Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Cash Flows from Operating Activities
Net Income	$ 13,613	$ 11,368	$ 8,356
Adjustments to reconcile net income to net cash provided by operating activites:
Depreciation and amortization	12,192	11,994	10,396
Amortization of investment discounts	(10)	(1)	(2)
Non-cash stock compensation expense	1,247	1,142	1,189
Excess tax benefits for share-based payments	(194)	(77)	(86)
Deferred income taxes	(8,114)	(2,450)	284
Provision for bad debts and cash discounts	50	177	69
Loss on the sale of property, plant and equipment	331	191	452
Gain on sale of marketable securities	0	(105)	0
Life insurance benefits	0	(117)	0
(Increase) decrease in:
Accounts receivable	942	(646)	82
Inventories	(1,954)	3,114	(2,966)
Prepaid expenses	167	2,455	(1,988)
Other assets	(3)	(1,287)	(817)
Increase (decrease) in:
Accounts payable	(931)	571	187
Accrued expenses	2,746	(697)	(2,586)
Deferred compensation	986	251	698
Pension and postretirement benefits	4,171	814	2,887
Other liabilities	(68)	279	141
Total Adjustments	11,558	15,608	7,940
Net Cash Provided by Operating Activities	25,171	26,976	16,296
Cash Flows from Investing Activities
Capital expenditures	(10,684)	(15,859)	(18,566)
Proceeds from sale of property, plant and equipment	261	22	180
Acquisition of business	0	0	(12,876)
Restricted cash	0	129	(129)
Purchases of short-term investments	(45,198)	(2,890)	(10,391)
Dispositions of short-term investments	37,214	3,341	26,212
Proceeds from sale of marketable securities	0	108	0
Proceeds from life insurance	0	903	0
Net Cash Used in Investing Activities	(18,407)	(14,246)	(15,570)
Cash Flows from Financing Activities
Principal payments on notes payable	(3,484)	(3,500)	(3,500)
Dividends paid	(5,600)	(5,247)	(4,965)
Purchase of treasury stock	(18)	(122)	(87)
Proceeds from issuance of treasury stock	370	0	82
Proceeds from issuance of common stock	96	49	12
Excess tax benefits for share-based payments	194	77	86
Net Cash Used in Financing Activities	(8,442)	(8,743)	(8,372)
Effect of exchange rate changes on cash and cash equivalents	169	(79)	(159)
Net (Decrease) Increase in Cash and Cash Equivalents	(1,509)	3,908	(7,805)
Cash and Cash Equivalents, Beginning of Year	20,138	16,230	24,035
Cash and Cash Equivalents, End of Year	18,629	20,138	16,230
Cash paid for:
Interest, net of amounts capitalized	622	826	1,078
Income taxes	6,693	2,339	3,022
Noncash investing and financing activities:
Capital expenditures accrued, but not paid	761	223	712
Cash dividends declared and accrued, but not paid	$ 1,477	$ 1,376	$ 1,311