Deposits - Time Certificate Denominations and Overdrawn Accounts (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Deposits.
Time certificates of deposit in denominations of $250,000 or more, in the aggregate	$ 1,400.0	$ 1,300.0
Overdrawn deposit accounts classified as loans	$ 3.8	$ 3.9

Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-SubTopic 405
-Topic 942
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478353/942-405-50-1

Name:	us-gaap_DepositLiabilitiesReclassifiedAsLoansReceivable1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant