v3.25.3

Investment Securities - Available-for-sale Securities, Gross Unrealized Loss Position (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Investment Securities [Abstract]
Less than 12 months - Fair Value	$ 31,757	$ 24,307
Less than 12 months - Gross Unrealized Loss	223	318
12 months or more - Fair Value	231,363	322,009
12 months or more - Gross Unrealized Loss	18,918	29,090
Total - Fair Value	263,120	346,316
Total - Gross Unrealized Loss	19,141	29,408
U. S. Government Sponsored Enterprises [Member]
Investment Securities [Abstract]
Less than 12 months - Fair Value	6,987	11,961
Less than 12 months - Gross Unrealized Loss	13	38
12 months or more - Fair Value	34,537	68,651
12 months or more - Gross Unrealized Loss	376	1,182
Total - Fair Value	41,524	80,612
Total - Gross Unrealized Loss	389	1,220
Mortgage-Backed Securities and Collateralized Mortgage Obligations - Residential [Member]
Investment Securities [Abstract]
Less than 12 months - Fair Value	0	12,346
Less than 12 months - Gross Unrealized Loss	0	280
12 months or more - Fair Value	184,496	194,636
12 months or more - Gross Unrealized Loss	17,734	26,126
Total - Fair Value	184,496	206,982
Total - Gross Unrealized Loss	17,734	26,406
Corporate Bonds [Member]
Investment Securities [Abstract]
Less than 12 months - Fair Value	24,770	0
Less than 12 months - Gross Unrealized Loss	210	0
12 months or more - Fair Value	0	44,581
12 months or more - Gross Unrealized Loss	0	452
Total - Fair Value	24,770	44,581
Total - Gross Unrealized Loss	210	452
Small Business Administration-Guaranteed Participation Securities [Member]
Investment Securities [Abstract]
Less than 12 months - Fair Value	0	0
Less than 12 months - Gross Unrealized Loss	0	0
12 months or more - Fair Value	12,330	14,141
12 months or more - Gross Unrealized Loss	808	1,330
Total - Fair Value	12,330	14,141
Total - Gross Unrealized Loss	$ 808	$ 1,330

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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TRUSTCO BANK CORP N Y 10-Q