CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income
Beginning balance (in shares) at Jul. 31, 2018		60,742,859
Beginning balance at Jul. 31, 2018	$ 107,628	$ 608	$ 7,467,855	$ (7,363,569)	$ 2,734
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(19,118)			(19,118)
Effect of adoption of ASC 606 on August 1, 2018, net of taxes	6,138
Preferred dividends	(1,073)			(1,073)
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises (in shares)		9,405
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises	13		13
Restricted stock grants (in shares)		1,045,543
Restricted stock grants		$ 10	(10)
Share-based compensation	770		770
Other comprehensive items	179				179
Ending balance (in shares) at Jan. 31, 2019		61,797,807.000
Ending balance at Jan. 31, 2019	94,537	$ 618	7,468,628	(7,377,622)	2,913
Beginning balance (in shares) at Oct. 31, 2018		61,386,888
Beginning balance at Oct. 31, 2018	105,433	$ 614	7,468,647	(7,365,332)	1,504
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(11,753)			(11,753)
Preferred dividends	(537)
Preferred dividends	(536)
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises (in shares)		6,298
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises	7		7
Restricted stock grants (in shares)		404,621
Restricted stock grants	0	$ 4	(4)
Share-based compensation	(22)		(22)
Other comprehensive items	1,409				1,409
Ending balance (in shares) at Jan. 31, 2019		61,797,807.000
Ending balance at Jan. 31, 2019	$ 94,537	$ 618	7,468,628	(7,377,622)	2,913
Beginning balance (in shares) at Jul. 31, 2019	61,805,856	61,805,856
Beginning balance at Jul. 31, 2019	$ 52,692	$ 618	7,477,327	(7,426,287)	1,034
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,235			1,235
Preferred dividends	(1,067)			(1,067)
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises (in shares)		9,179
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises	4		4
Restricted stock grants (in shares)		560,523
Restricted stock grants		$ 6	(6)
Share-based compensation	372		372
Other comprehensive items	$ 579				579
Ending balance (in shares) at Jan. 31, 2020	62,375,558	62,375,558
Ending balance at Jan. 31, 2020	$ 53,815	$ 624	7,477,697	(7,426,119)	1,613
Beginning balance (in shares) at Oct. 31, 2019		61,810,253
Beginning balance at Oct. 31, 2019	57,137	$ 618	7,477,505	(7,422,031)	1,045
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(3,557)			(3,557)
Preferred dividends	(531)			(531)
Preferred dividends	(531)
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises (in shares)		4,782
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises	2		2
Restricted stock grants (in shares)		560,523
Restricted stock grants		$ 6	(6)
Share-based compensation	196		196
Other comprehensive items	$ 568				568
Ending balance (in shares) at Jan. 31, 2020	62,375,558	62,375,558
Ending balance at Jan. 31, 2020	$ 53,815	$ 624	$ 7,477,697	$ (7,426,119)	$ 1,613