Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities
Net income	$ 23,297	$ 23,060
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on sale of assets	3	10
Depreciation and amortization	14,777	13,813
Impairment loss on assets	1,025	461
Deferred income taxes	1,281	(681)
Noncash compensation related to stock plans	6,001	5,300
Excess tax benefit of options exercised	(11)	(99)
Provision for doubtful accounts	9	225
Changes in operating assets and liabilities, net of acquisitions:
Trade accounts receivable	(45,345)	(40,837)
Inventories	7,168	(47)
Trade accounts payable	(7,021)	10,694
Income taxes payable	11,859	4,462
Accrued profit sharing trust contributions	(1,944)	(2,085)
Accrued cash profit sharing and commissions	8,624	6,873
Other current assets	185	3,537
Accrued liabilities	(1,502)	(4,775)
Long-term liabilities	(477)	(250)
Accrued workers' compensation	403	(613)
Other noncurrent assets	578	(2,168)
Net cash provided by operating activities	18,910	16,880
Cash flows from investing activities
Capital expenditures	(8,095)	(9,629)
Asset acquisitions, net of cash acquired	(5,300)	(56,044)
Proceeds from sale of property and equipment	110	6,958
Loan repayment by related parties	625
Net cash used in investing activities	(12,660)	(58,715)
Cash flows from financing activities
Repurchase of common stock	(9,825)
Debt and line of credit borrowings	1,129	2,146
Repayment of debt and line of credit borrowings	(86)	(954)
Debt issuance costs		(25)
Issuance of common stock	776	1,983
Excess tax benefit of options exercised	11	99
Dividends paid	(6,053)	(12,059)
Net cash used in financing activities	(14,048)	(8,810)
Effect of exchange rate changes on cash and cash equivalents	(2,480)	(453)
Net decrease in cash and cash equivalents	(10,278)	(51,098)
Cash and cash equivalents at beginning of period	175,553	213,817
Cash and cash equivalents at end of period	165,275	162,719
Noncash activity during the period
Noncash capital expenditures	63	258
Dividends declared but not paid	6,068	6,044
Issuance of Company's common stock for compensation	318	418
Non-cash contingent consideration		$ 786