Fair Value Measurements - Hierarchy Levels (Details) - Recurring basis - USD ($) $ in Thousands	Apr. 30, 2019	Jul. 31, 2018
Assets:
Total assets	$ 855	$ 104
Other long-term liabilities:
Contingent consideration	1,374	1,298
Total liabilities	1,516	1,298
Money markets
Assets:
Money markets	104	104
Level 1
Assets:
Total assets	104	104
Other long-term liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Level 1 | Money markets
Assets:
Money markets	104	104
Level 2
Assets:
Total assets	751	0
Other long-term liabilities:
Contingent consideration	0	0
Total liabilities	142	0
Level 2 | Money markets
Assets:
Money markets	0	0
Level 3
Assets:
Total assets	0	0
Other long-term liabilities:
Contingent consideration	1,374	1,298
Total liabilities	1,374	1,298
Level 3 | Money markets
Assets:
Money markets	0	$ 0
Interest rate swap
Assets:
Interest rate swap	751
Liabilities:
Accrued expenses:	142
Interest rate swap | Level 1
Assets:
Interest rate swap	0
Liabilities:
Accrued expenses:	0
Interest rate swap | Level 2
Assets:
Interest rate swap	751
Liabilities:
Accrued expenses:	142
Interest rate swap | Level 3
Assets:
Interest rate swap	0
Liabilities:
Accrued expenses:	$ 0