CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	$ 44,650	$ 48,748
Adjustments to reconcile net earnings to net cash used in operating activities:
Depreciation and amortization	13,933	14,364
Deferred income taxes	(443)	153
Amortization of marketable security premiums	1,351	1,840
Changes in operating assets and liabilities:
Accounts receivable	(45,881)	(51,270)
Other receivables	(649)	(4,265)
Inventories	(8,333)	(10,018)
Prepaid expenses and other assets	8,268	3,313
Accounts payable and accrued liabilities	10,932	8,249
Income taxes payable	15,821	8,706
Postretirement health care benefits	(720)	(677)
Deferred compensation and other liabilities	2,051	(723)
Net cash from operating activities	40,980	18,420
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(16,812)	(11,699)
Purchases of trading securities	(3,807)	(3,387)
Sales of trading securities	817	3,544
Purchase of available for sale securities	(65,098)	(51,935)
Sale and maturity of available for sale securities	45,379	21,328
Net cash used in investing activities	(39,521)	(42,149)
CASH FLOWS FROM FINANCING ACTIVITIES:
Shares purchased and retired	(16,650)	(30,027)
Dividends paid in cash	(17,208)	(16,965)
Proceeds from bank loans	1,264	1,182
Repayment of bank loans	(1,506)	(1,345)
Net cash used in financing activities	(34,100)	(47,155)
Effect of exchange rate changes on cash	647	1,269
Decrease in cash and cash equivalents	(31,994)	(69,615)
Cash, cash equivalents, and restricted cash at beginning of year	96,720	119,527
Cash, cash equivalents, and restricted cash at end of quarter	64,726	49,912
Supplemental cash flow information:
Income taxes paid/(received), net	(2,811)	12,360
Interest paid	81	49
Stock dividend issued	$ 60,538	$ 69,739