Fair Value Measurements - Hierarchy Levels (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Jul. 31, 2019
Recurring basis
Other assets:
Total assets	$ 106	$ 3,416
Accrued expenses:
Contingent consideration	0	1,411
Other long-term liabilities:
Total liabilities	21,156	1,411
Recurring basis | Money markets
Cash and cash equivalents:
Cash and cash equivalents	106	104
Recurring basis | Level 1
Other assets:
Total assets	106	104
Accrued expenses:
Contingent consideration	0	0
Other long-term liabilities:
Total liabilities	0	0
Recurring basis | Level 1 | Money markets
Cash and cash equivalents:
Cash and cash equivalents	106	104
Recurring basis | Level 2
Other assets:
Total assets	0	3,312
Accrued expenses:
Contingent consideration	0	0
Other long-term liabilities:
Total liabilities	21,156	0
Recurring basis | Level 2 | Money markets
Cash and cash equivalents:
Cash and cash equivalents	0	0
Recurring basis | Level 3
Other assets:
Total assets	0	0
Accrued expenses:
Contingent consideration	0	1,411
Other long-term liabilities:
Total liabilities	0	1,411
Recurring basis | Level 3 | Money markets
Cash and cash equivalents:
Cash and cash equivalents	0	0
Interest Rate Swap
Prepaid expenses and other current assets:
Interest rate swap		486
Accrued expenses:
Interest rate swap	5,462
Interest Rate Swap | Recurring basis
Prepaid expenses and other current assets:
Interest rate swap		486
Other assets:
Interest rate swap		2,826
Accrued expenses:
Interest rate swap	5,462
Other long-term liabilities:
Interest rate swap	15,694
Interest Rate Swap | Recurring basis | Level 1
Prepaid expenses and other current assets:
Interest rate swap		0
Other assets:
Interest rate swap		0
Accrued expenses:
Interest rate swap	0
Other long-term liabilities:
Interest rate swap	0
Interest Rate Swap | Recurring basis | Level 2
Prepaid expenses and other current assets:
Interest rate swap		486
Other assets:
Interest rate swap		2,826
Accrued expenses:
Interest rate swap	5,462
Other long-term liabilities:
Interest rate swap	15,694
Interest Rate Swap | Recurring basis | Level 3
Prepaid expenses and other current assets:
Interest rate swap		0
Other assets:
Interest rate swap		$ 0
Accrued expenses:
Interest rate swap	0
Other long-term liabilities:
Interest rate swap	$ 0