Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financial Assets:
Cash and cash equivalents	$ 89,107	$ 77,726
Loans held for sale	397	806
Loans receivable, net	980,317	862,394
Accrued interest receivable	3,140	3,068
Financial Liabilities:
Deposit	997,256	904,466
Accrued interest payable	2,541	1,715
Carrying Amount
Financial Assets:
Cash and cash equivalents	89,107	77,726
Loans held for sale	368	752
Loans receivable, net	954,730	865,423
Accrued interest receivable	3,140	3,068
Financial Liabilities:
Deposit	995,993	905,176
Accrued interest payable	2,541	1,715
Level 1
Financial Assets:
Cash and cash equivalents	89,107	77,726
Accrued interest receivable	19	44
Level 2
Financial Assets:
Loans held for sale	397	806
Accrued interest receivable	246	240
Financial Liabilities:
Deposit	997,256	904,466
Accrued interest payable	2,541	1,715
Level 3
Financial Assets:
Loans receivable, net	980,317	862,394
Accrued interest receivable	$ 2,875	$ 2,784