Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Interest and dividend income:
Interest and fees on loans	$ 32,166	$ 32,103	$ 95,286	$ 96,805
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	4,411	4,915	13,249	14,540
Interest on held to maturity securities:
Total interest on held to maturity securities	840	1,361	2,871	4,770
Federal Reserve Bank and Federal Home Loan Bank stock	121	120	361	359
Interest on federal funds sold and other short-term investments	344	258	916	877
Total interest income	37,882	38,757	112,683	117,351
Interest expense:
Interest-bearing checking	84	79	246	235
Savings	798	870	2,543	2,951
Money market deposit accounts	590	673	1,905	2,366
Time deposits	1,937	2,629	5,640	9,277
Interest on short-term borrowings	370	348	1,101	1,114
Total interest expense	3,779	4,599	11,435	15,943
Net interest income	34,103	34,158	101,248	101,408
Provision for loan losses	1,500	2,900	5,500	9,000
Net interest income after provision for loan losses	32,603	31,258	95,748	92,408
Noninterest income:
Trustco financial services income	1,317	1,145	4,025	3,946
Fees for services to customers	2,903	3,234	8,758	8,904
Net gain on securities transactions	0	666	1,434	1,398
Other	194	172	705	555
Total noninterest income	4,414	5,217	14,922	14,803
Noninterest expenses:
Salaries and employee benefits	7,935	7,587	23,760	22,849
Net occupancy expense	3,911	3,756	11,874	11,368
Equipment expense	1,567	1,316	4,867	4,436
Professional services	1,255	1,657	4,240	4,582
Outsourced services	1,350	1,350	4,050	3,947
Advertising expense	548	935	1,992	2,804
FDIC and other insurance	1,009	983	3,023	2,816
Other real estate expense, net	946	1,210	3,168	2,841
Other	2,167	1,849	7,140	7,184
Total noninterest expenses	20,688	20,643	64,114	62,827
Income before taxes	16,329	15,832	46,556	44,384
Income taxes	6,077	6,079	17,373	16,656
Net income	10,252	9,753	29,183	27,728
Net income per Common Share:
Basic (in dollars per share)	$ 0.109	$ 0.104	$ 0.310	$ 0.296
Diluted (in dollars per share)	$ 0.109	$ 0.104	$ 0.310	$ 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	571	1,996	2,014	6,906
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	127	340	466	1,118
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	2,888	2,003	8,358	4,460
Interest on held to maturity securities:
Total interest on held to maturity securities	686	976	2,191	3,464
Corporate bonds [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	223	529	674	1,999
Interest on held to maturity securities:
Total interest on held to maturity securities	154	385	680	1,281
Small Business Administration-guaranteed participation securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	558	43	1,618	43
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	39	0	106	0
Other securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	$ 5	$ 4	$ 13	$ 14