Loans Receivable and Allowance for Credit Losses - Allowance for Credit Losses Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) qtr	Jun. 30, 2023 USD ($) qtr	Jun. 30, 2024 USD ($) qtr	Jun. 30, 2023 USD ($) qtr	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 qtr	Mar. 31, 2023 USD ($)	Jan. 01, 2023 USD ($)	Dec. 31, 2022 USD ($)
Financing Receivable Allowance for Credit Losses
Life time loss rate, period span | qtr	8		8
Allowance for credit losses	$ 723,000		$ 723,000			$ 706,000
Increase in allowance for credit losses			17,000
Allowance for loan losses	683,794	$ 635,400	683,794	$ 635,400	$ 670,280	668,743		$ 619,893	$ 601,673	$ 595,645
Provision for (reversal of) credit losses on loans	36,762	24,025	60,916	42,545
Gross charge-offs	(25,322)	(9,755)	(50,006)	(11,792)
Gross recoveries	2,187	2,218	4,294	3,646
Net charge-offs	(23,135)	(7,537)	(45,712)	(8,146)
Foreign currency translation adjustment	(113)	$ (981)	(153)	$ (672)
C&I
Financing Receivable Allowance for Credit Losses
Life time loss rate, period span | qtr		11		11			8
C&I | Commercial lending
Financing Receivable Allowance for Credit Losses
Allowance for loan losses	379,984	$ 375,333	379,984	$ 375,333	373,631	392,685		376,325	377,383	371,700
Provision for (reversal of) credit losses on loans	17,783	5,259	18,057	4,581
Gross charge-offs	(13,134)	(7,335)	(34,132)	(9,235)
Gross recoveries	1,817	2,065	3,527	3,276
Net charge-offs	(11,317)	(5,270)	(30,605)	(5,959)
Foreign currency translation adjustment	(113)	(981)	(153)	(672)
Multifamily residential | Commercial lending
Financing Receivable Allowance for Credit Losses
Allowance for loan losses	40,254	22,938	40,254	22,938	$ 37,418	$ 34,375		$ 24,526	$ 23,379	$ 23,373
Provision for (reversal of) credit losses on loans	2,628	(1,604)	5,660	(469)
Gross charge-offs	0	0	(6)	0
Gross recoveries	208	16	225	28
Net charge-offs	208	16	219	28
Foreign currency translation adjustment	$ 0	$ 0	$ 0	$ 0