Fair Value - Fair Value - Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial Assets:
Securities available-for-sale	$ 17,494	$ 13,202
Carrying Value
Financial Assets:
Cash and cash equivalents	22,219	18,430
Securities available-for-sale	17,494	13,202
Loans receivable held for sale	22,370
Loans receivable held for investment	334,851	379,454
Accrued interest receivable	1,073	1,178
Federal Home Loan Bank stock	2,916	2,573
Financial Liabilities:
Deposits	291,290	287,427
Federal Home Loan Bank advances	65,000	85,000
Junior subordinated debentures	5,100	5,100
Accrued interest payable	304	154
Fair Value
Financial Assets:
Cash and cash equivalents	22,219	18,430
Securities available-for-sale	17,494	13,202
Loans receivable held for sale	22,626
Loans receivable held for investment	333,231	382,717
Accrued interest receivable	1,073	1,178
Federal Home Loan Bank stock	2,916	2,573
Financial Liabilities:
Deposits	280,761	278,254
Federal Home Loan Bank advances	64,887	85,748
Junior subordinated debentures	4,503	4,414
Accrued interest payable	304	154
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value
Financial Assets:
Cash and cash equivalents	22,219	18,430
Securities available-for-sale	1,976	1,988
Accrued interest receivable	58	64
Federal Home Loan Bank stock	2,916	2,573
Significant Other Observable Inputs (Level 2) | Fair Value
Financial Assets:
Securities available-for-sale	15,518	11,214
Loans receivable held for sale	22,626
Accrued interest receivable	91	29
Financial Liabilities:
Deposits	280,761	278,254
Federal Home Loan Bank advances	64,887	85,748
Accrued interest payable	296	147
Significant Unobservable Inputs (Level 3) | Fair Value
Financial Assets:
Loans receivable held for investment	333,231	382,717
Accrued interest receivable	924	1,085
Financial Liabilities:
Junior subordinated debentures	4,503	4,414
Accrued interest payable	$ 8	$ 7