Commitments and Contingencies - Commitment (Details) - Commitments to Extend Credit - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	$ 312,272	$ 295,841
REAL ESTATE LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	183,477	160,158
Commercial
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	247	5,836
Construction and development
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	95,031	76,889
One-to-four-family
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	39,697	35,714
Home equity.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	47,880	41,204
Commercial/Multi-family
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	622	515
CONSUMER LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	22,176	18,560
COMMERCIAL BUSINESS LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	106,619	117,123
Commercial and industrial
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	72,731	72,880
Warehouse lending
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	$ 33,888	$ 44,243