Fair Value Measurements - Hierarchy Levels (Details) - Recurring basis - USD ($) $ in Thousands		Jul. 31, 2017	Jul. 31, 2016
Assets:
Total assets		$ 102	$ 740
Liabilities:
Total liabilities		127,138	117,579
Accrued expenses:
Liabilities:
Assumed contingent obligation		12	12
Contingent guaranteed obligation		0	366
Total accrued expenses		12	378
Long-term debt	[1]	126,000	116,000
Other long-term liabilities:
Liabilities:
Contingent consideration			0
Assumed contingent obligation		1,126	1,126
Contingent guaranteed obligation		0	75
Total other long-term liabilities:		1,126	1,201
Money markets | Cash and cash equivalents:
Assets:
Money markets		102	740
Level 1
Assets:
Total assets		102	740
Liabilities:
Total liabilities		0	0
Level 1 | Accrued expenses:
Liabilities:
Assumed contingent obligation		0	0
Contingent guaranteed obligation		0	0
Total accrued expenses		0	0
Long-term debt	[1]	0	0
Level 1 | Other long-term liabilities:
Liabilities:
Contingent consideration			0
Assumed contingent obligation		0	0
Contingent guaranteed obligation		0	0
Total other long-term liabilities:		0	0
Level 1 | Money markets | Cash and cash equivalents:
Assets:
Money markets		102	740
Level 2
Assets:
Total assets		0	0
Liabilities:
Total liabilities		126,000	116,000
Level 2 | Accrued expenses:
Liabilities:
Assumed contingent obligation		0	0
Contingent guaranteed obligation		0	0
Total accrued expenses		0	0
Long-term debt		126,000	116,000
Level 2 | Other long-term liabilities:
Liabilities:
Contingent consideration			0
Assumed contingent obligation		0	0
Contingent guaranteed obligation		0	0
Total other long-term liabilities:		0	0
Level 2 | Money markets | Cash and cash equivalents:
Assets:
Money markets		0	0
Level 3
Assets:
Total assets		0	0
Liabilities:
Total liabilities		1,138	1,579
Level 3 | Accrued expenses:
Liabilities:
Assumed contingent obligation		12	12
Contingent guaranteed obligation		0	366
Total accrued expenses		12	378
Long-term debt	[1]	0	0
Level 3 | Other long-term liabilities:
Liabilities:
Contingent consideration			0
Assumed contingent obligation		1,126	1,126
Contingent guaranteed obligation		0	75
Total other long-term liabilities:		1,126	1,201
Level 3 | Money markets | Cash and cash equivalents:
Assets:
Money markets		$ 0	$ 0

[1] Fair value estimated using Level 2 inputs, which were quoted prices for identical or similar instruments in markets that are not active.