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Loans - Narrative, Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) loan	Jun. 30, 2020 borrower contract	Jun. 30, 2021 USD ($) loan contract	Jun. 30, 2020 USD ($) borrower loan contract	Dec. 31, 2020 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of relationships (contract) | loan	0		0	3
Pre-Modification Outstanding Recorded Investment				$ 731
Post-Modification Outstanding Recorded Investment(1)				$ 731
Number of borrowers | borrower		3		3
Net loans held-for-investment	$ 3,777,780		$ 3,777,780		$ 3,785,631
Troubled debt restructurings	11,500		$ 11,500		$ 12,100
Number of TDR loans restructured that subsequently defaulted (contract) | contract			0	0
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of relationships (contract) | loan				1
Pre-Modification Outstanding Recorded Investment				$ 187
Post-Modification Outstanding Recorded Investment(1)				$ 187
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of relationships (contract) | loan				2
Pre-Modification Outstanding Recorded Investment				$ 544
Post-Modification Outstanding Recorded Investment(1)				$ 544
COVID-19
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of relationships (contract) | contract		4
Loan modification program, extension for payment deferral period			90 days
Loan modification program, payment deferral period			90 days
Non-TDR loan restructuring modifications (contracts) | loan			21
Net loans held-for-investment	21,500		$ 21,500
Deferred interest payback period, maximum			18 months
COVID-19 | Principal deferral (interest only)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-TDR loan restructuring modifications (contracts) | loan			6
Net loans held-for-investment	2,100		$ 2,100
COVID-19 | Deferrable notes
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-TDR loan restructuring modifications (contracts) | loan			15
Net loans held-for-investment	$ 19,400		$ 19,400

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