Loans Receivable and Allowance for Credit Losses (Aging Analysis on Loans Held-for-Investment) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	$ 113,150
Total Nonaccrual Loans	178,820
Current Accruing Loans	36,937,442
Total	37,229,412	$ 34,778,539
Accruing Loans 30-59  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	90,421
Accruing Loans 60-89  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	22,729
Nonaccrual Loans Less Than 90  Days Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	58,695
Nonaccrual Loans 90 or More Days  Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	120,125
Commercial lending
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	74,826
Total Nonaccrual Loans	142,174
Current Accruing Loans	27,707,906
Total	27,924,906	25,914,252
Commercial lending | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	60,136
Total Nonaccrual Loans	84,823
Current Accruing Loans	13,277,732
Total	13,422,691	12,150,931
Commercial lending | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	8,727
Total Nonaccrual Loans	56,577
Current Accruing Loans	10,836,810
Total	10,902,114	10,278,448
Commercial lending | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	5,963
Total Nonaccrual Loans	774
Current Accruing Loans	3,025,648
Total	3,032,385	2,856,374
Commercial lending | Construction and land
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	0
Total Nonaccrual Loans	0
Current Accruing Loans	567,716
Total	567,716	628,499
Commercial lending | Total CRE
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	14,690
Total Nonaccrual Loans	57,351
Current Accruing Loans	14,430,174
Total	14,502,215	13,763,321
Commercial lending | Accruing Loans 30-59  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	57,881
Commercial lending | Accruing Loans 30-59  Days Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	46,774
Commercial lending | Accruing Loans 30-59  Days Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	7,452
Commercial lending | Accruing Loans 30-59  Days Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	3,655
Commercial lending | Accruing Loans 30-59  Days Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	0
Commercial lending | Accruing Loans 30-59  Days Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	11,107
Commercial lending | Accruing Loans 60-89  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	16,945
Commercial lending | Accruing Loans 60-89  Days Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	13,362
Commercial lending | Accruing Loans 60-89  Days Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	1,275
Commercial lending | Accruing Loans 60-89  Days Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	2,308
Commercial lending | Accruing Loans 60-89  Days Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	0
Commercial lending | Accruing Loans 60-89  Days Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	3,583
Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	56,539
Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	54,555
Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	1,210
Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	774
Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	0
Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	1,984
Commercial lending | Nonaccrual Loans 90 or More Days  Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	85,635
Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	30,268
Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	55,367
Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	0
Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	0
Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	55,367
Consumer lending
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	38,324
Total Nonaccrual Loans	36,646
Current Accruing Loans	9,229,536
Total	9,304,506	8,864,287
Consumer lending | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	20,691
Total Nonaccrual Loans	20,070
Current Accruing Loans	7,619,333
Total	7,660,094	7,108,590
Consumer lending | HELOCs
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	2,938
Total Nonaccrual Loans	14,068
Current Accruing Loans	1,444,945
Total	1,461,951	1,472,783
Consumer lending | Total residential mortgage
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	23,629
Total Nonaccrual Loans	34,138
Current Accruing Loans	9,064,278
Total	9,122,045	8,581,373
Consumer lending | Other consumer
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	14,695
Total Nonaccrual Loans	2,508
Current Accruing Loans	165,258
Total	182,461	282,914
Consumer lending | Accruing Loans 30-59  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	32,540
Consumer lending | Accruing Loans 30-59  Days Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	15,739
Consumer lending | Accruing Loans 30-59  Days Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	2,165
Consumer lending | Accruing Loans 30-59  Days Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	17,904
Consumer lending | Accruing Loans 30-59  Days Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	14,636
Consumer lending | Accruing Loans 60-89  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	5,784
Consumer lending | Accruing Loans 60-89  Days Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	4,952
Consumer lending | Accruing Loans 60-89  Days Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	773
Consumer lending | Accruing Loans 60-89  Days Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	5,725
Consumer lending | Accruing Loans 60-89  Days Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans	59
Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	2,156
Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	1,713
Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	443
Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	2,156
Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	0
Consumer lending | Nonaccrual Loans 90 or More Days  Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	34,490
Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	18,357
Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	13,625
Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	31,982
Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Nonaccrual Loans	$ 2,508
Non-PCI Loans
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		101,283
Total Nonaccrual Loans		120,219
Current Accruing Loans		34,334,166
Total		34,555,668
Non-PCI Loans | Accruing Loans 30-59  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		73,871
Non-PCI Loans | Accruing Loans 60-89  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		27,412
Non-PCI Loans | Nonaccrual Loans Less Than 90  Days Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		35,570
Non-PCI Loans | Nonaccrual Loans 90 or More Days  Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		84,649
Non-PCI Loans | Commercial lending
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		73,691
Total Nonaccrual Loans		92,095
Current Accruing Loans		25,611,253
Total		25,777,039
Non-PCI Loans | Commercial lending | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		48,155
