Consolidated Statements Of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net earnings	$ 44,564,000	$ 40,496,000	$ 26,477,000
Adjustments to reconcile net earnings to net cash provided by operating activities:
Intangibles amortization	721,000	5,173,000	11,991,000
Provision for depreciation	13,962,000	10,427,000	9,828,000
Deferred income tax provision (benefit)	6,360,000	(998,000)	(1,005,000)
Impairment of finite lived intangible assets			2,063,000
Gain on involuntary conversion of machinery and equipment	(968,000)
Loss (gain) on disposal of property, plant and equipment	434,000	70,000	(2,000)
Provision for doubtful accounts	1,000	516,000	532,000
Non-cash retirement plan expense	782,000	775,000	705,000
Other	217,000	220,000	141,000
Changes in operating accounts:
Accounts receivable, net	(13,539,000)	708,000	16,536,000
Inventories	(7,528,000)	(9,398,000)	8,144,000
Other assets and current assets	5,148,000	(2,894,000)	5,291,000
Accounts payable and accrued liabilities	12,145,000	(2,684,000)	(6,033,000)
Federal and state income taxes receivable/payable	4,077,000	3,864,000	(1,455,000)
Net cash provided by operating activities	66,376,000	46,275,000	73,213,000
Cash flows from investing activities:
Marketable securities purchased	(86,119,000)	(20,170,000)	(8,976,000)
Marketable securities - maturities and sales	33,863,000	10,306,000	22,959,000
Purchase of property, plant and equipment	(6,950,000)	(6,461,000)	(11,287,000)
Note issued	(2,419,000)
Proceeds from insurnace settlement	987,000
Acquisition of intangible assets	(211,000)
Sale of property, plant and equipment	3,000	25,000	307,000
Acquisition of businesses, net of cash acquired			(10,534,000)
Net cash used in investing activities	(60,846,000)	(16,300,000)	(7,531,000)
Cash flows from financing activities:
Dividends paid	(35,161,000)	(28,114,000)	(34,954,000)
Proceeds from sale of treasury stock	443,000	323,000	362,000
Other		(5,000)
Net cash used in financing activities	(34,718,000)	(27,796,000)	(34,592,000)
Net increase (decrease) in cash and cash equivalents	(29,188,000)	2,179,000	31,090,000
Cash and cash equivalents at beginning of year	56,222,000	54,043,000	22,953,000
Cash and cash equivalents at end of year	27,034,000	56,222,000	54,043,000
Supplemental disclosures of cash flow information:
Income taxes	$ 17,278,000	$ 21,930,000	$ 17,411,000