Segment Information (Details) - USD ($)	3 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Jul. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 170,267,000	$ 160,844,000
Operating income (loss)	9,260,000	7,293,000
Net income (loss)	6,388,000	3,468,000
Provision for (benefit from) income taxes	1,145,000	(2,127,000)
Interest (income) and other expense	(77,000)	66,000
Write-off of deferred financing costs	0	3,217,000
Interest expense	1,804,000	2,669,000
Amortization of stock-based compensation	879,000	1,046,000
Amortization of intangibles	5,206,000	4,289,000
Depreciation	2,651,000	2,851,000
Estimated contract settlement costs	230,000	0
Facility exit costs		1,373,000
Adjusted EBITDA	20,615,000	17,982,000
Purchases of property, plant and equipment	1,250,000	1,645,000
Total assets	931,022,000	866,940,000	$ 887,711,000
Acquisition plan expenses	2,389,000	1,130,000
Unallocated
Segment Reporting Information [Line Items]
Net sales	0	0
Operating income (loss)	(7,664,000)	(6,409,000)
Net income (loss)	(10,574,000)	(10,112,000)
Provision for (benefit from) income taxes	1,132,000	(2,139,000)
Interest (income) and other expense	(17,000)	(19,000)
Write-off of deferred financing costs		3,217,000
Interest expense	1,795,000	2,644,000
Amortization of stock-based compensation		1,046,000
Amortization of intangibles	0	0
Depreciation	142,000	244,000
Estimated contract settlement costs	0
Facility exit costs		0
Adjusted EBITDA	(4,254,000)	(3,989,000)
Purchases of property, plant and equipment	26,000	124,000
Total assets	44,553,000	41,786,000
Acquisition plan expenses	2,389,000	1,130,000
Commercial Solutions Segment
Segment Reporting Information [Line Items]
Net sales	94,314,000	77,973,000
Commercial Solutions Segment | Operating Segments
Segment Reporting Information [Line Items]
Net sales	94,314,000	77,973,000
Operating income (loss)	9,841,000	7,058,000
Net income (loss)	9,867,000	6,971,000
Provision for (benefit from) income taxes	13,000	12,000
Interest (income) and other expense	(47,000)	53,000
Write-off of deferred financing costs		0
Interest expense	8,000	22,000
Amortization of stock-based compensation	0	0
Amortization of intangibles	4,362,000	3,445,000
Depreciation	2,196,000	2,228,000
Estimated contract settlement costs	230,000
Facility exit costs		0
Adjusted EBITDA	16,629,000	12,731,000
Purchases of property, plant and equipment	1,000,000	892,000
Total assets	675,344,000	602,567,000
Acquisition plan expenses	0	0
Commercial Solutions Segment | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales	1,899,000	8,540,000
Government Solutions Segment
Segment Reporting Information [Line Items]
Net sales	75,953,000	82,871,000
Government Solutions Segment | Operating Segments
Segment Reporting Information [Line Items]
Net sales	75,953,000	82,871,000
Operating income (loss)	7,083,000	6,644,000
Net income (loss)	7,095,000	6,609,000
Provision for (benefit from) income taxes	0	0
Interest (income) and other expense	(13,000)	32,000
Write-off of deferred financing costs		0
Interest expense	1,000	3,000
Amortization of stock-based compensation	0	0
Amortization of intangibles	844,000	844,000
Depreciation	313,000	379,000
Estimated contract settlement costs	0
Facility exit costs		1,373,000
Adjusted EBITDA	8,240,000	9,240,000
Purchases of property, plant and equipment	224,000	629,000
Total assets	211,125,000	222,587,000
Acquisition plan expenses	$ 0	0
June Two Thousand Seventeen Amendment To Credit Facility [Member]
Segment Reporting Information [Line Items]
Write-off of deferred financing costs		$ 3,217,000