Segment Reporting Business segment net sales and operating income results (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011	Jan. 31, 2011	Jan. 31, 2012	Oct. 31, 2012 Applied Technology [Member]	Oct. 31, 2011 Applied Technology [Member]	Oct. 31, 2012 Applied Technology [Member]	Oct. 31, 2011 Applied Technology [Member]	Oct. 31, 2012 Engineered Films [Member]	Oct. 31, 2011 Engineered Films [Member]	Oct. 31, 2012 Engineered Films [Member]	Oct. 31, 2011 Engineered Films [Member]	Oct. 31, 2012 Aerostar [Member]	Oct. 31, 2011 Aerostar [Member]	Oct. 31, 2012 Aerostar [Member]	Oct. 31, 2011 Aerostar [Member]	Oct. 31, 2012 Intersegment Eliminations [Member]		Oct. 31, 2011 Intersegment Eliminations [Member]		Oct. 31, 2012 Intersegment Eliminations [Member]		Oct. 31, 2011 Intersegment Eliminations [Member]		Oct. 31, 2012 Reportable Segment [Member]	Oct. 31, 2011 Reportable Segment [Member]	Oct. 31, 2012 Reportable Segment [Member]	Oct. 31, 2011 Reportable Segment [Member]	Jan. 31, 2012 Previously Reported [Member]	Jan. 31, 2011 Previously Reported [Member]		Jan. 31, 2010 Previously Reported [Member]	Jan. 31, 2012 Previously Reported [Member] Applied Technology [Member]	Jan. 31, 2011 Previously Reported [Member] Applied Technology [Member]	Jan. 31, 2010 Previously Reported [Member] Applied Technology [Member]	Jan. 31, 2012 Previously Reported [Member] Engineered Films [Member]	Jan. 31, 2011 Previously Reported [Member] Engineered Films [Member]		Jan. 31, 2010 Previously Reported [Member] Engineered Films [Member]	Jan. 31, 2012 Previously Reported [Member] Aerostar [Member]	Jan. 31, 2011 Previously Reported [Member] Aerostar [Member]	Jan. 31, 2010 Previously Reported [Member] Aerostar [Member]	Jan. 31, 2012 Previously Reported [Member] Electronic Systems [Member]	Jan. 31, 2011 Previously Reported [Member] Electronic Systems [Member]	Jan. 31, 2010 Previously Reported [Member] Electronic Systems [Member]	Jan. 31, 2012 Previously Reported [Member] Intersegment Eliminations [Member]	Jan. 31, 2011 Previously Reported [Member] Intersegment Eliminations [Member]	Jan. 31, 2010 Previously Reported [Member] Intersegment Eliminations [Member]	Jan. 31, 2012 Previously Reported [Member] Reportable Segment [Member]	Jan. 31, 2011 Previously Reported [Member] Reportable Segment [Member]		Jan. 31, 2010 Previously Reported [Member] Reportable Segment [Member]	Jan. 31, 2012 Previously Reported [Member] Corporate & Other [Member]		Jan. 31, 2011 Previously Reported [Member] Corporate & Other [Member]		Jan. 31, 2010 Previously Reported [Member] Corporate & Other [Member]		Jan. 31, 2012 Revised [Member]	Jan. 31, 2011 Revised [Member]		Jan. 31, 2010 Revised [Member]	Jan. 31, 2012 Revised [Member] Applied Technology [Member]	Jan. 31, 2011 Revised [Member] Applied Technology [Member]	Jan. 31, 2010 Revised [Member] Applied Technology [Member]	Jan. 31, 2012 Revised [Member] Engineered Films [Member]	Jan. 31, 2011 Revised [Member] Engineered Films [Member]		Jan. 31, 2010 Revised [Member] Engineered Films [Member]	Jan. 31, 2012 Revised [Member] Aerostar [Member]	Jan. 31, 2011 Revised [Member] Aerostar [Member]	Jan. 31, 2010 Revised [Member] Aerostar [Member]	Jan. 31, 2012 Revised [Member] Electronic Systems [Member]	Jan. 31, 2011 Revised [Member] Electronic Systems [Member]	Jan. 31, 2010 Revised [Member] Electronic Systems [Member]	Jan. 31, 2012 Revised [Member] Intersegment