Investment Securities - Net gains on trading securities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Investment Securities
Net gains on sales transaction	$ 204	$ 1,517	$ 1,605	$ 1,461
Net unrealized (losses) gains	(1,572)	(1)	(2,059)	410
Net (losses) gains on trading securities	$ (1,368)	$ 1,516	$ (454)	$ 1,871

Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-14

Name:	us-gaap_DebtSecuritiesTradingRealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration