Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest and dividend income:
Interest and fees on loans	$ 32,103	$ 32,640	$ 96,805	$ 96,501
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	4,915	5,640	14,540	17,513
Interest on held to maturity securities:
Total interest on held to maturity securities	1,361	1,915	4,770	5,653
Federal Reserve Bank and Federal Home Loan Bank stock	120	84	359	225
Interest on federal funds sold and other short-term investments	258	318	877	818
Total interest income	38,757	40,597	117,351	120,710
Interest on deposits:
Interest-bearing checking	79	74	235	209
Savings	870	952	2,951	2,770
Money market deposit accounts	673	1,158	2,366	3,569
Time deposits	2,629	3,904	9,277	12,446
Interest on short-term borrowings	348	384	1,114	1,173
Total interest expense	4,599	6,472	15,943	20,167
Net interest income	34,158	34,125	101,408	100,543
Provision for loan losses	2,900	5,100	9,000	14,550
Net interest income after provision for loan losses	31,258	29,025	92,408	85,993
Noninterest income:
Trustco financial services income	1,145	1,242	3,946	4,002
Fees for services to customers	2,610	2,189	7,238	6,608
Net gain on securities transactions	666	158	1,398	1,296
Other	172	214	555	739
Total noninterest income	4,593	3,803	13,137	12,645
Noninterest expenses:
Salaries and employee benefits	7,587	7,087	22,849	21,113
Net occupancy expense	3,756	3,614	11,368	11,023
Equipment expense	1,316	1,639	4,436	4,452
Professional services	1,657	1,152	4,582	4,318
Outsourced services	1,350	1,350	3,947	4,050
Advertising expense	935	763	2,804	2,177
FDIC and other insurance	983	835	2,816	4,078
Other real estate expense, net	1,210	754	2,841	4,439
Other	1,225	1,249	5,518	5,191
Total noninterest expenses	20,019	18,443	61,161	60,841
Income before taxes	15,832	14,385	44,384	37,797
Income taxes	6,079	5,160	16,656	13,424
Net income	9,753	9,225	27,728	24,373
Net income per Common Share:
Basic (in dollars per share)	$ 0.104	$ 0.100	$ 0.296	$ 0.296
Diluted (in dollars per share)	$ 0.104	$ 0.100	$ 0.296	$ 0.296
U. S. government sponsored enterprises [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	1,996	3,347	6,906	10,337
Interest on held to maturity securities:
Total interest on held to maturity securities	0	164	25	164
State and political subdivisions [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	340	557	1,118	1,981
Mortgage-backed securities and collateralized mortgage obligations-residential [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	2,003	778	4,460	2,008
Interest on held to maturity securities:
Total interest on held to maturity securities	976	1,186	3,464	3,614
Corporate bonds [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	529	953	1,999	3,173
Interest on held to maturity securities:
Total interest on held to maturity securities	385	565	1,281	1,875
Small Business Administration-guaranteed participation securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	43	0	43	0
Other securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	$ 4	$ 5	$ 14	$ 14