Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Cash Flows from Operating Activities
Net Income	$ 10,792	$ 13,613	$ 11,368
Adjustments to reconcile net income to net cash provided by operating activites:
Depreciation and amortization	12,772	12,192	11,994
Amortization of investment discounts	(47)	(10)	(1)
Non-cash stock compensation expense	1,507	1,247	1,142
Excess tax benefits for share-based payments	(424)	(194)	(77)
Deferred income taxes	2,408	(8,114)	(2,450)
Provision for bad debts and cash discounts	(13)	50	177
Loss on the sale of property, plant and equipment	326	331	191
Gain on sale of marketable securities	0	0	(105)
Life insurance benefits	0	0	(117)
(Increase) decrease in:
Accounts receivable	(2,331)	942	(646)
Inventories	666	(1,954)	3,114
Prepaid expenses	(1,248)	167	2,455
Other assets	(694)	(3)	(1,287)
Increase (decrease) in:
Accounts payable	2,423	(931)	571
Accrued expenses	(845)	2,746	(697)
Deferred compensation	1,033	986	251
Pension and postretirement benefits	209	4,171	814
Other liabilities	415	(68)	279
Total Adjustments	16,157	11,558	15,608
Net Cash Provided by Operating Activities	26,949	25,171	26,976
Cash Flows from Investing Activities
Capital expenditures	(14,763)	(10,684)	(15,859)
Proceeds from sale of property, plant and equipment	64	261	22
Increase (Decrease) in Restricted Cash	0	0	(129)
Purchases of short-term investments	(47,531)	(45,198)	(2,890)
Dispositions of short-term investments	34,186	37,214	3,341
Proceeds from sale of marketable securities	0	0	108
Proceeds from life insurance	0	0	903
Net Cash Used in Investing Activities	(28,044)	(18,407)	(14,246)
Cash Flows from Financing Activities
Principal payments on notes payable	(3,083)	(3,484)	(3,500)
Dividends paid	(5,926)	(5,600)	(5,247)
Purchase of treasury stock	(135)	(18)	(122)
Proceeds from issuance of treasury stock	0	370	0
Proceeds from issuance of common stock	170	96	49
Excess tax benefits for share-based payments	424	194	77
Net Cash Used in Financing Activities	(8,550)	(8,442)	(8,743)
Effect of exchange rate changes on cash and cash equivalents	111	169	(79)
Net (Decrease) Increase in Cash and Cash Equivalents	(9,534)	(1,509)	3,908
Cash and Cash Equivalents, Beginning of Year	18,629	20,138	16,230
Cash and Cash Equivalents, End of Year	9,095	18,629	20,138
Cash paid for:
Interest, net of amounts capitalized	484	622	826
Income taxes	3,176	6,693	2,339
Noncash investing and financing activities:
Capital expenditures accrued, but not paid	1,557	761	223
Cash dividends declared and accrued, but not paid	$ 1,553	$ 1,477	$ 1,376