Loans and Allowance for Loan Losses, Modified Loans Payment Status (Details)	9 Months Ended
Sep. 30, 2015
Loans and Allowance for Loan Losses [Abstract]
Deferral period of chapter 13 bankruptcies	60 months
Number of days past due when loans are considered to be in payment default	90 days
Contractual past due period for chapter 13 bankruptcy loans to be in payment default	30 days

Number of days past due when loan is considered to be in payment default under the modified terms.

No definition available.

Name:	trst_NumberOfDaysPastDueWhenLoansConsideredInPaymentDefaultUnderModifiedTerms
Namespace Prefix:	trst_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration