Consolidated Balance Sheets - USD ($) $ in Thousands	Apr. 30, 2017	Apr. 30, 2016
CURRENT ASSETS:
Cash	$ 6,389	$ 7,381
Accounts receivable, net of allowance for doubtful accounts	4,095	1,574
Inventories
Parts and raw materials	5,644	6,339
Work in process	1,174	1,349
Finished goods	39	275
Total inventory, net of allowance	6,857	7,963
Prepaid expenses and other current assets	994	873
Total current assets	18,335	17,791
PROPERTY, PLANT AND EQUIPMENT:
Land and building	5,132	4,081
Aircraft	5,888	5,712
Machinery and equipment	3,639	3,630
Office furniture and fixtures	6,497	5,637
Leasehold improvements	4,032	4,032
	25,188	23,092
Accumulated depreciation	(14,506)	(13,218)
Total property, plant and equipment	10,682	9,874
SUPPLEMENTAL TYPE CERTIFICATES (net of accumulated amortization of $4,345 at April 30, 2017 and $3,549 at April 30, 2016)	6,354	6,481
OTHER ASSETS:
Deferred tax asset	925	1,104
Other assets (net of accumulated amortization of $6,904 at April 30, 2017 and $5,579 at April 30, 2016)	6,482	7,447
Total other assets	7,407	8,551
Total assets	42,778	42,697
CURRENT LIABILITIES:
Promissory notes	2,604	3,988
Current maturities of long-term debt	2,297	2,464
Accounts payable	1,919	2,018
Customer deposits	892	258
Gaming facility mandated payment	1,227	1,206
Compensation and compensated absences	1,478	1,322
Income tax payable	589
Other current liabilities	129	125
Total current liabilities	11,135	11,381
LONG-TERM DEBT, NET OF CURRENT MATURITIES:	3,347	5,218
Total liabilities	14,482	16,599
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Common stock, par value $.01: authorized 100,000,000 shares issued 65,273,896 shares, and outstanding 64,543,550 shares at April 30, 2017 and issued 64,066,873 shares, and outstanding 63,466,873 shares at April 30, 2016	652	640
Capital contributed in excess of par	13,980	13,716
Treasury stock at cost, 730,346 shares at April 30, 2017 and 600,000 shares at April 30, 2016	(764)	(732)
Retained earnings	9,719	8,185
Total Butler National Corporation's stockholders' equity	23,587	21,809
Noncontrolling interest in BHCMC, LLC	4,709	4,289
Total stockholders' equity	28,296	26,098
Total liabilities and stockholders' equity	42,778	42,697
Preferred Class A [Member]
STOCKHOLDERS' EQUITY:
Preferred stock
Preferred Class B [Member]
STOCKHOLDERS' EQUITY:
Preferred stock