Deposits (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Deposits [Abstract]
Amount included in time deposits with balance in excess of $250,000	$ 602.6	$ 561.3

The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $250,000 or more.

No definition available.

Name:	trst_AmountIncludedInTimeDepositsWithBalanceIn250000OrMore
Namespace Prefix:	trst_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant