Loans and Allowance for Loan Losses, Modified Loans Payment Status (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 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
Non-homogeneous loans over	$ 150trst_NonHomogeneousLoansGreaterThan
Internal grading of non-homogeneous loans over	$ 250

Deferral period of all past due loans in accordance with the bankruptcy court order.

No definition available.

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

Minimum internal grading of non-homogeneous loans reviewed and individually graded based on credit risk.

No definition available.

Name:	trst_InternalGradingOfNonHomogeneousLoansOver
Namespace Prefix:	trst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Minimum non-homogeneous loans reviewed and individually graded based on credit risk.

No definition available.

Name:	trst_NonHomogeneousLoansGreaterThan
Namespace Prefix:	trst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

No definition available.

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

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

Name:	us-gaap_ReceivablesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration