Debt - Mortgages and Other Notes Payable (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
$16.5 million 4.97% Note, due September 26, 2023
Debt Instrument [Line Items]
Debt Instrument, face amount	$ 16,500,000
Stated interest rate	4.97%
Notes Payable
Debt Instrument [Line Items]
Notes payable, gross	$ 15,402,000	$ 15,539,000
Less deferred financing costs, net of accumulated amortization	(91,000)	(105,000)
Total notes payable	15,311,000	15,434,000
Notes Payable \| $16.5 million 4.97% Note, due September 26, 2023
Debt Instrument [Line Items]
Notes payable, gross	$ 15,402,000	$ 15,539,000

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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