Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net earnings	$ 84,623	$ 79,671	$ 78,573
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	51,281	45,862	44,666
Stock compensation expense	8,303	7,596	6,413
Deferred income taxes	(4,627)	(3,563)	(5,403)
Provision for doubtful accounts	140	1,776	43
Unrealized loss/(gain) on foreign currency transactions and deferred compensation	173	72	(141)
Asset impairment charge	1,915	1,140	1,801
Loss/(Gain) on disposal of assets	153	(3,134)	(3,244)
Changes in assets and liabilities, net of acquired balances
Accounts receivable	(3,599)	11,623	(7,773)
Inventories	13,923	(11,401)	(6,016)
Prepaid expenses and other current assets	(2,856)	477	1,517
Accounts payable and accrued expenses	(992)	1,134	5,988
Income taxes	1,859	(5,664)	1,121
Other	198	(1,128)	1,152
Net cash provided by operating activities	150,494	124,461	118,697
Cash flows from investing activities:
Capital expenditures and intangible assets acquired	(33,828)	(28,413)	(19,723)
Cash paid for acquisitions, net of cash acquired	0	(141,062)	(17,399)
Proceeds from sale of business and assets	87	11,523	966
Proceeds from insurance	0	2,727	4,165
Purchase of convertible notes	(850)	(1,000)	0
Net cash used in investing activities	(34,591)	(156,225)	(31,991)
Cash flows from financing activities:
Proceeds from revolving loan	10,000	168,569	210,750
Principal payments on revolving loan	(95,000)	(76,000)	(54,750)
Principal payments on finance lease	(151)	0	0
Principal payments on long-term debt	0	0	(219,500)
Principal payment on acquired debt	0	(17,567)	(19)
Cash paid for financing costs	0	0	(1,374)
Proceeds from stock options exercised	14,155	4,839	8,272
Dividends paid	(16,705)	(15,135)	(13,432)
Purchase of treasury stock	(13,463)	(21,321)	(1,394)
Net cash (used in) provided by financing activities	(101,164)	43,385	(71,447)
Effect of exchange rate changes on cash	4,160	(217)	(1,407)
Increase in cash and cash equivalents	18,899	11,404	13,852
Cash and cash equivalents beginning of period	65,672	54,268	40,416
Cash and cash equivalents end of period	$ 84,571	$ 65,672	$ 54,268