INDUSTRY SEGMENTATION AND SALES BY MAJOR CUSTOMER (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Jan. 31, 2014	Apr. 30, 2013 Customer	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2013 Segment Customer		Apr. 30, 2012		Apr. 30, 2011
INDUSTRY SEGMENTATION AND SALES BY MAJOR CUSTOMER [Abstract]
Number of primary activities													2
Segment Reporting Information [Line Items]
Total revenues	$ 11,000	$ 12,824	$ 13,537	$ 13,468	$ 14,393	$ 13,734	$ 14,141	$ 12,146	$ 12,913	$ 12,860	$ 11,016	$ 9,546	$ 50,829		$ 54,414		$ 46,335
Depreciation/Amortization													3,276		2,199		1,411
Operating income (loss)	(520)	38	700	1,285	1,864	1,568	1,380	674	598	1,514	780	(64)	1,503		5,486		2,828
Capital Expenditures, net													8,159		3,534		3,753
Interest Expense													(1,521)		(736)		(364)
Other income (expense)													11		(11)		(35)
Income (loss) before taxes													(7)		4,739		2,429
Income tax expense (benefit)													(816)		823		1,171
Net income (loss) attributable to Butler National Corporation	(755)	225	114	268	765	568	459	108	31	867	473	(112)	(148)		1,900		1,259
Identifiable assets net		43,860			40,562				32,158				43,860		40,562		32,158
Revenue, Major Customer [Line Items]
Revenue from major customers (in hundredths)													14.80%
Number of major customers		5											5
Next Top Four Customers [Member] | Minimum [Member]
Revenue, Major Customer [Line Items]
Revenue from major customers (in hundredths)													1.30%
Next Top Four Customers [Member] | Maximum [Member]
Revenue, Major Customer [Line Items]
Revenue from major customers (in hundredths)													3.90%
Modifications [Member]
Revenue, Major Customer [Line Items]
Revenue from major customers (in hundredths)														[1]		[1]	11.20%
Avionics [Member]
Revenue, Major Customer [Line Items]
Revenue from major customers (in hundredths)														[1]		[1]		[1]
Management Services [Member]
Revenue, Major Customer [Line Items]
Revenue from major customers (in hundredths)														[1]		[1]		[1]
Environmental Services [Member]
Revenue, Major Customer [Line Items]
Revenue from major customers (in hundredths)														[1]		[1]		[1]
Professional Services [Member]
Segment Reporting Information [Line Items]
Total revenues													37,202		37,226		27,390
Depreciation/Amortization													1,285		364		66
Operating income (loss)													2,987		2,928		(728)
Capital Expenditures, net													7,180		2,211		242
Interest Expense													0		0		0
Other income (expense)													0		0		0
Income (loss) before taxes													0		0		0
Income tax expense (benefit)													0		0		0
Net income (loss) attributable to Butler National Corporation													0		0		0
Identifiable assets net		23,880			19,535				10,016				23,880		19,535		10,016
Aerospace Products [Member]
Segment Reporting Information [Line Items]
Total revenues													13,627		17,188		18,945
Depreciation/Amortization													1,991		1,835		1,345
Operating income (loss)													(1,484)		2,558		3,556
Capital Expenditures, net													979		1,323		3,511
Interest Expense													0		0		0
Other income (expense)													0		0		0
Income (loss) before taxes													0		0		0
Income tax expense (benefit)													0		0		0
Net income (loss) attributable to Butler National Corporation													0		0		0
Identifiable assets net		$ 19,980			$ 21,027				$ 22,142				$ 19,980		$ 21,027		$ 22,142

[1] Revenue represented less than 10% of consolidated revenue.