Total Nonaccrual Loans		74,835
Current Accruing Loans		12,026,131
Total		12,149,121
Non-PCI Loans | Commercial lending | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		24,807
Total Nonaccrual Loans		16,441
Current Accruing Loans		10,123,999
Total		10,165,247
Non-PCI Loans | Commercial lending | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		729
Total Nonaccrual Loans		819
Current Accruing Loans		2,832,664
Total		2,834,212
Non-PCI Loans | Commercial lending | Construction and land
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		0
Total Nonaccrual Loans		0
Current Accruing Loans		628,459
Total		628,459
Non-PCI Loans | Commercial lending | Total CRE
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		25,536
Total Nonaccrual Loans		17,260
Current Accruing Loans		13,585,122
Total		13,627,918
Non-PCI Loans | Commercial lending | Accruing Loans 30-59  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		54,149
Non-PCI Loans | Commercial lending | Accruing Loans 30-59  Days Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		31,121
Non-PCI Loans | Commercial lending | Accruing Loans 30-59  Days Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		22,830
Non-PCI Loans | Commercial lending | Accruing Loans 30-59  Days Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		198
Non-PCI Loans | Commercial lending | Accruing Loans 30-59  Days Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		0
Non-PCI Loans | Commercial lending | Accruing Loans 30-59  Days Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		23,028
Non-PCI Loans | Commercial lending | Accruing Loans 60-89  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		19,542
Non-PCI Loans | Commercial lending | Accruing Loans 60-89  Days Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		17,034
Non-PCI Loans | Commercial lending | Accruing Loans 60-89  Days Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		1,977
Non-PCI Loans | Commercial lending | Accruing Loans 60-89  Days Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		531
Non-PCI Loans | Commercial lending | Accruing Loans 60-89  Days Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		0
Non-PCI Loans | Commercial lending | Accruing Loans 60-89  Days Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		2,508
Non-PCI Loans | Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		32,158
Non-PCI Loans | Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		31,084
Non-PCI Loans | Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		540
Non-PCI Loans | Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		534
Non-PCI Loans | Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		0
Non-PCI Loans | Commercial lending | Nonaccrual Loans Less Than 90  Days Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		1,074
Non-PCI Loans | Commercial lending | Nonaccrual Loans 90 or More Days  Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		59,937
Non-PCI Loans | Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Commercial and industrial (“C&I”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		43,751
Non-PCI Loans | Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Commercial real estate (“CRE”)
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		15,901
Non-PCI Loans | Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Real estate loan | Multifamily residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		285
Non-PCI Loans | Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Construction and land
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		0
Non-PCI Loans | Commercial lending | Nonaccrual Loans 90 or More Days  Past Due | Total CRE
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		16,186
Non-PCI Loans | Consumer lending
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		27,592
Total Nonaccrual Loans		28,124
Current Accruing Loans		8,722,913
Total		8,778,629
Non-PCI Loans | Consumer lending | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		20,517
Total Nonaccrual Loans		14,865
Current Accruing Loans		6,993,597
Total		7,028,979
Non-PCI Loans | Consumer lending | HELOCs
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		7,064
Total Nonaccrual Loans		10,742
Current Accruing Loans		1,448,930
Total		1,466,736
Non-PCI Loans | Consumer lending | Total residential mortgage
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		27,581
Total Nonaccrual Loans		25,607
Current Accruing Loans		8,442,527
Total		8,495,715
Non-PCI Loans | Consumer lending | Other consumer
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		11
Total Nonaccrual Loans		2,517
Current Accruing Loans		280,386
Total		282,914
Non-PCI Loans | Consumer lending | Accruing Loans 30-59  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		19,722
Non-PCI Loans | Consumer lending | Accruing Loans 30-59  Days Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		15,443
Non-PCI Loans | Consumer lending | Accruing Loans 30-59  Days Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		4,273
Non-PCI Loans | Consumer lending | Accruing Loans 30-59  Days Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		19,716
Non-PCI Loans | Consumer lending | Accruing Loans 30-59  Days Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		6
Non-PCI Loans | Consumer lending | Accruing Loans 60-89  Days Past Due
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		7,870
Non-PCI Loans | Consumer lending | Accruing Loans 60-89  Days Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		5,074
Non-PCI Loans | Consumer lending | Accruing Loans 60-89  Days Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		2,791
Non-PCI Loans | Consumer lending | Accruing Loans 60-89  Days Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		7,865
Non-PCI Loans | Consumer lending | Accruing Loans 60-89  Days Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Accruing Past Due Loans		5
Non-PCI Loans | Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		3,412
Non-PCI Loans | Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		1,964
Non-PCI Loans | Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		1,448
Non-PCI Loans | Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		3,412
Non-PCI Loans | Consumer lending | Nonaccrual Loans Less Than 90  Days Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		0
Non-PCI Loans | Consumer lending | Nonaccrual Loans 90 or More Days  Past Due
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		24,712
Non-PCI Loans | Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | Real estate loan | Single-family residential
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		12,901
Non-PCI Loans | Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | HELOCs
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		9,294
Non-PCI Loans | Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | Total residential mortgage
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		22,195
Non-PCI Loans | Consumer lending | Nonaccrual Loans 90 or More Days  Past Due | Other consumer
Nonaccrual and Past Due Loans
Total Nonaccrual Loans		$ 2,517