Note 12 - Segment Information (Details) - Segment Reporting Information (USD $)	3 Months Ended		9 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2014	Aug. 31, 2013	Nov. 30, 2013
Segment Reporting Information [Line Items]
Revenue from external customers	$ 11,584,707	$ 9,350,391	$ 27,291,037	$ 27,015,804
Income (loss) from operations	907,772	54,119	1,056,728	1,565,832
Income (loss) before tax	844,525	49,187	835,425	2,020,397
Total Assets	35,091,487		35,091,487		32,767,621
Capital expenditures			651,251	684,809
Depreciation & Amortization			633,123	558,292
Agricultural Products [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	9,362,000	8,005,000	21,366,000	22,727,000
Income (loss) from operations	1,034,000	145,000	1,430,000	1,274,000
Income (loss) before tax	991,000	108,000	1,294,000	1,800,000
Total Assets	26,426,000	24,563,000	26,426,000	24,563,000
Capital expenditures	39,000	540,000	629,000	737,000
Depreciation & Amortization	147,000	113,000	356,000	329,000
Pressurized Vessels [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	606,000	635,000	1,504,000	1,671,000
Income (loss) from operations	(59,000)	22,000	(168,000)	(114,000)
Income (loss) before tax	(64,000)	14,000	(190,000)	(200,000)
Total Assets	2,489,000	2,815,000	2,489,000	2,815,000
Capital expenditures	0	10,000	11,000	18,000
Depreciation & Amortization	27,000	26,000	81,000	79,000
Modular Buildings [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	820,000	710,000	1,818,000	2,618,000
Income (loss) from operations	7,000	(113,000)	(233,000)	406,000
Income (loss) before tax	0	(73,000)	(249,000)	420,000
Total Assets	2,842,000	3,006,000	2,842,000	3,006,000
Capital expenditures	0	13,000	0	18,000
Depreciation & Amortization	36,000	49,000	110,000	150,000
Tools [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	797,000	0	2,603,000	0
Income (loss) from operations	(74,000)	0	28,000	0
Income (loss) before tax	(82,000)	0	(18,000)	0
Total Assets	3,334,000	0	3,334,000	0
Capital expenditures	1,000	0	11,000	0
Depreciation & Amortization	29,000	0	86,000	0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	11,585,000	9,350,000	27,291,000	27,016,000
Income (loss) from operations	908,000	54,000	1,057,000	1,566,000
Income (loss) before tax	845,000	49,000	835,000	2,020,000
Total Assets	35,091,000	30,384,000	35,091,000	30,384,000
Capital expenditures	40,000	563,000	651,000	773,000
Depreciation & Amortization	$ 239,000	$ 188,000	$ 633,000	$ 558,000