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Fair Value - Financial Assets Accounted for at Fair Value (Details) | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2019 USD ($) | Jun. 30, 2018 USD ($) | Jun. 30, 2019 USD ($) | Jun. 30, 2018 USD ($) | Dec. 31, 2018 USD ($) | Mar. 31, 2019 USD ($) | Mar. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | $ 0 |  | $ 0 |  | $ 27,000 |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 87,080,000 |  | 87,080,000 |  | 88,179,000 |  |  |
Real Estate Acquired Through Foreclosure Fair Value |  |  |  |  | 1,000 |  |  |
Real Estate Owned, Valuation Allowance, Valuation Increase | 21,000 | $ 1,000 | 21,000 | $ 26,000 |  |  |  |
Other real estate owned at carrying value before valuation allowance | 518,000 |  | 518,000 |  | 1,249,000 |  |  |
Real Estate Owned, Valuation Allowance | 21,000 | $ 44,000 | 21,000 | $ 44,000 | 23,000 | $ 0 | $ 321,000 | $ 305,000
Certificates of deposit [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 73,523,000 |  | 73,523,000 |  | 73,507,000 |  |  |
Equity Funds [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Residential Mortgage Backed Securities [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 9,706,000 |  | 9,706,000 |  | 10,478,000 |  |  |
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value | 9,706,000 |  | 9,706,000 |  |  |  |  |
Collateralized Debt Obligations [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 3,337,000 |  | 3,337,000 |  | 3,685,000 |  |  |
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value | 3,337,000 |  | 3,337,000 |  |  |  |  |
Municipal Bonds [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 514,000 |  | 514,000 |  | 509,000 |  |  |
Nonrecurring [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 87,080,000 |  | 87,080,000 |  | 88,179,000 |  |  |
Nonrecurring [Member] | Certificates of deposit [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 73,523,000 |  | 73,523,000 |  | 73,507,000 |  |  |
Nonrecurring [Member] | Mortgage-backed securities - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 9,706,000 |  | 9,706,000 |  | 10,478,000 |  |  |
Nonrecurring [Member] | Collateralized mortgage obligations - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 3,337,000 |  | 3,337,000 |  | 3,685,000 |  |  |
Nonrecurring [Member] | Municipal Securities [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 514,000 |  | 514,000 |  | 509,000 |  |  |
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Certificates of deposit [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage-backed securities - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Collateralized mortgage obligations - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Municipal Securities [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 87,080,000 |  | 87,080,000 |  | 88,179,000 |  |  |
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Certificates of deposit [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 73,523,000 |  | 73,523,000 |  |  |  |  |
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Mortgage-backed securities - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value | 9,706,000 |  | 9,706,000 |  |  |  |  |
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Collateralized mortgage obligations - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value | 3,337,000 |  | 3,337,000 |  |  |  |  |
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Certificates of deposit [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage-backed securities - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Collateralized mortgage obligations - residential [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Municipal Securities [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Total Fair value | 0 |  | 0 |  | 0 |  |  |
One to Four Family Residential Real Estate Loans [Member] |  |  |  |  |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | 0 |  | 0 |  | 0 |  |  |
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value | 210,000 |  | 210,000 |  |  |  |  |
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value | 0 |  | 0 |  |  |  |  |
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value | 0 |  | 0 |  |  |  |  |
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value | 210,000 |  | 210,000 |  |  |  |  |
Commercial Real Estate [Member] |  |  |  |  |  |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | $ 0 |  | $ 0 |  | 27,000 |  |  |
Impaired Financing Receivable, with Related Allowance, Recorded Investment |  |  |  |  | 270,000 |  |  |
Land Loans [Member] | Nonrecurring [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value |  |  |  |  | 1,000 |  |  |
Land Loans [Member] | Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value |  |  |  |  | 0 |  |  |
Land Loans [Member] | Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value |  |  |  |  | 0 |  |  |
Land Loans [Member] | Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real Estate Acquired Through Foreclosure Fair Value |  |  |  |  | $ 1,000 |  |  |
Sales Comparison Valuation Technique [Member] | Real Estate [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Fair Value Measurements, Valuation Processes, Description |  |  | Sales comparison |  | Sales comparison |  |  |
Sales Comparison Valuation Technique [Member] | One to Four Family Residential Real Estate Loans [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Fair Value Measurements, Sensitivity Analysis, Description |  |  | Discount applied to valuation |  | Discount applied to valuation |  |  |
Impaired Loans [Member] | Sales Comparison Valuation Technique [Member] | Land Loans [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real estate owned, measurement input | 0.108 |  | 0.108 |  | 0.123 |  |  |
Measurement Input, Comparability Adjustment [Member] | Maximum [Member] | Real Estate Properties [Domain] | Nonresidential Real Estate [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real estate owned, measurement input |  |  |  |  | 0.1522 |  |  |
Measurement Input, Comparability Adjustment [Member] | Weighted Average [Member] | Real Estate Properties [Domain] | Nonresidential Real Estate [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Real estate owned, measurement input |  |  |  |  | 0.1100 |  |  |
Land [Member] |  |  |  |  |  |  |  |
Schedule of Company's financial instruments measured at fair values |  |  |  |  |  |  |  |
Other real estate owned at carrying value before valuation allowance | $ 0 |  | $ 0 |  | $ 24,000 |  |  |
Real Estate Owned, Valuation Allowance | $ 0 |  | $ 0 |  | $ 23,000 |  |  |

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Data Type: | na
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