Line of Credit, Promissory Notes Payable, Notes Payable, Advances, and Long-Term Debts - Future sinking fund contractual payments (Details)	12 Months Ended
	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	$ 33,000,000
2022
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	4,035,000
2023
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	1,265,000
2024
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	1,360,000
2025
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	1,455,000
2026 and thereafter
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	24,885,000
2016 Issue 2026 Series [Member]
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	7,535,000
2016 Issue 2026 Series [Member] | 2022
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	3,275,000
2016 Issue 2026 Series [Member] | 2023
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	965,000
2016 Issue 2026 Series [Member] | 2024
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	1,030,000
2016 Issue 2026 Series [Member] | 2025
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	1,095,000
2016 Issue 2026 Series [Member] | 2026 and thereafter
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	1,170,000
2016 Issue 2036 Series [Member]
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	17,465,000
2016 Issue 2036 Series [Member] | 2026 and thereafter
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	17,465,000
2018 Issue 2036 Series [Member]
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	8,000,000
2018 Issue 2036 Series [Member] | 2022
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	760,000
2018 Issue 2036 Series [Member] | 2023
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	300,000
2018 Issue 2036 Series [Member] | 2024
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	330,000
2018 Issue 2036 Series [Member] | 2025
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	360,000
2018 Issue 2036 Series [Member] | 2026 and thereafter
Debt Instrument [Line Items]
Debt Instrument, Sinking Fund Payment	$ 6,250,000