Segment Information (Details) - USD ($)	3 Months Ended												12 Months Ended
	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Segment Reporting Information, Profit (Loss)
Net Sales	$ 167,435,000	$ 147,854,000	$ 133,731,000	$ 121,569,000	$ 147,762,000	$ 127,792,000	$ 139,028,000	$ 135,786,000	$ 152,377,000	$ 124,187,000	$ 70,323,000	$ 64,117,000	$ 570,589,000	$ 550,368,000	$ 411,004,000
Operating income (loss)													35,075,000	37,042,000	(576,000)
Net income (loss)	7,458,000	$ 8,210,000	$ 15,761,000	$ (1,660,000)	7,314,000	$ 4,417,000	$ 6,585,000	$ (2,489,000)	2,702,000	$ (14,355,000)	$ 2,476,000	$ 1,439,000	29,769,000	15,827,000	(7,738,000)
Provision for (benefit from) income taxes													(5,143,000)	9,654,000	(454,000)
Interest (income) and other													254,000	(68,000)	(134,000)
Interest expense													10,195,000	11,629,000	7,750,000
Amortization of stock-based compensation													8,569,000	8,506,000	4,117,000
Amortization of intangibles													21,075,000	22,823,000	13,415,000
Depreciation and amortization of property, plant and equipment													13,655,000	14,354,000	9,830,000
Acquisition plan expenses															21,276,000
Settlement Of Intellectual Property Litigation													0	(12,020,000)	0
Adjusted EBITDA													78,374,000	70,705,000	48,062,000
Purchases of property, plant and equipment													8,642,000	8,150,000	5,667,000
Long-lived assets acquired in connection with the TCS acquisition															455,084,000
Total assets	845,157,000				832,063,000				921,196,000				845,157,000	832,063,000	921,196,000
Secured Credit Facility
Segment Reporting Information, Profit (Loss)
Interest expense related to credit facility													9,614,000	11,106,000	6,933,000
Unallocated
Segment Reporting Information, Profit (Loss)
Net Sales													0	0	0
Operating income (loss)													(16,712,000)	(5,585,000)	(46,837,000)
Net income (loss)													(21,363,000)	(26,465,000)	(53,541,000)
Provision for (benefit from) income taxes													(5,413,000)	9,396,000	(526,000)
Interest (income) and other													(9,000)	74,000	(232,000)
Interest expense													10,073,000	11,410,000	7,462,000
Amortization of stock-based compensation													8,569,000	8,506,000	4,117,000
Amortization of intangibles													0	0	0
Depreciation and amortization of property, plant and equipment													1,088,000	1,478,000	751,000
Acquisition plan expenses															21,276,000
Settlement Of Intellectual Property Litigation														(12,020,000)
Adjusted EBITDA													(7,055,000)	(7,621,000)	(20,693,000)
Purchases of property, plant and equipment													590,000	97,000	75,000
Long-lived assets acquired in connection with the TCS acquisition															4,359,000
Total assets	39,067,000				40,393,000				62,395,000				39,067,000	40,393,000	62,395,000
Commercial Solutions | Operating Segments
Segment Reporting Information, Profit (Loss)
Net Sales													345,076,000	330,867,000	248,955,000
Operating income (loss)													40,837,000	33,234,000	23,255,000
Net income (loss)													40,297,000	32,871,000	22,785,000
Provision for (benefit from) income taxes													270,000	258,000	72,000
Interest (income) and other													151,000	(108,000)	109,000
Interest expense													119,000	213,000	289,000
Amortization of stock-based compensation													0	0	0
Amortization of intangibles													17,699,000	17,698,000	10,592,000
Depreciation and amortization of property, plant and equipment													9,479,000	9,938,000	7,073,000
Acquisition plan expenses															0
Settlement Of Intellectual Property Litigation														0
Adjusted EBITDA													68,015,000	60,870,000	40,920,000
Purchases of property, plant and equipment													7,151,000	7,007,000	4,614,000
Long-lived assets acquired in connection with the TCS acquisition															367,865,000
Total assets	610,166,000				606,436,000				631,936,000				610,166,000	606,436,000	631,936,000
Commercial Solutions | Intersegment Eliminations
Segment Reporting Information, Profit (Loss)
Net Sales													9,630,000	12,492,000	6,266,000
Government Solutions | Operating Segments
Segment Reporting Information, Profit (Loss)
Net Sales													225,513,000	219,501,000	162,049,000
Operating income (loss)													10,950,000	9,393,000	23,006,000
Net income (loss)													10,835,000	9,421,000	23,018,000
Provision for (benefit from) income taxes													0	0	0
Interest (income) and other													112,000	(34,000)	(11,000)
Interest expense													3,000	6,000	(1,000)
Amortization of stock-based compensation													0	0	0
Amortization of intangibles													3,376,000	5,125,000	2,823,000
Depreciation and amortization of property, plant and equipment													3,088,000	2,938,000	2,006,000
Acquisition plan expenses															0
Settlement Of Intellectual Property Litigation														0
Adjusted EBITDA													17,414,000	17,456,000	27,835,000
Purchases of property, plant and equipment													901,000	1,046,000	978,000
Long-lived assets acquired in connection with the TCS acquisition															82,860,000
Total assets	$ 195,924,000				$ 185,234,000				$ 226,865,000				$ 195,924,000	$ 185,234,000	$ 226,865,000