CONSOLIDATED STATEMENTS OF Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	$ 48,748	$ 49,527
Adjustments to reconcile net earnings to net cash used in operating activities:
Depreciation and amortization	14,364	14,651
Deferred income taxes	153	23
Amortization of marketable security premiums	1,840	2,221
Changes in operating assets and liabilities:
Accounts receivable	(51,270)	(31,367)
Other receivables	(4,265)	2,622
Inventories	(10,018)	(2,826)
Prepaid expenses and other assets	3,313	3,678
Accounts payable and accrued liabilities	8,249	6,906
Income taxes payable	8,706	3
Postretirement health care benefits	(677)	(902)
Deferred compensation and other liabilities	(723)	2,496
Net cash from operating activities	18,420	47,032
CASH FLOWS FROM INVESTING ACTIVITIES:
Restricted cash	(17)
Capital expenditures	(11,699)	(13,067)
Purchases of trading securities	(3,387)	(3,064)
Sales of trading securities	3,544	645
Purchase of available for sale securities	(51,935)	(45,298)
Sale and maturity of available for sale securities	21,328	26,517
Net cash used in investing activities	(42,166)	(34,267)
CASH FLOWS FROM FINANCING ACTIVITIES:
Shares purchased and retired	(30,027)	(26,293)
Dividends paid in cash	(16,965)	(16,694)
Proceeds from bank loans	1,182	2,156
Repayment of bank loans	(1,345)	(2,339)
Net cash used in financing activities	(47,155)	(43,170)
Effect of exchange rate changes on cash	1,268	(1,501)
Decrease in cash and cash equivalents	(69,633)	(31,906)
Cash and cash equivalents at beginning of year	119,145	126,145
Cash and cash equivalents at end of year	49,512	94,239
Supplemental cash flow information:
Income taxes paid	12,360	22,622
Interest paid	49	19
Stock dividend issued	$ 69,739	$ 61,671