Loans Receivable and Allowance for Credit Losses - Schedule Of Activity In The Allowance For Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Allowance for loan losses
ALLL, beginning of period	$ 760,416	$ 683,794	$ 702,052	$ 668,743	$ 668,743
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	18,175		18,175
Provision for (reversal of) credit losses on loans	29,916	41,717	118,134	102,633
Gross charge-offs	(25,403)	(30,298)	(58,850)	(80,304)
Gross recoveries	7,263	935	10,778	5,229
Total net (charge-offs) recoveries	(18,140)	(29,363)	(48,072)	(75,075)
Foreign currency translation adjustment	153	337	231	184
ALLL, end of period	790,520	696,485	790,520	696,485	702,052
Commercial lending | C&I
Allowance for loan losses
ALLL, beginning of period	442,291	379,984	384,319	392,685	392,685
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	18,175		18,175
Provision for (reversal of) credit losses on loans	(992)	26,416	62,973	44,473
Gross charge-offs	(25,325)	(29,260)	(34,464)	(63,392)
Gross recoveries	7,236	838	10,304	4,365
Total net (charge-offs) recoveries	(18,089)	(28,422)	(24,160)	(59,027)
Foreign currency translation adjustment	153	337	231	184
ALLL, end of period	441,538	378,315	441,538	378,315	384,319
Commercial lending | CRE
Allowance for loan losses
ALLL, beginning of period	212,618	194,794	218,677	170,592	170,592
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	0		0
Provision for (reversal of) credit losses on loans	14,552	27,123	30,664	64,542
Gross charge-offs	(5)	(734)	(22,248)	(14,235)
Gross recoveries	2	61	74	345
Total net (charge-offs) recoveries	(3)	(673)	(22,174)	(13,890)
Foreign currency translation adjustment	0	0	0	0
ALLL, end of period	227,167	221,244	227,167	221,244	218,677
Commercial lending | Multifamily Residential
Allowance for loan losses
ALLL, beginning of period	29,073	40,254	32,117	34,375	34,375
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	0		0
Provision for (reversal of) credit losses on loans	6,101	(8,493)	3,028	(2,833)
Gross charge-offs	0	0	(7)	(6)
Gross recoveries	13	21	49	246
Total net (charge-offs) recoveries	13	21	42	240
Foreign currency translation adjustment	0	0	0	0
ALLL, end of period	35,187	31,782	35,187	31,782	32,117
Commercial lending | Land and construction
Allowance for loan losses
ALLL, beginning of period	17,856	14,322	17,497	10,469	10,469
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	0		0
Provision for (reversal of) credit losses on loans	671	(1,975)	3,020	3,828
Gross charge-offs	0	(145)	(1,996)	(2,289)
Gross recoveries	3	6	9	200
Total net (charge-offs) recoveries	3	(139)	(1,987)	(2,089)
Foreign currency translation adjustment	0	0	0	0
ALLL, end of period	18,530	12,208	18,530	12,208	17,497
Consumer lending | Single-Family Residential
Allowance for loan losses
ALLL, beginning of period	51,997	49,523	44,816	55,018	55,018
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	0		0
Provision for (reversal of) credit losses on loans	8,873	(1,293)	16,009	(6,760)
Gross charge-offs	0	0	(9)	(35)
Gross recoveries	6	1	60	8
Total net (charge-offs) recoveries	6	1	51	(27)
Foreign currency translation adjustment	0	0	0	0
ALLL, end of period	60,876	48,231	60,876	48,231	44,816
Consumer lending | HELOCs
Allowance for loan losses
ALLL, beginning of period	5,256	3,340	3,132	3,947	3,947
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	0		0
Provision for (reversal of) credit losses on loans	854	(128)	2,962	(792)
Gross charge-offs	0	(10)	0	(10)
Gross recoveries	3	8	19	65
Total net (charge-offs) recoveries	3	(2)	19	55
Foreign currency translation adjustment	0	0	0	0
ALLL, end of period	6,113	3,210	6,113	3,210	3,132
Consumer lending | Other Consumer
Allowance for loan losses
ALLL, beginning of period	1,325	1,577	1,494	1,657	1,657
Allowance recognized on purchased credit-deteriorated (“PCD”) loans	0		0
Provision for (reversal of) credit losses on loans	(143)	67	(522)	175
Gross charge-offs	(73)	(149)	(126)	(337)
Gross recoveries	0	0	263	0
Total net (charge-offs) recoveries	(73)	(149)	137	(337)
Foreign currency translation adjustment	0	0	0	0
ALLL, end of period	$ 1,109	$ 1,495	$ 1,109	$ 1,495	$ 1,494