Balances at Other Banks (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Balances at Other Banks [Abstract]
Balances at Other Banks	$ 75.7	$ 67.1

Balance maintained with the Federal Reserve Bank to meet reserve requirements pursuant to Federal Banking Regulations.

No definition available.

Name:	trst_FederalReserveBankReserveRequirement
Namespace Prefix:	trst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant