Fair Value Measurements - Schedule of Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($)	Apr. 30, 2019	Apr. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	$ 27,291,000	$ 26,346,000
Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	5,483,000	5,741,000
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	26,000	131,000
REITs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	84,000	106,000
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	20,465,000	19,333,000
Money Markets and CDs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	1,233,000	1,035,000
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	21,724,000	20,499,000
Level 1 [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 1 [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	26,000	131,000
Level 1 [Member] | REITs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 1 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	20,465,000	19,333,000
Level 1 [Member] | Money Markets and CDs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	1,233,000	1,035,000
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	5,567,000	5,847,000
Level 2 [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	5,483,000	5,741,000
Level 2 [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 2 [Member] | REITs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis	84,000	106,000
Level 2 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 2 [Member] | Money Markets and CDs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 3 [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 3 [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 3 [Member] | REITs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis
Level 3 [Member] | Money Markets and CDs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets measured on a recurring basis