Shareholders' Equity, Reconciliation of Changes in Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018	Jul. 31, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance			$ 36,447
Net income (loss)	$ (310)	$ (528)	(425)	$ 160
Foreign currency translation adjustments	47	51	(80)	37
Unrealized investment losses, net	0	(13)	0	(16)
Balance	35,919		35,919
Common Stock [Member] | Class A Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	31	30	30	30
Balance (Adjusted)			30
Net income (loss)	0	0	0	0
Foreign currency translation adjustments	0	0	0	0
Conversion of Class B common stock to Class A common stock			1
Issuance of stock under stock award plan			0
Unrealized investment losses, net		0		0
Share-based compensation expense	0	0	0	0
Distributions to noncontrolling interests	0	0	0	0
Purchase of additional noncontrolling interests	0		0
Balance	31	30	31	30
Common Stock [Member] | Class A Common Stock [Member] | ASU 2016-01 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption					$ 0
Common Stock [Member] | Class B Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	13	14	14	14
Balance (Adjusted)			14
Net income (loss)	0	0	0	0
Foreign currency translation adjustments	0	0	0	0
Conversion of Class B common stock to Class A common stock			(1)
Issuance of stock under stock award plan			0
Unrealized investment losses, net		0		0
Share-based compensation expense	0	0	0	0
Distributions to noncontrolling interests	0	0	0	0
Purchase of additional noncontrolling interests	0		0
Balance	13	14	13	14
Common Stock [Member] | Class B Common Stock [Member] | ASU 2016-01 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption					0
Capital in Excess of Par Value [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	17,595	17,617	17,558	17,570
Balance (Adjusted)			17,558
Net income (loss)	0	0	0	0
Foreign currency translation adjustments	0	0	0	0
Conversion of Class B common stock to Class A common stock			0
Issuance of stock under stock award plan			4
Unrealized investment losses, net		0		0
Share-based compensation expense	34	24	67	71
Distributions to noncontrolling interests	0	0	0	0
Purchase of additional noncontrolling interests	0		0
Balance	17,629	17,641	17,629	17,641
Capital in Excess of Par Value [Member] | ASU 2016-01 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption					0
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	20,848	23,593	20,973	23,005
Balance (Adjusted)			20,968
Net income (loss)	(309)	(519)	(429)	69
Foreign currency translation adjustments	0	0	0	0
Conversion of Class B common stock to Class A common stock			0
Issuance of stock under stock award plan			0
Unrealized investment losses, net		0		0
Share-based compensation expense	0	0	0	0
Distributions to noncontrolling interests	0	0	0	0
Purchase of additional noncontrolling interests	0		0
Balance	20,539	23,074	20,539	23,074
Retained Earnings [Member] | ASU 2016-01 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption					(5)
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(1,947)	(1,806)	(1,885)	(1,795)
Balance (Adjusted)			(1,880)
Net income (loss)	0	0	0	0
Foreign currency translation adjustments	54	13	(13)	5
Conversion of Class B common stock to Class A common stock			0
Issuance of stock under stock award plan			0
Unrealized investment losses, net		(13)		(16)
Share-based compensation expense	0	0	0	0
Distributions to noncontrolling interests	0	0	0	0
Purchase of additional noncontrolling interests	0		0
Balance	(1,893)	(1,806)	(1,893)	(1,806)
Accumulated Other Comprehensive Income (Loss) [Member] | ASU 2016-01 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption					5
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(884)	(1,037)	(907)	(1,037)
Balance (Adjusted)			(907)
Net income (loss)	0	0	0	0
Foreign currency translation adjustments	0	0	0	0
Conversion of Class B common stock to Class A common stock			0
Issuance of stock under stock award plan			23
Unrealized investment losses, net		0		0
Share-based compensation expense	0	0	0	0
Distributions to noncontrolling interests	0	0	0	0
Purchase of additional noncontrolling interests	0		0
Balance	(884)	(1,037)	(884)	(1,037)
Treasury Stock [Member] | ASU 2016-01 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption					0
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	605	992	664	947
Balance (Adjusted)			664
Net income (loss)	(1)	(9)	4	91
Foreign currency translation adjustments	(7)	38	(67)	32
Conversion of Class B common stock to Class A common stock			0
Issuance of stock under stock award plan			0
Unrealized investment losses, net		0		0
Share-based compensation expense	0	0	0	0
Distributions to noncontrolling interests	(112)	(143)	(116)	(192)
Purchase of additional noncontrolling interests	(1)		(1)
Balance	$ 484	$ 878	$ 484	$ 878
Noncontrolling Interest [Member] | ASU 2016-01 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption					$ 0