Statements of Shareholders' Equity (Unaudited) - USD ($)
Cumulative Effect, Period of Adoption, Adjustment [Member]
Common Stock [Member]
Common Stock [Member]
Additional Paid-in Capital [Member]
AOCI Attributable to Parent [Member]
Retained Earnings [Member]
Total
Balance (in shares) at Mar. 31, 2019   4,846,010        
Balance at Mar. 31, 2019   $ 48,460 $ 19,910,558 $ (82,725) $ 62,903,918 $ 82,780,211
Unrealized gain on marketable securities, net of tax   570,063 570,063
Net income         3,607,419 3,607,419
Total comprehensive income           4,177,482
Cash dividends declared         (4,846,010) (4,846,010)
Balance (in shares) at Jun. 30, 2019 4,846,010          
Balance at Jun. 30, 2019   $ 48,460 19,910,558 487,338 61,665,327 82,111,683
Balance (in shares) at Mar. 31, 2019   4,846,010        
Balance at Mar. 31, 2019   $ 48,460 19,910,558 (82,725) 62,903,918 82,780,211
Unrealized gain on marketable securities, net of tax           1,242,662
Net income           2,411,865
Total comprehensive income           3,654,527
Balance (in shares) at Mar. 31, 2020   4,835,038        
Balance at Mar. 31, 2020   $ 48,350 19,383,956 516,523 58,046,520 77,995,349 [1]
Unrealized gain on marketable securities, net of tax   1,242,662 1,242,662
Net income         2,411,865 2,411,865
Total comprehensive income           3,654,527
Stock-based compensation   2,707 2,707
Cash dividends declared         (4,835,038) (4,835,038)
Balance (in shares) at Jun. 30, 2020 4,835,038          
Balance at Jun. 30, 2020   $ 48,350 $ 19,386,663 $ 1,759,185 $ 55,623,347 $ 76,817,545
[1] The March 31, 2020 Balance Sheet is derived from the audited financial statements contained in our Annual Report on Form 10-K for the fiscal year ended March 31, 2020.