Eliminations [Member]	Jan. 31, 2011 Revised [Member] Intersegment Eliminations [Member]	Jan. 31, 2010 Revised [Member] Intersegment Eliminations [Member]	Jan. 31, 2012 Revised [Member] Reportable Segment [Member]	Jan. 31, 2011 Revised [Member] Reportable Segment [Member]		Jan. 31, 2010 Revised [Member] Reportable Segment [Member]	Jan. 31, 2012 Revised [Member] Corporate & Other [Member]		Jan. 31, 2011 Revised [Member] Corporate & Other [Member]		Jan. 31, 2010 Revised [Member] Corporate & Other [Member]
Segment Reporting Information [Line Items]
Sales	$ 97,011	$ 93,300	$ 316,600	$ 285,185			$ 39,534	$ 35,263	$ 133,346	$ 112,716	$ 33,316	$ 34,947	$ 111,195	$ 97,497	$ 26,385	$ 24,173	$ 78,865	$ 78,126	$ (2,224)	[1]	$ (1,083)	[1]	$ (6,806)	[1]	$ (3,154)	[1]					$ 381,511	$ 314,708		$ 237,782	$ 132,632	$ 100,090	$ 86,217	$ 133,481	$ 105,838		$ 63,783	$ 52,351	$ 48,787	$ 27,244	$ 71,744	$ 65,852	$ 63,525				$ 381,511	$ 314,708		$ 237,782							$ 381,511	$ 314,708		$ 237,782	$ 145,261	$ 107,910	$ 94,005	$ 133,481	$ 105,838		$ 63,783	$ 107,811	$ 104,384	$ 81,617	$ 0	$ 0	$ 0				$ 381,511	$ 314,708		$ 237,782
Operating income	(16,372)	(16,875)	(62,211)	(59,082)			12,289	11,547	(47,248)	(40,950)	4,729	5,574	(20,727)	(14,987)	3,830	3,198	(7,581)	(12,972)	(25)	[1]	6	[1]	87	[1]	(6)	[1]	20,823	20,325	75,469	68,915	(75,641)	(60,203)	[2]	(43,220)	(45,358)	(31,135)	(25,722)	(21,501)	(19,622)	[2]	(10,232)	(11,468)	(9,407)	(5,634)	(11,264)	(9,917)	(8,979)	(220)	(94)	60	(89,371)	(69,987)	[2]	(50,627)	13,730		9,784		7,407		(75,641)	(60,203)	[2]	(43,220)	(49,750)	(33,197)	(27,538)	(21,501)	(19,622)	[2]	(10,232)	(18,308)	(17,209)	(12,849)	0	0	0	(188)	(41)	8	(89,371)	(69,987)	[2]	(50,627)	13,730		9,784		7,407
General and Administrative Expense	4,451	3,450	(13,258)	(9,833)
Assets	272,175	223,137	272,175	223,137		245,703																									245,703	187,760		170,309	69,977	52,669	51,029	65,100	46,519		35,999	51,822	18,140	10,462	24,281	23,385	21,216	(405)	(186)	(92)	210,775	140,527		118,614	34,928	[3]	47,233	[3]	51,695	[3]	245,703	187,760		170,309	73,872	55,740	54,007	65,100	46,519		35,999	72,089	38,366	28,665	0	0	0	(286)	(98)	(57)	210,775	140,527		118,614	34,928	[3]	47,233	[3]	51,695	[3]
Payments to Acquire Property, Plant, and Equipment			22,840	22,070																											29,015	13,972		3,302	11,408	1,769	941	10,937	8,450		1,460	3,875	2,190	332	793	609	290				27,013	13,018		3,023	2,002		954		279		29,015	13,972		3,302	11,971	1,947	1,092	10,937	8,450		1,460	4,105	2,621	471	0	0	0				27,013	13,018		3,023	2,002		954		279
Depreciation, Depletion and Amortization																															9,268	7,631		7,108	2,351	2,238	1,677	4,313	3,452		3,707	1,079	757	398	825	823	939				8,568	7,270		6,721	700		361		387		9,268	7,631		7,108	2,571	2,483	1,863	4,313	3,452		3,707	1,684	1,335	1,151	0	0	0				8,568	7,270		6,721	700		361		387
Segment Reporting Information, Intersegment Revenue																																			0	0	0	(193)	(307)		(210)	(1)	(32)	(1)	(8,503)	(5,520)	(2,776)																		(460)	(226)	(31)	(193)	(307)		(210)	(4,389)	(2,891)	(1,382)	0	0	0
Pre-tax gain on disposition of assets					$ 451

[1] Intersegment sales were primarily from Aerostar to Applied Technology.

[2] The year ended January 31, 2011 includes a $451 pre-tax gain on disposition of assets.

[3] Assets are principally cash, investments, deferred taxes, and other receivables.