Commitments and Contingencies - Commitment (Details) - Commitments to Extend Credit - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	$ 536,764	$ 312,272
REAL ESTATE LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	357,862	183,477
Commercial Real Estate
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	3,888	247
Construction and development
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	128,481	95,031
One-to-four-family
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	175,436	39,697
Home equity.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	49,419	47,880
Commercial/Multi-family
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	638	622
CONSUMER LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	22,664	22,176
COMMERCIAL BUSINESS LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	156,238	106,619
Commercial and industrial
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	104,939	72,731
Warehouse lending
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	$ 51,299	$ 33,888