Loans Receivable, Including Loans Held For Sale - Outstanding Loans (Accruing and Nonaccruing) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Receivable [Line Items]
Total loans	$ 2,552,237	$ 554,722
Commercial real estate loans
Receivable [Line Items]
Total loans	644	659
Commercial and industrial
Receivable [Line Items]
Total loans	2,372,454	251,349
Consumer loans
Receivable [Line Items]
Total loans	179,139	302,714
Non-Graded
Receivable [Line Items]
Total loans	393,364	537,274
Non-Graded | Commercial real estate loans
Receivable [Line Items]
Total loans	0	0
Non-Graded | Commercial and industrial
Receivable [Line Items]
Total loans	214,225	234,560
Non-Graded | Consumer loans
Receivable [Line Items]
Total loans	179,139	302,714
Pass
Receivable [Line Items]
Total loans	2,153,773	14,730
Pass | Commercial real estate loans
Receivable [Line Items]
Total loans	633	647
Pass | Commercial and industrial
Receivable [Line Items]
Total loans	2,153,140	14,083
Pass | Consumer loans
Receivable [Line Items]
Total loans	0	0
Special Mention
Receivable [Line Items]
Total loans	3,478	0
Special Mention | Commercial real estate loans
Receivable [Line Items]
Total loans	0	0
Special Mention | Commercial and industrial
Receivable [Line Items]
Total loans	3,478	0
Special Mention | Consumer loans
Receivable [Line Items]
Total loans	0	0
Sub- standard
Receivable [Line Items]
Total loans	1,622	2,718
Sub- standard | Commercial real estate loans
Receivable [Line Items]
Total loans	11	12
Sub- standard | Commercial and industrial
Receivable [Line Items]
Total loans	1,611	2,706
Sub- standard | Consumer loans
Receivable [Line Items]
Total loans	0	0
Doubtful
Receivable [Line Items]
Total loans	0	0
Doubtful | Commercial real estate loans
Receivable [Line Items]
Total loans	0	0
Doubtful | Commercial and industrial
Receivable [Line Items]
Total loans	0	0
Doubtful | Consumer loans
Receivable [Line Items]
Total loans	$ 0	$ 0