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	$ 58,974	$ 64,839	$ 56,805
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation	18,184	18,779	18,669
Deferred income taxes	(279)	2,832	2,063
Impairment of majority-owned foreign subsidiaries		377	1,126
Amortization of marketable security premiums	1,404	1,282	1,755
Changes in operating assets and liabilities:
Accounts receivable	3,483	5,086	(2,445)
Other receivables	636	(313)	2,220
Inventories	(770)	(4,383)	303
Prepaid expenses and other assets	2,961	4,362	9,489
Accounts payable and accrued liabilities	3,849	1,080	1,648
Income taxes payable	3,012	4,336	7,953
Postretirement health care benefits	(1,041)	(1,478)	(2,484)
Deferred compensation and other liabilities	(15,703)	3,422	3,827
Net cash provided by operating activities	74,710	100,221	100,929
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(17,970)	(20,258)	(27,612)
Repayment of premiums on split dollar life insurance policies	23,527
Purchases of trading securities	(3,183)	(3,427)	(4,378)
Sales of trading securities	18,058	795	1,255
Purchase of available for sale securities	(109,816)	(67,730)	(78,377)
Sale and maturity of available for sale securities	98,885	75,611	64,602
Net cash used in investing activities	9,501	(15,009)	(44,510)
CASH FLOWS FROM FINANCING ACTIVITIES:
Shares purchased and retired	(32,055)	(34,116)	(19,317)
Dividends paid in cash	(23,810)	(23,460)	(22,978)
Proceeds from bank loans	3,902	3,582	2,491
Repayment of bank loans	(3,883)	(3,193)	(2,549)
Net cash used in financing activities	(55,846)	(57,187)	(42,353)
Effect of exchange rate changes on cash	(449)	28	501
Increase (decrease) in cash and cash equivalents	27,916	28,053	14,567
Cash, cash equivalents and restricted cash at beginning of year	139,340	111,287	96,720
Cash, cash equivalents and restricted cash at end of year	167,256	139,340	111,287
Supplemental cash flow information:
Income taxes paid	14,503	13,858	5,676
Interest paid	57	121	112
Stock dividend issued	$ 63,402	$ 70,557	$ 60,538