Investment and Mortgage-Backed Securities, Available for Sale (Schedule of Available for Sale Securities) (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Gross Realized Losses	$ 8,000	$ 67,000
Available For Sale Securities Pledged as Collateral, Amortized Cost Basis	120,600,000		$ 111,800,000
Pledged Assets Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	121,400,000		111,700,000
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	398,638,123		386,296,513
Available-for-sale Securities, Gross Unrealized Gains	5,444,304		3,177,017
Available-for-sale Securities, Gross Unrealized Losses	1,730,735		3,217,693
Available-for-sale Securities, Fair Value Disclosure	402,351,692		386,255,837
Proceeds From Sale of Available For Sale Securities Including Mortgage Backed Securities	6,600,000	28,600,000
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	57,215,772		60,141,164
Available-for-sale Securities, Gross Unrealized Gains	2,614,780		1,518,974
Available-for-sale Securities, Gross Unrealized Losses	41,776		329,769
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	29,300,000		29,700,000
Available-for-sale Securities, Fair Value Disclosure	29,400,000
Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Gross Realized Gains	299,000	$ 503,000	20,713
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	23,106,586		12,934,037
Available-for-sale Securities, Gross Unrealized Losses	198,158		69,249
Available-for-sale Securities, Gross Realized Gains	3,230
SBA Bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	124,885,470		125,777,016
Available-for-sale Securities, Gross Unrealized Gains	601,258		560,352
Available-for-sale Securities, Gross Unrealized Losses	620,733		890,837
Mortgage-Backed Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	191,277,150		185,291,038
Available-for-sale Securities, Gross Unrealized Gains	2,203,203		1,073,432
Available-for-sale Securities, Gross Unrealized Losses	858,675		1,903,919
Equity Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	155,000		155,000
Available-for-sale Securities, Gross Unrealized Gains	0		0
Available-for-sale Securities, Gross Unrealized Losses	0		0
Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost of Investment And Mortgage-Backed Securities Available For Sale	1,998,145		1,998,258
Available-for-sale Securities, Gross Unrealized Gains	21,833		3,546
Available-for-sale Securities, Gross Unrealized Losses	11,393		23,919
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Fair Value Disclosure	59,788,776		61,330,369
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Fair Value Disclosure	22,911,658		12,885,501
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| SBA Bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Fair Value Disclosure	124,865,995		125,446,531
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Mortgage-Backed Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Fair Value Disclosure	192,621,678		184,460,551
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Equity Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Fair Value Disclosure	155,000		155,000
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Fair Value Disclosure	$ 2,008,585		$ 1,977,885

Available For Sale Securities Pledged as Collateral, Amortized Cost Basis

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Proceeds From Sale of Available For Sale Securities Including Mortgage Backed Securities

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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The fair value, as of the date of each statement of financial position presented, of other securities, classified as available for sale or held for investment, which are owned but transferred to serve as collateral for the payment of the related debt obligation, primarily a secured borrowing or repurchase agreement, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

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