Note 12 - Segment Information (Details) - Segment Reporting Information (USD $)	3 Months Ended		9 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2013	Aug. 31, 2012	Nov. 30, 2012
Segment Reporting Information [Line Items]
Revenue from external customers	$ 9,350,391	$ 11,533,882	$ 27,015,804	$ 29,531,268
Income (loss) from operations	54,119	1,606,523	1,565,832	3,462,544
Income (loss) before tax	49,000	1,495,000	2,020,000	3,189,000
Total Assets	30,384,258	32,894,000	30,384,258	32,894,000	31,228,676
Capital expenditures	563,000	294,000	773,000	1,961,000
Depreciation & Amortization	188,000	218,000	558,000	634,000
Agricultural Products [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	8,005,000	8,176,000	22,727,000	20,170,000
Income (loss) from operations	145,000	1,027,000	1,274,000	2,202,000
Income (loss) before tax	108,000	988,000	1,800,000	2,149,000
Total Assets	24,563,000	24,082,000	24,563,000	24,082,000
Capital expenditures	540,000	289,000	737,000	1,929,000
Depreciation & Amortization	113,000	137,000	329,000	390,000
Pressurized Vessels [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	635,000	566,000	1,671,000	1,512,000
Income (loss) from operations	22,000	10,000	(114,000)	(108,000)
Income (loss) before tax	14,000	(47,000)	(200,000)	(278,000)
Total Assets	2,815,000	2,722,000	2,815,000	2,722,000
Capital expenditures	10,000	0	18,000	5,000
Depreciation & Amortization	26,000	29,000	79,000	86,000
Modular Buildings [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	710,000	2,792,000	2,618,000	7,849,000
Income (loss) from operations	(113,000)	570,000	406,000	1,369,000
Income (loss) before tax	(73,000)	554,000	420,000	1,318,000
Total Assets	3,006,000	6,090,000	3,006,000	6,090,000
Capital expenditures	13,000	5,000	18,000	27,000
Depreciation & Amortization	$ 49,000	$ 52,000	$ 150,000	$ 158,000