Statements of Shareholders' Equity - USD ($)
|
Common Stock [Member] |
Additional Paid-in Capital [Member] |
AOCI Attributable to Parent [Member] |
Retained Earnings [Member] |
Total |
| Balance (in shares) at Mar. 31, 2015 |
4,857,953
|
|
|
|
|
| Balance at Mar. 31, 2015 |
$ 48,580
|
$ 20,850,762
|
$ 746,447
|
$ 86,681,745
|
$ 108,327,534
|
| Exercise of stock options (in shares) |
18,090
|
|
|
|
|
| Exercise of stock options |
$ 181
|
292,728
|
|
|
292,909
|
| Repurchase of common stock (in shares) |
(41,033)
|
|
|
|
|
| Repurchase of common stock |
$ (411)
|
(2,311,262)
|
|
|
(2,311,673)
|
| Comprehensive income: |
|
|
|
|
|
| Unrealized loss from marketable securities, net of tax |
|
|
(295,088)
|
|
(295,088)
|
| Net income |
|
|
|
12,292,315
|
12,292,315
|
| Total comprehensive income |
|
|
|
|
11,997,227
|
| Stock-based compensation |
|
21,160
|
|
|
21,160
|
| Tax benefit of stock-based compensation |
|
352,294
|
|
|
352,294
|
| Cash dividends declared |
|
|
|
(19,414,864)
|
(19,414,864)
|
| Exercise of stock options (in shares) |
18,090
|
|
|
|
|
| Exercise of stock options |
$ 181
|
292,728
|
|
|
292,909
|
| Balance (in shares) at Mar. 31, 2016 |
4,835,010
|
|
|
|
|
| Balance at Mar. 31, 2016 |
$ 48,350
|
19,205,682
|
451,359
|
79,559,196
|
99,264,587
|
| Exercise of stock options (in shares) |
6,000
|
|
|
|
|
| Exercise of stock options |
$ 60
|
247,050
|
|
|
247,110
|
| Comprehensive income: |
|
|
|
|
|
| Unrealized loss from marketable securities, net of tax |
|
|
(489,657)
|
|
(489,657)
|
| Net income |
|
|
|
12,948,869
|
12,948,869
|
| Total comprehensive income |
|
|
|
|
12,459,212
|
| Stock-based compensation |
|
22,000
|
|
|
22,000
|
| Tax benefit of stock-based compensation |
|
32,616
|
|
|
32,616
|
| Cash dividends declared |
|
|
|
(19,346,040)
|
(19,346,040)
|
| Exercise of stock options (in shares) |
6,000
|
|
|
|
|
| Exercise of stock options |
$ 60
|
247,050
|
|
|
247,110
|
| Balance (in shares) at Mar. 31, 2017 |
4,841,010
|
|
|
|
|
| Balance at Mar. 31, 2017 |
$ 48,410
|
19,507,348
|
(38,298)
|
73,162,025
|
92,679,485
|
| Exercise of stock options (in shares) |
1,000
|
|
|
|
|
| Exercise of stock options |
$ 10
|
51,030
|
|
|
51,040
|
| Comprehensive income: |
|
|
|
|
|
| Unrealized loss from marketable securities, net of tax |
|
|
(877,337)
|
|
(877,337)
|
| Net income |
|
|
|
13,912,672
|
13,912,672
|
| Total comprehensive income |
|
|
|
|
13,035,335
|
| Stock-based compensation |
|
40,920
|
|
|
40,920
|
| Cash dividends declared |
|
|
|
(19,365,040)
|
(19,365,040)
|
| Exercise of stock options (in shares) |
1,000
|
|
|
|
|
| Exercise of stock options |
$ 10
|
51,030
|
|
|
51,040
|
| Balance (in shares) at Mar. 31, 2018 |
4,842,010
|
|
|
|
|
| Balance at Mar. 31, 2018 |
$ 48,420
|
$ 19,599,298
|
$ (915,635)
|
$ 67,709,657
|
$ 86,441,740
|