Fair Value Measurements - Hierarchy Levels (Details) - USD ($) $ in Thousands	Apr. 30, 2020	Jul. 31, 2019
Current portion of long-term debt:
Financing component of interest rate swap	$ 31,414	$ 10,000
Long-term debt:
Long-term debt	944,011	220,851
Recurring basis
Other Assets:
Total assets	107	3,416
Accrued expenses:
Contingent consideration	1,638
Other long-term liabilities:
Contingent consideration		1,411
Total liabilities	21,537	1,411
Recurring basis | Money markets
Cash and cash equivalents:
Money markets	107	104
Recurring basis | Level 1
Other Assets:
Total assets	107	104
Accrued expenses:
Contingent consideration	0
Other long-term liabilities:
Contingent consideration		0
Total liabilities	0	0
Recurring basis | Level 1 | Money markets
Cash and cash equivalents:
Money markets	107	104
Recurring basis | Level 2
Other Assets:
Total assets	0	3,312
Accrued expenses:
Contingent consideration	0
Other long-term liabilities:
Contingent consideration		0
Total liabilities	19,899	0
Recurring basis | Level 2 | Money markets
Cash and cash equivalents:
Money markets	0	0
Recurring basis | Level 3
Other Assets:
Total assets	0	0
Accrued expenses:
Contingent consideration	1,638
Other long-term liabilities:
Contingent consideration		1,411
Total liabilities	1,638	1,411
Recurring basis | Level 3 | Money markets
Cash and cash equivalents:
Money markets	0	0
Interest rate swap | Recurring basis
Prepaid and other current assets:
Interest rate swap		486
Other Assets:
Interest rate swap		2,826
Current portion of long-term debt:
Financing component of interest rate swap	1,914
Accrued expenses:
Interest rate swap	3,483
Long-term debt:
Long-term debt	6,381
Other long-term liabilities:
Interest rate swap	8,121
Interest rate swap | Recurring basis | Level 1
Prepaid and other current assets:
Interest rate swap		0
Other Assets:
Interest rate swap		0
Current portion of long-term debt:
Financing component of interest rate swap	0
Accrued expenses:
Interest rate swap	0
Long-term debt:
Long-term debt	0
Other long-term liabilities:
Interest rate swap	0
Interest rate swap | Recurring basis | Level 2
Prepaid and other current assets:
Interest rate swap		486
Other Assets:
Interest rate swap		2,826
Current portion of long-term debt:
Financing component of interest rate swap	1,914
Accrued expenses:
Interest rate swap	3,483
Long-term debt:
Long-term debt	6,381
Other long-term liabilities:
Interest rate swap	8,121
Interest rate swap | Recurring basis | Level 3
Prepaid and other current assets:
Interest rate swap		0
Other Assets:
Interest rate swap		$ 0
Current portion of long-term debt:
Financing component of interest rate swap	0
Accrued expenses:
Interest rate swap	0
Long-term debt:
Long-term debt	0
Other long-term liabilities:
Interest rate swap	$ 0