Loans Receivable and Allowance for Credit Losses - Summary of Activities in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Allowance for loan losses
Allowance for loan losses, December 31, 2022					$ 595,645
Allowance for loan losses, start of period	$ 619,893	$ 545,685	$ 595,645	$ 541,579
Provision for (reversal of) credit losses on loans	24,025	12,469	42,545	24,721
Gross charge-offs	(9,755)	(1,146)	(11,792)	(12,779)
Gross recoveries	2,218	7,730	3,646	11,099
Total net (charge-offs) recoveries	(7,537)	6,584	(8,146)	(1,680)
Foreign currency translation adjustment	(981)	(1,468)	(672)	(1,350)
Allowance for loan losses, end of period	635,400	563,270	635,400	563,270
Commercial lending \| Commercial and industrial (“C&I”)
Allowance for loan losses
Allowance for loan losses, December 31, 2022					371,700
Allowance for loan losses, start of period	376,325	339,446		338,252
Provision for (reversal of) credit losses on loans	5,259	19,030	4,581	28,292
Gross charge-offs	(7,335)	(240)	(9,235)	(11,428)
Gross recoveries	2,065	6,514	3,276	9,516
Total net (charge-offs) recoveries	(5,270)	6,274	(5,959)	(1,912)
Foreign currency translation adjustment	(981)	(1,468)	(672)	(1,350)
Allowance for loan losses, end of period	375,333	363,282	375,333	363,282
Commercial lending \| CRE
Allowance for loan losses
Allowance for loan losses, December 31, 2022					149,864
Allowance for loan losses, start of period	155,067	147,104		150,940
Provision for (reversal of) credit losses on loans	15,685	(6,819)	20,361	(10,312)
Gross charge-offs	(2,366)	(671)	(2,372)	(1,069)
Gross recoveries	119	631	315	686
Total net (charge-offs) recoveries	(2,247)	(40)	(2,057)	(383)
Foreign currency translation adjustment	0	0	0	0
Allowance for loan losses, end of period	168,505	140,245	168,505	140,245
Commercial lending \| Residential loan \| Multifamily residential
Allowance for loan losses
Allowance for loan losses, December 31, 2022					23,373
Allowance for loan losses, start of period	24,526	24,176		14,400
Provision for (reversal of) credit losses on loans	(1,604)	1,976	(469)	11,633
Gross charge-offs	0	(8)	0	(9)
Gross recoveries	16	408	28	528
Total net (charge-offs) recoveries	16	400	28	519
Foreign currency translation adjustment	0	0	0	0
Allowance for loan losses, end of period	22,938	26,552	22,938	26,552
Commercial lending \| Construction and land
Allowance for loan losses
Allowance for loan losses, December 31, 2022					9,109
Allowance for loan losses, start of period	9,322	11,016		15,468
Provision for (reversal of) credit losses on loans	1,995	(4,338)	2,205	(8,844)
Gross charge-offs	0	0	0	0
Gross recoveries	8	4	11	58
Total net (charge-offs) recoveries	8	4	11	58
Foreign currency translation adjustment	0	0	0	0
Allowance for loan losses, end of period	11,325	6,682	11,325	6,682
Consumer lending \| Residential loan \| Single-family residential
Allowance for loan losses
Allowance for loan losses, December 31, 2022					35,564
Allowance for loan losses, start of period	48,007	18,210		17,160
Provision for (reversal of) credit losses on loans	3,501	3,461	15,943	4,387
Gross charge-offs	0	0	0	0
Gross recoveries	5	169	5	293
Total net (charge-offs) recoveries	5	169	5	293
Foreign currency translation adjustment	0	0	0	0
Allowance for loan losses, end of period	51,513	21,840	51,513	21,840
Consumer lending \| HELOCs
Allowance for loan losses
Allowance for loan losses, December 31, 2022					4,475
Allowance for loan losses, start of period	4,971	3,748		3,435
Provision for (reversal of) credit losses on loans	(444)	(339)	136	(40)
Gross charge-offs	(6)	(193)	(97)	(193)
Gross recoveries	5	4	11	18
Total net (charge-offs) recoveries	(1)	(189)	(86)	(175)
Foreign currency translation adjustment	0	0	0	0
Allowance for loan losses, end of period	4,526	3,220	4,526	3,220
Consumer lending \| Other consumer
Allowance for loan losses
Allowance for loan losses, December 31, 2022					1,560
Allowance for loan losses, start of period	1,675	1,985		1,924
Provision for (reversal of) credit losses on loans	(367)	(502)	(212)	(395)
Gross charge-offs	(48)	(34)	(88)	(80)
Gross recoveries	0	0	0	0
Total net (charge-offs) recoveries	(48)	(34)	(88)	(80)
Foreign currency translation adjustment	0	0	0	0
Allowance for loan losses, end of period	$ 1,260	$ 1,449	1,260	$ 1,449
Accounting Standards Update 2022-02
Allowance for loan losses
Impact of ASU 2022-02 adoption					6,028
Allowance for loan losses, start of period			$ (6,000)
Accounting Standards Update 2022-02 \| Commercial lending \| Commercial and industrial (“C&I”)
Allowance for loan losses
Impact of ASU 2022-02 adoption					5,683
Accounting Standards Update 2022-02 \| Commercial lending \| CRE
Allowance for loan losses
Impact of ASU 2022-02 adoption					337
Accounting Standards Update 2022-02 \| Commercial lending \| Residential loan \| Multifamily residential
Allowance for loan losses
Impact of ASU 2022-02 adoption					6
Accounting Standards Update 2022-02 \| Commercial lending \| Construction and land
Allowance for loan losses
Impact of ASU 2022-02 adoption					0
Accounting Standards Update 2022-02 \| Consumer lending \| Residential loan \| Single-family residential
Allowance for loan losses
Impact of ASU 2022-02 adoption					1
Accounting Standards Update 2022-02 \| Consumer lending \| HELOCs
Allowance for loan losses
Impact of ASU 2022-02 adoption					1
Accounting Standards Update 2022-02 \| Consumer lending \| Other consumer
Allowance for loan losses
Impact of ASU 2022-02 adoption					$ 0

Financing Receivable Allowance For Credit Loss Excluding Accrued Interest Before Impact of Adoption

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Financing Receivable Allowance For Credit Loss Excluding Accrued Interest Impact of Adoption

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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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Amount of foreign currency translation gain (loss) which decreases (increases) allowance for credit loss on financing receivable. Excludes net investment in lease.

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Amount, after recovery, of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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Amount of credit loss expense (reversal of expense) for financing receivable.

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