Business Segments and Major Customer Information - Segment Reporting Information (Details) - USD ($)	3 Months Ended								7 Months Ended		12 Months Ended
	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Aug. 31, 2018	Aug. 31, 2017	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 85,761,000	$ 100,533,000	$ 98,058,000	$ 98,178,000	$ 88,022,000	$ 104,833,000	$ 102,684,000	$ 111,129,000			$ 382,530,000	$ 406,668,000	$ 377,317,000
Operating income(a)	2,916,000	11,332,000	10,570,000	15,121,000	3,361,000	13,612,000	16,629,000	21,531,000			39,939,000	55,133,000	59,170,000
Assets(b)	403,257,000				360,245,000						403,257,000	360,245,000	326,803,000
Capital expenditures											8,560,000	14,127,000	12,011,000
Depreciation and amortization											16,241,000	15,123,000	14,802,000
Applied Technology
Segment Reporting Information [Line Items]
Net sales											130,460,000	129,749,000	124,688,000
Operating Expenses	3,152,000
Engineered Films
Segment Reporting Information [Line Items]
Net sales											197,719,000	226,574,000	213,298,000
Engineered Films | Hurricane Recovery Film
Segment Reporting Information [Line Items]
Net sales	27,000	$ 1,010,000	$ 806,000	$ 17,000	4,065,000	$ 1,510,000	$ 0	8,919,000			1,860,000	14,494,000	24,225,000
Engineered Films | CLI
Segment Reporting Information [Line Items]
Net sales									$ 21,568,000	$ 4,109,000
Aerostar
Segment Reporting Information [Line Items]
Net sales											54,443,000	50,867,000	39,915,000
Corporate & Other
Segment Reporting Information [Line Items]
Operating income(a)											(28,025,000)	(31,769,000)	(23,553,000)
Assets(b)	46,257,000				99,500,000						46,257,000	99,500,000	72,704,000
Capital expenditures											1,127,000	2,365,000	2,051,000
Depreciation and amortization											1,795,000	1,650,000	1,290,000
Operating Segments
Segment Reporting Information [Line Items]
Net sales											382,530,000	406,668,000	377,317,000
Operating income(a)											67,964,000	86,902,000	82,723,000
Assets(b)	357,000,000				260,745,000						357,000,000	260,745,000	254,099,000
Capital expenditures											7,433,000	11,762,000	9,960,000
Depreciation and amortization											14,446,000	13,473,000	13,512,000
Operating Segments | Applied Technology
Segment Reporting Information [Line Items]
Net sales											130,460,000	129,749,000	124,688,000
Operating income(a)											30,672,000	39,044,000	31,257,000
Assets(b)	172,320,000				79,742,000						172,320,000	79,742,000	66,555,000
Capital expenditures											1,464,000	2,050,000	1,489,000
Depreciation and amortization											3,995,000	3,433,000	3,365,000
Operating Segments | Engineered Films
Segment Reporting Information [Line Items]
Net sales											197,719,000	226,574,000	213,298,000
Operating income(a)											28,695,000	39,714,000	47,324,000
Assets(b)	158,440,000				159,592,000						158,440,000	159,592,000	168,797,000
Capital expenditures											5,317,000	9,544,000	8,128,000
Depreciation and amortization											9,518,000	9,149,000	8,761,000
Operating Segments | Aerostar
Segment Reporting Information [Line Items]
Net sales											54,443,000	50,867,000	39,915,000
Operating income(a)											8,597,000	8,179,000	4,122,000
Assets(b)	26,344,000				21,515,000						26,344,000	21,515,000	22,127,000
Capital expenditures											652,000	168,000	343,000
Depreciation and amortization											933,000	891,000	1,386,000
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating income(a)											0	(35,000)	20,000
Assets(b)	(104,000)				$ (104,000)						(104,000)	(104,000)	(3,380,000)
Intersegment Eliminations | Applied Technology
Segment Reporting Information [Line Items]
Net sales											(2,000)	(10,000)	0
Intersegment Eliminations | Engineered Films
Segment Reporting Information [Line Items]
Net sales											(90,000)	(512,000)	(584,000)
Charitable Gift
Segment Reporting Information [Line Items]
Loss Contingency, Loss in Period								$ 4,503,000				4,503,000
Project Atlas
Segment Reporting Information [Line Items]
Other General and Administrative Expense											$ 2,700,000	$ 4,000,000	$ 900,000
Autonomy | Applied Technology
Segment Reporting Information [Line Items]
Operating Expenses	$ 2,834,000