CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Common Stock owed but Not issued [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, 2012	$ 579	$ 3	$ 12,567	$ (732)	$ 8,170	$ 20,587	$ 2,017	$ 22,604
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock for services and other	2	(3)	91	0	0	90	0	90
Stock options issued to employees and directors	0	0	110	0	0	110	0	110
BHCMC distribution noncontrolling member	0	0	0	0	0	0	(320)	(320)
Issuance of stock benefit plan	15	0	266	0	0	281	0	281
Net income	0	0	0	0	(148)	(148)	957	809
BALANCE at Apr. 30, 2013	596	0	13,034	(732)	8,022	20,920	2,654	23,574
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options issued to employees and directors	0	0	22	0	0	22	0	22
Issuance of stock benefit plan	18	0	226	0	0	244	0	244
Net income	0	0	0	0	112	112	402	514
BALANCE at Apr. 30, 2014	614	0	13,282	(732)	8,134	21,298	3,056	24,354
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock benefit plan	14	0	205	0	0	219	0	219
Net income	0	0	0	0	27	27	802	829
BALANCE at Apr. 30, 2015	$ 628	$ 0	$ 13,487	$ (732)	$ 8,161	$ 21,544	$ 3,858	$ 25,402