Fair Value Measurements - Hierarchy Levels (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jul. 31, 2018
Recurring basis
Assets:
Total assets	$ 3,416	$ 104
Liabilities:
Contingent consideration	1,411	1,298
Total liabilities	1,411	1,298
Recurring basis | Money markets
Assets:
Money markets	104	104
Recurring basis | Level 1
Assets:
Total assets	104	104
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Recurring basis | Level 1 | Money markets
Assets:
Money markets	104	104
Recurring basis | Level 2
Assets:
Total assets	3,312	0
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Recurring basis | Level 2 | Money markets
Assets:
Money markets	0	0
Recurring basis | Level 3
Assets:
Total assets	0	0
Liabilities:
Contingent consideration	1,411	1,298
Total liabilities	1,411	1,298
Recurring basis | Level 3 | Money markets
Assets:
Money markets	0	$ 0
Interest Rate Swap
Assets:
Derivative asset, short term	486
Derivative asset, long term	2,826
Interest Rate Swap | Recurring basis
Assets:
Derivative asset, short term	486
Derivative asset, long term	2,826
Interest Rate Swap | Recurring basis | Level 1
Assets:
Derivative asset, short term	0
Derivative asset, long term	0
Interest Rate Swap | Recurring basis | Level 2
Assets:
Derivative asset, short term	486
Derivative asset, long term	2,826
Interest Rate Swap | Recurring basis | Level 3
Assets:
Derivative asset, short term	0
Derivative asset, long term	$ 0