Investment Securities, Other-Than-Temporary-Impairment (Details)	Sep. 30, 2014 Security
Investment security impairment - Other Than Temporary Impairment [Abstract]
Number of securities in portfolio	187
Number of securities in portfolio in unrealized loss position	84

Number of securities in portfolio in an unrealized loss position.

No definition available.

Name:	trst_NumberOfSecuritiesInPortfolioInUnrealizedLossPosition
Namespace Prefix:	trst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant