The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Topic 230
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Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2017	Jan. 31, 2016	Jul. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 1,300	$ 1,500	$ 2,600	$ 3,000
Amortized intangibles:
Accumulated amortization	(27,023)		(27,023)		$ (24,063)
Net intangibles	8,938		8,938		11,761
Covenants not to compete
Amortized intangibles:
Gross carrying amount	1,708		1,708		1,702
Supply contracts & customer relationships
Amortized intangibles:
Gross carrying amount	26,689		26,689		26,471
Trade name
Amortized intangibles:
Gross carrying amount	5,095		5,095		5,163
Licenses and databases
Amortized intangibles:
Gross carrying amount	$ 2,469		$ 2,469		$ 2,488