Earnings Per Share - Schedule of Basic and Diluted Earnings Per Share (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Earnings Per Share [Abstract]
Net Income	$ 1,173,000	$ 791,000	$ 2,559,000	$ 2,032,000
Basic EPS	$ 1,173,000	$ 791,000	$ 2,559,000	$ 2,032,000
Basic EPS, shares	4,961,018	4,969,013	4,963,592	4,955,725
Basic EPS, per share	$ 0.24	$ 0.16	$ 0.52	$ 0.41
Effect of dilutive securities convertible preferred Stock
Effect of dilutive securities convertible preferred Stock, shares	20,500	20,500	20,500	20,500
Effect of dilutive securities convertible preferred Stock, per share
Diluted EPS	$ 1,173,000	$ 791,000	$ 2,559,000	$ 2,032,000
Diluted EPS, shares	4,981,518	4,989,513	4,984,092	4,976,225
Diluted EPS, per share	$ 0.24	$ 0.16	$ 0.51	$ 0.41