CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Capital Contributed in Excess of Par [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Total Stockholders' Equity Butler National Corporation [Member]	Noncontrolling Interest in BHCMC, LLC [Member]	Total
BALANCE at Apr. 30, 2014	$ 614	$ 13,282	$ (732)	$ 8,134	$ 21,298	$ 3,056	$ 24,354
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock for services and other							0
Issuance of stock benefit plan	14	205	0	0	219	0	219
Net income	0	0	0	27	27	802	829
BALANCE at Apr. 30, 2015	628	13,487	(732)	8,161	21,544	3,858	25,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock for services and other							0
BHCMC distribution noncontrolling member	0	0	0	0	0	(360)	(360)
Issuance of stock benefit plan	12	229	0	0	241	0	241
Net income	0	0	0	24	24	791	815
BALANCE at Apr. 30, 2016	$ 640	$ 13,716	$ (732)	$ 8,185	$ 21,809	$ 4,289	$ 26,098