Loans Receivable and Allowance for Credit Losses (Aging Analysis on Loans Held-for-Investment) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	$ 93,181	$ 215,154
Total loans	41,693,781	38,390,955
Commercial Lending
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	68,965	184,153
Total loans	30,327,746	28,440,027
Commercial Lending | C&I
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	59,023	133,939
Total loans	14,150,608	13,631,726
Commercial Lending | CRE
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	9,498	46,546
Total loans	12,155,047	11,174,611
Commercial Lending | Residential loan | Multifamily
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	444	3,668
Total loans	3,675,605	3,033,998
Commercial Lending | Construction and land
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	0	0
Total loans	346,486	599,692
Commercial Lending | Total CRE
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	9,942	50,214
Total loans	16,177,138	14,808,301
Consumer Lending
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	24,216	31,001
Total loans	11,366,035	9,950,928
Consumer Lending | Residential loan | Single-family
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	15,720	16,814
Total loans	9,093,702	8,185,953
Consumer Lending | HELOCs
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	8,444	11,696
Total loans	2,144,821	1,601,716
Consumer Lending | Total residential mortgage
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	24,164	28,510
Total loans	11,238,523	9,787,669
Consumer Lending | Other consumer
Nonaccrual and Past Due Loans
Financing receivable, nonaccrual	52	2,491
Total loans	127,512	163,259
Current Accruing Loans
Nonaccrual and Past Due Loans
Total loans	41,555,745	38,125,211
Current Accruing Loans | Commercial Lending
Nonaccrual and Past Due Loans
Total loans	30,238,648	28,224,064
Current Accruing Loans | Commercial Lending | C&I
Nonaccrual and Past Due Loans
Total loans	14,080,516	13,488,070
Current Accruing Loans | Commercial Lending | CRE
Nonaccrual and Past Due Loans
Total loans	12,141,827	11,127,690
Current Accruing Loans | Commercial Lending | Residential loan | Multifamily
Nonaccrual and Past Due Loans
Total loans	3,669,819	3,028,512
Current Accruing Loans | Commercial Lending | Construction and land
Nonaccrual and Past Due Loans
Total loans	346,486	579,792
Current Accruing Loans | Commercial Lending | Total CRE
Nonaccrual and Past Due Loans
Total loans	16,158,132	14,735,994
Current Accruing Loans | Consumer Lending
Nonaccrual and Past Due Loans
Total loans	11,317,097	9,901,147
Current Accruing Loans | Consumer Lending | Residential loan | Single-family
Nonaccrual and Past Due Loans
Total loans	9,059,222	8,156,645
Current Accruing Loans | Consumer Lending | HELOCs
Nonaccrual and Past Due Loans
Total loans	2,130,523	1,583,968
Current Accruing Loans | Consumer Lending | Total residential mortgage
Nonaccrual and Past Due Loans
Total loans	11,189,745	9,740,613
Current Accruing Loans | Consumer Lending | Other consumer
Nonaccrual and Past Due Loans
Total loans	127,352	160,534
Accruing Loans 30-59  Days Past Due
Nonaccrual and Past Due Loans
Total loans	31,091	44,136
Accruing Loans 30-59  Days Past Due | Commercial Lending
Nonaccrual and Past Due Loans
Total loans	16,025	31,086
Accruing Loans 30-59  Days Past Due | Commercial Lending | C&I
Nonaccrual and Past Due Loans
Total loans	6,983	8,993
Accruing Loans 30-59  Days Past Due | Commercial Lending | CRE
Nonaccrual and Past Due Loans
Total loans	3,722	375
Accruing Loans 30-59  Days Past Due | Commercial Lending | Residential loan | Multifamily
Nonaccrual and Past Due Loans
Total loans	5,320	1,818
