Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Jul. 31, 2017
Deferred tax assets:
Accrued expenses	$ 5,354	$ 6,308
Inventories	3,165	4,655
Accounts receivable	306	729
Other long-term liabilities	103	180
Stock-based compensation	2,700	3,402
Capital investment	426	545
Foreign NOLs	8,605	6,490
Subtotal	20,659	22,309
Valuation allowance	(6,358)	(2,984)
Deferred tax assets, net of valuation allowance	14,301	19,325
Deferred tax liabilities:
Property and equipment	(7,352)	(9,957)
Intangible assets	(21,300)	(20,107)
Goodwill	(10,362)	(13,975)
Deferred tax liabilities, gross	(39,014)	(44,039)
Deferred income taxes (assets)	2,911	0
Deferred income taxes (liabilities)	(27,624)	(24,714)
Net deferred income taxes	$ (24,713)	$ (24,714)