Regulatory Capital Requirements (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Tier One Risk Based Capital [Abstract]
Tier One Risk Based Capital	$ 356,687	$ 340,456
Total risk-based capital	383,678	367,382
Risk Based Ratios [Abstract]
Tier 1 risk-based capital, ratio (in hundredths)	16.68%	15.97%
Total risk-based capital, ratio (in hundredths)	17.94%	17.23%
Leverage Capital [Abstract]
Leverage Capital	356,687	340,456
Tier One Risk Based Capital	356,687	340,456
Total risk-based capital	383,678	367,382
Leverage Ratios [Abstract]
Leverage Capital, ratio (in hundredths)	8.21%	8.14%
Tier 1 risk-based capital, ratio (in hundredths)	16.68%	15.97%
Total risk-based capital, ratio (in hundredths)	17.94%	17.23%
Leverage ratio for the most highly rated institutions (in hundredths)	3.00%
Trustco Bank [Member]
Tier One Risk Based Capital [Abstract]
Tier 1 (core) capital	349,580	335,759
Tier One Risk Based Capital	349,580	335,759
Total risk-based capital	376,565	362,648
Risk Based Ratios [Abstract]
Tier 1 (core) capital, ratio (in hundredths)	8.05%	7.90%
Tier 1 (core) capital, Well Capitalized (in hundredths)	5.00%	5.00%
Tier 1 (core) capital, Adequately Capitalized (in hundredths)	4.00%	4.00%
Tier 1 risk-based capital, ratio (in hundredths)	16.35%	15.75%
Tier 1 risk-based capital, Well Capitalized (in hundredths)	6.00%	6.00%
Tier 1 risk-based capital, Adequately Capitalized (in hundredths)	4.00%	4.00%
Total risk-based capital, ratio (in hundredths)	17.62%	17.01%
Total risk-based capital, Well Capitalized (in hundredths)	10.00%	10.00%
Total risk-based capital, Adequately Capitalized (in hundredths)	8.00%	8.00%
Leverage Capital [Abstract]
Tier One Risk Based Capital	349,580	335,759
Total risk-based capital	$ 376,565	$ 362,648
Leverage Ratios [Abstract]
Tier 1 risk-based capital, ratio (in hundredths)	16.35%	15.75%
Total risk-based capital, ratio (in hundredths)	17.62%	17.01%

The leverage ratio for most highly rated institutions considered to be adequately capitalized.

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Tier 1 capital as defined in the regulations.

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The Tier 1 Core capital ratio (core capital divided by assets) required to be categorized as "adequately capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 Core Capital divided by assets as defined in the regulations.

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Tier 1 Leverage Capital divided by ending assets as defined in the regulations.

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Tier 1 capital plus Tier 2 capital as defined in the regulations.

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The total risk based capital ratio (Tier 1 capital plus Tier 2 capital divided by risk weighted assets) required to be categorized as "adequately capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 capital plus Tier 2 capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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