Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Jul. 31, 2016
Deferred tax assets:
Accrued expenses	$ 6,308	$ 5,140
Inventories	4,655	2,990
Accounts receivable	729	793
Other long-term liabilities	180	252
Stock-based compensation	3,402	3,665
Capital investment	545	546
Foreign NOLs	6,490	5,154
Subtotal	22,309	18,540
Valuation allowance	(2,984)	(2,334)
Deferred tax assets, net of valuation allowance	19,325	16,206
Deferred tax liabilities:
Property and equipment	(9,957)	(8,089)
Intangible assets	(20,107)	(19,818)
Goodwill	(13,975)	(11,878)
Deferred tax liabilities, gross	(44,039)	(39,785)
Net deferred tax liabilities - noncurrent	$ (24,714)	$ (23,579)