Fair Value - Schedule of assets and liabilities measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial assets
Investment securities available for sale	$ 32,535	$ 0
Residential loans held for sale	91,243	208,704
SBA loans held for investment, at fair value	9,805	9,264
Fair Value, Recurring
Financial assets
Investment securities available for sale	32,535
Residential loans held for sale	91,243	208,704
SBA loans held for investment, at fair value	9,805	9,264
Fair Value, Recurring \| Interest rate lock commitments
Financial assets
Derivative assets	1,579	7,565
Financial liabilities
Derivative liabilities	335	12
Fair Value, Recurring \| Mandatory forward sales contracts
Financial assets
Derivative assets	1,004
Financial liabilities
Derivative liabilities	44	4,455
Fair Value, Recurring \| Best efforts forward sales contracts
Financial assets
Derivative assets	30	55
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets
Investment securities available for sale	0
Residential loans held for sale	28,798	21,888
SBA loans held for investment, at fair value	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Interest rate lock commitments
Financial assets
Derivative assets	0	0
Financial liabilities
Derivative liabilities	0	0
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Mandatory forward sales contracts
Financial assets
Derivative assets	1,004
Financial liabilities
Derivative liabilities	44	4,455
Fair Value, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Best efforts forward sales contracts
Financial assets
Derivative assets	0	0
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2)
Financial assets
Investment securities available for sale	32,535
Residential loans held for sale	62,445	186,816
SBA loans held for investment, at fair value	0	0
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Interest rate lock commitments
Financial assets
Derivative assets	0	0
Financial liabilities
Derivative liabilities	0	0
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Mandatory forward sales contracts
Financial assets
Derivative assets	0
Financial liabilities
Derivative liabilities	0	0
Fair Value, Recurring \| Significant Other Observable Inputs (Level 2) \| Best efforts forward sales contracts
Financial assets
Derivative assets	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3)
Financial assets
Investment securities available for sale	0
Residential loans held for sale	0	0
SBA loans held for investment, at fair value	9,805	9,264
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Interest rate lock commitments
Financial assets
Derivative assets	1,579	7,565
Financial liabilities
Derivative liabilities	335	12
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Mandatory forward sales contracts
Financial assets
Derivative assets	0
Financial liabilities
Derivative liabilities	0	0
Fair Value, Recurring \| Significant Unobservable Inputs (Level 3) \| Best efforts forward sales contracts
Financial assets
Derivative assets	$ 30	$ 55

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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