Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
REVENUES:
Revenues	$ 48,260	$ 50,619
COSTS AND EXPENSES:
Marketing and advertising	3,799	4,276
Employee benefits	1,973	1,972
Depreciation and amortization	1,760	1,985
General, administrative and other	6,553	5,213
Total costs and expenses	46,137	47,119
OPERATING INCOME	2,123	3,500
OTHER INCOME (EXPENSE):
Interest expense	(331)	(403)
Other income (expense), net	4	(16)
Gain on sale and disposal of assets		1
Total other income (expense)	(327)	(418)
INCOME BEFORE INCOME TAXES	1,796	3,082
PROVISION (BENEFIT) FOR INCOME TAXES
Provision (benefit) for income taxes	(192)	589
Deferred income tax	732	179
NET INCOME	1,256	2,314
Net income attributable to noncontrolling interest in BHCMC, LLC	(915)	(780)
NET INCOME ATTRIBUTABLE TO BUTLER NATIONAL CORPORATION	$ 341	$ 1,534
BASIC EARNINGS PER COMMON SHARE ATTRIBUTABLE TO BUTLER NATIONAL CORPORATION (in dollars per share)	$ 0.01	$ 0.02
WEIGHTED AVERAGE SHARES USED IN PER SHARE CALCULATION (in shares)	64,387,694	63,455,883
DILUTED EARNINGS PER COMMON SHARE ATTRIBUTABLE TO BUTLER NATIONAL CORPORATION (in dollars per share)	$ 0.01	$ 0.02
WEIGHTED AVERAGE SHARES USED IN PER SHARE CALCULATION (in shares)	64,387,694	63,455,883
Professional Services [Member]
REVENUES:
Revenues	$ 31,283	$ 30,849
COSTS AND EXPENSES:
Cost of services and products	19,574	19,126
Aerospace Products [Member]
REVENUES:
Revenues	16,977	19,770
COSTS AND EXPENSES:
Cost of services and products	$ 12,478	$ 14,547