Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Interest and dividend income:
Interest and fees on loans	$ 33,614	$ 31,639	$ 66,488	$ 63,120
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	4,307	4,314	8,616	8,838
Interest on held to maturity securities:
Total interest on held to maturity securities	731	930	1,510	2,031
Federal Reserve Bank and Federal Home Loan Bank stock	128	121	261	240
Interest on federal funds sold and other short-term investments	376	327	727	572
Total interest income	39,156	37,331	77,602	74,801
Interest expense:
Interest-bearing checking	89	82	173	162
Savings	592	829	1,355	1,745
Money market deposit accounts	618	630	1,217	1,315
Time deposits	2,035	1,883	3,986	3,703
Interest on short-term borrowings	342	367	735	731
Total interest expense	3,676	3,791	7,466	7,656
Net interest income	35,480	33,540	70,136	67,145
Provision for loan losses	1,500	2,000	3,000	4,000
Net interest income after provision for loan losses	33,980	31,540	67,136	63,145
Noninterest income:
Trustco financial services income	1,405	1,287	2,915	2,708
Fees for services to customers	2,732	2,968	5,253	5,855
Net gain on securities transactions	0	1,432	6	1,434
Other	368	229	2,090	511
Total noninterest income	4,505	5,916	10,264	10,508
Noninterest expenses:
Salaries and employee benefits	8,012	7,647	15,604	15,825
Net occupancy expense	4,110	3,910	8,369	7,963
Equipment expense	1,823	1,582	3,575	3,300
Professional services	1,438	1,565	2,724	2,985
Outsourced services	1,425	1,350	2,750	2,700
Advertising expense	657	714	1,256	1,444
FDIC and other insurance	1,000	1,004	1,904	2,014
Other real estate (income) expense, net	(1,688)	1,473	(833)	2,222
Other	2,660	2,624	4,889	4,973
Total noninterest expenses	19,437	21,869	40,238	43,426
Income before taxes	19,048	15,587	37,162	30,227
Income taxes	7,240	5,824	14,343	11,296
Net income	11,808	9,763	22,819	18,931
Net income per Common Share:
Basic (in dollars per share)	$ 0.125	$ 0.104	$ 0.241	$ 0.201
Diluted (in dollars per share)	$ 0.125	$ 0.104	$ 0.241	$ 0.201
U. S. government sponsored enterprises [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	381	627	887	1,443
State and political subdivisions [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	44	148	112	339
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	3,299	2,701	6,377	5,470
Interest on held to maturity securities:
Total interest on held to maturity securities	577	716	1,202	1,505
Corporate bonds [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	2	233	61	451
Interest on held to maturity securities:
Total interest on held to maturity securities	154	214	308	526
Small Business Administration-guaranteed participation securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	539	564	1,095	1,060
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	38	76	67
Other securities [Member]
Interest and dividends on securities available for sale:
Total interest and dividends on securities available for sale	$ 4	$ 3	$ 8	$ 8