Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net earnings	$ 18,783	$ 19,346
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	10,836	11,127
Stock compensation expense	1,631	1,793
Deferred income taxes	35	(38)
Provision for (recovery of) doubtful accounts	88	(69)
Foreign currency transaction loss	50	51
Asset impairment charge	114	71
Gain on disposal of assets	(2,719)	(1,093)
Changes in assets and liabilities
Accounts receivable	(912)	(4,340)
Inventories	(139)	(5,442)
Prepaid expenses and other current assets	972	345
Accounts payable and accrued expenses	(12,389)	(2,273)
Income taxes	6,575	5,633
Other	(442)	368
Net cash provided by operating activities	22,483	25,479
Cash flows from investing activities:
Capital expenditures	(8,488)	(3,735)
Proceeds from insurance	2,727	1,590
Intangible assets acquired	(19)	(119)
Net cash used in investing activities	(5,780)	(2,264)
Cash flows from financing activities:
Principal payments on revolving loan	(16,000)	0
Principal payments on long-term debt	0	(8,750)
Proceeds from stock options exercised	288	1,261
Dividends paid	(15,135)	(13,421)
Purchase of treasury stock	(727)	(786)
Net cash used in financing activities	(31,574)	(21,696)
Effect of exchange rate changes on cash	(393)	744
(Decrease) increase in cash and cash equivalents	(15,264)	2,263
Cash and cash equivalents beginning of period	54,268	40,416
Cash and cash equivalents end of period	$ 39,004	$ 42,679