Condensed Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock
Beginning balance at Jul. 31, 2016	$ 470,401,000	$ 3,837,000	$ 524,797,000	$ 383,616,000	$ (441,849,000)
Common stock, beginning balance (in shares) at Jul. 31, 2016		38,367,997
Treasury stock, beginning balance (in shares) at Jul. 31, 2016					15,033,317
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-classified stock award compensation	970,000		970,000
Proceeds from issuance of employee stock purchase plan shares	183,000	$ 2,000	181,000
Proceeds from issuance of employee stock purchase plan shares (in shares)		16,812
Issuance of restricted stock	0	$ 14,000	(14,000)
Issuance of restricted stock (in shares)		144,899
Net settlement of stock-based awards	(163,000)	$ 3,000	(166,000)
Net settlement of stock-based awards (in shares)		25,697
Cash dividends declared	(7,008,000)			(7,008,000)
Accrual of dividend equivalents	(129,000)			(129,000)
Net income tax shortfall from settlement of stock-based awards	(161,000)		(161,000)
Reversal of deferred tax assets associated with expired and unexercised stock-based awards	(316,000)		(316,000)
Net loss	(2,489,000)			(2,489,000)
Ending balance at Oct. 31, 2016	461,288,000	$ 3,856,000	525,291,000	373,990,000	$ (441,849,000)
Common stock, ending balance (in shares) at Oct. 31, 2016		38,555,405
Treasury stock, ending balance (in shares) at Oct. 31, 2016					15,033,317
Beginning balance at Jul. 31, 2017	$ 480,150,000	$ 3,862,000	533,001,000	385,136,000	$ (441,849,000)
Common stock, beginning balance (in shares) at Jul. 31, 2017	38,619,467	38,619,467
Treasury stock, beginning balance (in shares) at Jul. 31, 2017	15,033,317				15,033,317
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-classified stock award compensation	$ 747,000		747,000
Proceeds from issuance of employee stock purchase plan shares	189,000	$ 1,000	188,000
Proceeds from issuance of employee stock purchase plan shares (in shares)		11,674
Forfeiture of restricted stock	0	$ (1,000)	1,000
Forfeiture of restricted stock (in shares)		(10,254)
Net settlement of stock-based awards	(995,000)	$ 2,000	(997,000)
Net settlement of stock-based awards (in shares)		19,624
Cash dividends declared	(2,351,000)			(2,351,000)
Accrual of dividend equivalents	(61,000)			(61,000)
Net loss	(1,660,000)			(1,660,000)
Ending balance at Oct. 31, 2017	$ 476,019,000	$ 3,864,000	$ 532,940,000	$ 381,064,000	$ (441,849,000)
Common stock, ending balance (in shares) at Oct. 31, 2017	38,640,511	38,640,511
Treasury stock, ending balance (in shares) at Oct. 31, 2017	15,033,317				15,033,317