Accruing Loans 30-59  Days Past Due | Commercial Lending | Construction and land
Nonaccrual and Past Due Loans
Total loans	0	19,900
Accruing Loans 30-59  Days Past Due | Commercial Lending | Total CRE
Nonaccrual and Past Due Loans
Total loans	9,042	22,093
Accruing Loans 30-59  Days Past Due | Consumer Lending
Nonaccrual and Past Due Loans
Total loans	15,066	13,050
Accruing Loans 30-59  Days Past Due | Consumer Lending | Residential loan | Single-family
Nonaccrual and Past Due Loans
Total loans	10,191	9,911
Accruing Loans 30-59  Days Past Due | Consumer Lending | HELOCs
Nonaccrual and Past Due Loans
Total loans	4,776	2,922
Accruing Loans 30-59  Days Past Due | Consumer Lending | Total residential mortgage
Nonaccrual and Past Due Loans
Total loans	14,967	12,833
Accruing Loans 30-59  Days Past Due | Consumer Lending | Other consumer
Nonaccrual and Past Due Loans
Total loans	99	217
Accruing Loans 60-89  Days Past Due
Nonaccrual and Past Due Loans
Total loans	13,764	6,454
Accruing Loans 60-89  Days Past Due | Commercial Lending
Nonaccrual and Past Due Loans
Total loans	4,108	724
Accruing Loans 60-89  Days Past Due | Commercial Lending | C&I
Nonaccrual and Past Due Loans
Total loans	4,086	724
Accruing Loans 60-89  Days Past Due | Commercial Lending | CRE
Nonaccrual and Past Due Loans
Total loans	0	0
Accruing Loans 60-89  Days Past Due | Commercial Lending | Residential loan | Multifamily
Nonaccrual and Past Due Loans
Total loans	22	0
Accruing Loans 60-89  Days Past Due | Commercial Lending | Construction and land
Nonaccrual and Past Due Loans
Total loans	0	0
Accruing Loans 60-89  Days Past Due | Commercial Lending | Total CRE
Nonaccrual and Past Due Loans
Total loans	22	0
Accruing Loans 60-89  Days Past Due | Consumer Lending
Nonaccrual and Past Due Loans
Total loans	9,656	5,730
Accruing Loans 60-89  Days Past Due | Consumer Lending | Residential loan | Single-family
Nonaccrual and Past Due Loans
Total loans	8,569	2,583
Accruing Loans 60-89  Days Past Due | Consumer Lending | HELOCs
Nonaccrual and Past Due Loans
Total loans	1,078	3,130
Accruing Loans 60-89  Days Past Due | Consumer Lending | Total residential mortgage
Nonaccrual and Past Due Loans
Total loans	9,647	5,713
Accruing Loans 60-89  Days Past Due | Consumer Lending | Other consumer
Nonaccrual and Past Due Loans
Total loans	9	17
Total Accruing Past Due Loans
Nonaccrual and Past Due Loans
Total loans	44,855	50,590
Total Accruing Past Due Loans | Commercial Lending
Nonaccrual and Past Due Loans
Total loans	20,133	31,810
Total Accruing Past Due Loans | Commercial Lending | C&I
Nonaccrual and Past Due Loans
Total loans	11,069	9,717
Total Accruing Past Due Loans | Commercial Lending | CRE
Nonaccrual and Past Due Loans
Total loans	3,722	375
Total Accruing Past Due Loans | Commercial Lending | Residential loan | Multifamily
Nonaccrual and Past Due Loans
Total loans	5,342	1,818
Total Accruing Past Due Loans | Commercial Lending | Construction and land
Nonaccrual and Past Due Loans
Total loans	0	19,900
Total Accruing Past Due Loans | Commercial Lending | Total CRE
Nonaccrual and Past Due Loans
Total loans	9,064	22,093
Total Accruing Past Due Loans | Consumer Lending
Nonaccrual and Past Due Loans
Total loans	24,722	18,780
Total Accruing Past Due Loans | Consumer Lending | Residential loan | Single-family
Nonaccrual and Past Due Loans
Total loans	18,760	12,494
Total Accruing Past Due Loans | Consumer Lending | HELOCs
Nonaccrual and Past Due Loans
Total loans	5,854	6,052
Total Accruing Past Due Loans | Consumer Lending | Total residential mortgage
Nonaccrual and Past Due Loans
Total loans	24,614	18,546
Total Accruing Past Due Loans | Consumer Lending | Other consumer
Nonaccrual and Past Due Loans
Total loans	$ 108	$ 234