Loans Held for Investment - Delinquencies (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Loans held for investment	$ 14,676,298	$ 14,295,897
Loans held for investment before basis adjustment	14,738,224
Basis adjustment associated with fair value hedge
Financing Receivable, Past Due [Line Items]
Loans held for investment before basis adjustment	14,738,224	14,295,897
Basis adjustment associated with fair value hedge	(61,926)	0
Current
Financing Receivable, Past Due [Line Items]
Loans held for investment	14,694,876	14,276,402
30-59
Financing Receivable, Past Due [Line Items]
Loans held for investment	20,538	1,395
60-89
Financing Receivable, Past Due [Line Items]
Loans held for investment	185	0
90+
Financing Receivable, Past Due [Line Items]
Loans held for investment	22,625	18,100
Investor loans secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	9,213,516	8,987,628
Investor loans secured by real estate | CRE non-owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,660,321	2,771,137
Investor loans secured by real estate | Multifamily
Financing Receivable, Past Due [Line Items]
Loans held for investment	6,112,026	5,891,934
Investor loans secured by real estate | Construction and land
Financing Receivable, Past Due [Line Items]
Loans held for investment	399,034	277,640
Investor loans secured by real estate | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	42,135	46,917
Investor loans secured by real estate | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment	9,200,307	8,975,806
Investor loans secured by real estate | Current | CRE non-owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,655,892	2,760,882
Investor loans secured by real estate | Current | Multifamily
Financing Receivable, Past Due [Line Items]
Loans held for investment	6,103,246	5,890,704
Investor loans secured by real estate | Current | Construction and land
Financing Receivable, Past Due [Line Items]
Loans held for investment	399,034	277,640
Investor loans secured by real estate | Current | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	42,135	46,580
Investor loans secured by real estate | 30-59
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,723	1,230
Investor loans secured by real estate | 30-59 | CRE non-owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 30-59 | Multifamily
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,723	1,230
Investor loans secured by real estate | 30-59 | Construction and land
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 30-59 | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 60-89
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 60-89 | CRE non-owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 60-89 | Multifamily
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 60-89 | Construction and land
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 60-89 | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 90+
Financing Receivable, Past Due [Line Items]
Loans held for investment	10,486	10,592
Investor loans secured by real estate | 90+ | CRE non-owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	4,429	10,255
Investor loans secured by real estate | 90+ | Multifamily
Financing Receivable, Past Due [Line Items]
Loans held for investment	6,057	0
Investor loans secured by real estate | 90+ | Construction and land
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Investor loans secured by real estate | 90+ | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	337
Business loans secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,871,588	2,700,579
Business loans secured by real estate | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	61,368	69,184
Business loans secured by real estate | CRE owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,432,163	2,251,014
Business loans secured by real estate | Franchise real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	378,057	380,381
Business loans secured by real estate | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,855,335	2,695,186
Business loans secured by real estate | Current | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	60,177	68,743
Business loans secured by real estate | Current | CRE owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,424,174	2,246,062
Business loans secured by real estate | Current | Franchise real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	370,984	380,381
Business loans secured by real estate | 30-59
Financing Receivable, Past Due [Line Items]
Loans held for investment	8,507	0
Business loans secured by real estate | 30-59 | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Business loans secured by real estate | 30-59 | CRE owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	1,434	0
Business loans secured by real estate | 30-59 | Franchise real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	7,073	0
Business loans secured by real estate | 60-89
Financing Receivable, Past Due [Line Items]
Loans held for investment	104	0
Business loans secured by real estate | 60-89 | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	104	0
Business loans secured by real estate | 60-89 | CRE owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Business loans secured by real estate | 60-89 | Franchise real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Business loans secured by real estate | 90+
Financing Receivable, Past Due [Line Items]
Loans held for investment	7,642	5,393
Business loans secured by real estate | 90+ | SBA secured by real estate
Financing Receivable, Past Due [Line Items]
Loans held for investment	1,087	441
Business loans secured by real estate | 90+ | CRE owner-occupied
Financing Receivable, Past Due [Line Items]
Loans held for investment	6,555	4,952
Business loans secured by real estate | 90+ | Franchise real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Commercial loans
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,576,839	2,506,733
Commercial loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,160,948	2,103,112
Commercial loans | Franchise non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	404,791	392,576
Commercial loans | SBA non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	11,100	11,045
Commercial loans | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,564,012	2,504,453
Commercial loans | Current | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans held for investment	2,152,302	2,101,558
Commercial loans | Current | Franchise non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	401,199	392,576
Commercial loans | Current | SBA non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	10,511	10,319
Commercial loans | 30-59
Financing Receivable, Past Due [Line Items]
Loans held for investment	8,249	165
Commercial loans | 30-59 | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans held for investment	4,657	92
Commercial loans | 30-59 | Franchise non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,592	0
Commercial loans | 30-59 | SBA non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	73
Commercial loans | 60-89
Financing Receivable, Past Due [Line Items]
Loans held for investment	81	0
Commercial loans | 60-89 | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans held for investment	81	0
Commercial loans | 60-89 | Franchise non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Commercial loans | 60-89 | SBA non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Commercial loans | 90+
Financing Receivable, Past Due [Line Items]
Loans held for investment	4,497	2,115
Commercial loans | 90+ | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,908	1,462
Commercial loans | 90+ | Franchise non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Commercial loans | 90+ | SBA non-real estate secured
Financing Receivable, Past Due [Line Items]
Loans held for investment	589	653
Retail loans
Financing Receivable, Past Due [Line Items]
Loans held for investment	76,281	100,957
Retail loans | Single family residential
Financing Receivable, Past Due [Line Items]
Loans held for investment	72,997	95,292
Retail loans | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,284	5,665
Retail loans | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment	75,222	100,957
Retail loans | Current | Single family residential
Financing Receivable, Past Due [Line Items]
Loans held for investment	71,940	95,292
Retail loans | Current | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment	3,282	5,665
Retail loans | 30-59
Financing Receivable, Past Due [Line Items]
Loans held for investment	1,059	0
Retail loans | 30-59 | Single family residential
Financing Receivable, Past Due [Line Items]
Loans held for investment	1,057	0
Retail loans | 30-59 | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment	2	0
Retail loans | 60-89
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Retail loans | 60-89 | Single family residential
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Retail loans | 60-89 | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Retail loans | 90+
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Retail loans | 90+ | Single family residential
Financing Receivable, Past Due [Line Items]
Loans held for investment	0	0
Retail loans | 90+ | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment	$ 0	$ 0