Bank segment - Other Borrowings (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Offsetting Liabilities [Line Items]
Other bank borrowings	$ 520,000	$ 750,000
American Savings Bank (ASB)
Offsetting Liabilities [Line Items]
Advances from the FHLB	$ 520,000	$ 200,000

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 470
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478878/942-470-45-1

Name:	us-gaap_AdvancesFromFederalHomeLoanBanks
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant