Cash and cash equivalents at beginning of period	251,208	175,553
Cash and cash equivalents at end of period	258,238	215,764
Noncash activity during the period
Noncash capital expenditures	501	670
Dividends declared but not paid	6,862	6,015
Issuance of Company’s common stock for compensation	$ 402	$ 318