Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Interest and dividend income:
Interest and fees on loans	$ 31,639	$ 32,277	$ 63,120	$ 64,702
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	4,314	4,991	8,838	9,625
Interest on held to maturity securities:
Total interest on held to maturity securities	930	1,585	2,031	3,409
Federal Reserve Bank and Federal Home Loan Bank stock	121	149	240	239
Interest on federal funds sold and other short-term investments	327	299	572	619
Total interest income	37,331	39,301	74,801	78,594
Interest expense:
Interest-bearing checking	82	78	162	156
Savings	829	979	1,745	2,081
Money market deposit accounts	630	770	1,315	1,693
Time deposits	1,883	3,230	3,703	6,648
Interest on short-term borrowings	367	378	731	766
Total interest expense	3,791	5,435	7,656	11,344
Net interest income	33,540	33,866	67,145	67,250
Provision for loan losses	2,000	3,000	4,000	6,100
Net interest income after provision for loan losses	31,540	30,866	63,145	61,150
Noninterest income:
Trustco financial services income	1,287	1,407	2,708	2,801
Fees for services to customers	2,968	2,939	5,855	5,670
Net gain on securities transactions	1,432	55	1,434	732
Other	229	176	511	383
Total noninterest income	5,916	4,577	10,508	9,586
Noninterest expenses:
Salaries and employee benefits	7,647	7,519	15,825	15,262
Net occupancy expense	3,910	3,817	7,963	7,612
Equipment expense	1,582	1,600	3,300	3,120
Professional services	1,565	1,489	2,985	2,925
Outsourced services	1,350	1,347	2,700	2,597
Advertising expense	714	1,060	1,444	1,869
FDIC and other insurance	1,004	953	2,014	1,833
Other real estate expense, net	1,473	665	2,222	1,631
Other	2,624	2,599	4,973	5,335
Total noninterest expenses	21,869	21,049	43,426	42,184
Income before taxes	15,587	14,394	30,227	28,552
Income taxes	5,824	5,328	11,296	10,577
Net income	9,763	9,066	18,931	17,975
Net income per Common Share:
Basic (in dollars per share)	$ 0.104	$ 0.097	$ 0.201	$ 0.192
Diluted (in dollars per share)	$ 0.104	$ 0.097	$ 0.201	$ 0.192
U. S. government sponsored enterprises [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	627	2,606	1,443	4,910
Interest on held to maturity securities:
Total interest on held to maturity securities	0	0	0	25
State and political subdivisions [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	148	368	339	778
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	2,701	1,364	5,470	2,457
Interest on held to maturity securities:
Total interest on held to maturity securities	716	1,198	1,505	2,488
Corporate bonds [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	233	648	451	1,470
Interest on held to maturity securities:
Total interest on held to maturity securities	214	387	526	896
Small Business Administration-guaranteed participation securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	564	0	1,060	0
Mortgage-backed securities and collateralized mortgage obligations-Commercial [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	38	0	67	0
Other securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	$ 3	$ 5	$ 8	$ 10