Consolidated Statements of Equity - USD ($)		Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Mar. 31, 2017		2,042,789
Balance at Mar. 31, 2017		$ 510,696	$ 4,205,536	$ 18,461,347	$ (212,047)	$ (803,138)	$ 22,162,394
Net income*	[1]			2,277,109		(75,440)	2,201,669
Loss on marketable securities, net of tax					(317,132)		(317,132)
Foreign currency translation gain					225,804	3,811	229,615
Redeemable non-controlling interest			(42,100)				(42,100)
Reclassification due to the Tax Cuts and Jobs Act				(42,475)	42,475
Exercise of stock options (in shares)		818					818
Exercise of stock options		$ 205	8,433				$ 8,638
Unrealized gain (loss) on interest rate swaps, net of tax
Balance (in shares) at Mar. 31, 2018		2,043,607
Balance at Mar. 31, 2018		$ 510,901	4,171,869	20,695,981	(260,900)	(874,767)	24,243,084
Net income*	[1]			1,339,995		(166,116)	1,173,879
Foreign currency translation gain					185,159	40,255	225,414
Redeemable non-controlling interest			(1,322,516)				$ (1,322,516)
Exercise of stock options (in shares)		1,682					1,682
Exercise of stock options		$ 421	17,342				$ 17,763
Adoption of ASU 2016-01				(106,341)	106,341
Repurchase of common stock (in shares)		(22,652)
Repurchase of common stock		$ (5,665)		(738,509)			(744,174)
Unrealized gain (loss) on interest rate swaps, net of tax					(235,686)		(235,686)
Balance (in shares) at Mar. 31, 2019		2,022,637
Balance at Mar. 31, 2019		$ 505,657	$ 2,866,695	$ 21,191,126	$ (205,086)	$ (1,000,628)	$ 23,357,764

[1] Excludes amount attributable to redeemable non-controlling interest in Contrail Aviation.