Loans Receivable and Allowance for Credit Losses - Aging Analysis on Loans Held-for-Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	$ 50,907,184	$ 48,202,430
Total Nonaccrual Loans	103,700	99,526
Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	50,709,575	48,040,733
Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	93,909	62,171
Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	70,959	42,677
Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	22,950	19,494
Commercial lending
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	36,229,707	34,780,453
Total Nonaccrual Loans	65,578	73,841
Commercial lending | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	36,127,081	34,682,072
Commercial lending | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	37,048	24,540
Commercial lending | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	36,293	21,345
Commercial lending | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	755	3,195
Commercial lending | Commercial and industrial (“C&I”)
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	15,864,042	15,711,095
Total Nonaccrual Loans	49,147	50,428
Commercial lending | Commercial and industrial (“C&I”) | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	15,781,468	15,651,312
Commercial lending | Commercial and industrial (“C&I”) | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	33,427	9,355
Commercial lending | Commercial and industrial (“C&I”) | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	33,195	6,482
Commercial lending | Commercial and industrial (“C&I”) | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	232	2,873
Commercial lending | CRE
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	14,667,378	13,857,870
Total Nonaccrual Loans	610	23,244
Commercial lending | CRE | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	14,664,230	13,820,441
Commercial lending | CRE | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	2,538	14,185
Commercial lending | CRE | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	2,015	14,185
Commercial lending | CRE | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	523	0
Commercial lending | Real estate loan | Multifamily residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	4,900,097	4,573,068
Total Nonaccrual Loans	4,680	169
Commercial lending | Real estate loan | Current Accruing Loans | Multifamily residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	4,894,334	4,571,899
Commercial lending | Real estate loan | Total Accruing Past Due Loans | Multifamily residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	1,083	1,000
Commercial lending | Real estate loan | Accruing Loans 30-59 Days Past Due | Multifamily residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	1,083	678
Commercial lending | Real estate loan | Accruing Loans 60-89 Days Past Due | Multifamily residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	0	322
Commercial lending | Construction and land
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	798,190	638,420
Total Nonaccrual Loans	11,141	0
Commercial lending | Construction and land | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	787,049	638,420
Commercial lending | Construction and land | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	0	0
Commercial lending | Construction and land | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	0	0
Commercial lending | Construction and land | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	0	0
Commercial lending | Total CRE
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	20,365,665	19,069,358
Total Nonaccrual Loans	16,431	23,413
Commercial lending | Total CRE | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	20,345,613	19,030,760
Commercial lending | Total CRE | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	3,621	15,185
Commercial lending | Total CRE | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	3,098	14,863
Commercial lending | Total CRE | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	523	322
Consumer lending
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	14,677,477	13,421,977
Total Nonaccrual Loans	38,122	25,685
Consumer lending | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	14,582,494	13,358,661
Consumer lending | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	56,861	37,631
Consumer lending | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	34,666	21,332
Consumer lending | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	22,195	16,299
Consumer lending | Real estate loan | Single-family residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	12,836,558	11,223,027
Total Nonaccrual Loans	24,784	14,240
Consumer lending | Real estate loan | Current Accruing Loans | Single-family residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	12,771,661	11,183,134
Consumer lending | Real estate loan | Total Accruing Past Due Loans | Single-family residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	40,113	25,653
Consumer lending | Real estate loan | Accruing Loans 30-59 Days Past Due | Single-family residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	24,141	13,523
Consumer lending | Real estate loan | Accruing Loans 60-89 Days Past Due | Single-family residential
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	15,972	12,130
Consumer lending | HELOCs
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	1,776,665	2,122,655
Total Nonaccrual Loans	13,202	11,346
Consumer lending | HELOCs | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	1,746,841	2,102,523
Consumer lending | HELOCs | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	16,622	8,786
Consumer lending | HELOCs | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	10,416	7,700
Consumer lending | HELOCs | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	6,206	1,086
Consumer lending | Total residential mortgage
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	14,613,223	13,345,682
Total Nonaccrual Loans	37,986	25,586
Consumer lending | Total residential mortgage | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	14,518,502	13,285,657
Consumer lending | Total residential mortgage | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	56,735	34,439
Consumer lending | Total residential mortgage | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	34,557	21,223
Consumer lending | Total residential mortgage | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	22,178	13,216
Consumer lending | Other consumer
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	64,254	76,295
Total Nonaccrual Loans	136	99
Consumer lending | Other consumer | Current Accruing Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	63,992	73,004
Consumer lending | Other consumer | Total Accruing Past Due Loans
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	126	3,192
Consumer lending | Other consumer | Accruing Loans 30-59 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	109	109
Consumer lending | Other consumer | Accruing Loans 60-89 Days Past Due
Current, Past Due or Nonaccrual Loans
Financing receivable, excluding accrued interest, modified, after 12 months	$ 17	$ 3,083