Loans and Allowance for Loan Losses, Troubled Debt Restructurings (Details) (USD $)	3 Months Ended	9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013 Contract Loan	Sep. 30, 2013 Loan	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2013 Commercial and Industrial [Member] Contract	Sep. 30, 2012 Commercial and Industrial [Member] Contract	Sep. 30, 2013 Commercial and Industrial [Member] Contract	Sep. 30, 2012 Commercial and Industrial [Member] Contract	Sep. 30, 2013 Commercial Real Estate [Member] Contract	Sep. 30, 2012 Commercial Real Estate [Member] Contract	Sep. 30, 2013 Commercial Real Estate [Member] Contract	Sep. 30, 2012 Commercial Real Estate [Member] Contract	Sep. 30, 2013 Construction and Land [Member] Contract	Sep. 30, 2012 Construction and Land [Member] Contract	Sep. 30, 2013 Construction and Land [Member] Contract	Sep. 30, 2012 Construction and Land [Member] Contract	Sep. 30, 2013 Consumer [Member] Contract	Sep. 30, 2012 Consumer [Member] Contract	Sep. 30, 2013 Consumer [Member] Contract	Sep. 30, 2012 Consumer [Member] Contract	Sep. 30, 2013 Residential Real Estate [Member] Contract	Sep. 30, 2012 Residential Real Estate [Member] Contract	Sep. 30, 2013 Residential Real Estate [Member] Contract	Sep. 30, 2012 Residential Real Estate [Member] Contract	Sep. 30, 2013 Home Equity Line of Credit [Member] Contract	Sep. 30, 2012 Home Equity Line of Credit [Member] Contract	Sep. 30, 2013 Home Equity Line of Credit [Member] Contract	Sep. 30, 2012 Home Equity Line of Credit [Member] Contract	Sep. 30, 2013 Student US Government Guaranteed [Member] Contract	Sep. 30, 2012 Student US Government Guaranteed [Member] Contract	Sep. 30, 2013 Student US Government Guaranteed [Member] Contract	Sep. 30, 2012 Student US Government Guaranteed [Member] Contract
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings, number of contracts	3				2	1	2	2	0	1	2	2	1	1	2	4	0	0	0	0	0	0	1	0	0	0	0	0	0	0	0	0
Troubled debt restructurings, pre-modification outstanding recorded investment	$ 1,965,000				$ 292,000	$ 198,000	$ 292,000	$ 435,000	$ 0	$ 1,783,000	$ 2,010,000	$ 3,683,000	$ 1,673,000	$ 1,673,000	$ 2,481,000	$ 3,473,000	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 300,000	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Troubled debt restructurings, post-modification outstanding recorded investment					292,000	198,000	292,000	435,000	0	1,783,000	2,010,000	3,683,000	1,673,000	1,673,000	2,481,000	3,473,000	0	0	0	0	0	0	300,000	0	0	0	0	0	0	0	0	0
Troubled debt restructurings that subsequently defaulted, number of contracts					0	0	1	0	0	0	0	0	0	0	0	0	0		0	0	0		0	0	0		0	0	0		0	0
Troubled debt restructurings that subsequently defaulted, pre-modification outstanding recorded investment		0			0	0	237,000	0	0	0	0	0	0	0	0	0			0	0	0		0	0			0	0			0	0
Troubled debt restructurings that subsequently defaulted, post-modification outstanding recorded investment		0			0	0	237,000	0	0	0	0	0	0	0	0	0			0	0	0		0	0			0	0			0	0
Number of TDR loans secured by business assets	13	13
TDR loans value	9,530,000	9,530,000
Number of TDR loans current and performing	9	9
TDR loans current and performing	8,564,000	8,564,000
Number of TDR loans not performing in accordance with the modified terms	4	4
TDR loans not performing in accordance with modified terms	966,000	966,000
Non-performing Assets, Restructured Loans Still Accruing and Loans Contractually Past Due [Abstract]
Non-accrual loans	5,060,000	5,060,000	10,650,000	12,428,000
Other real estate owned	1,406,000	1,406,000	1,406,000	1,776,000
Non-performing corporate bond investments, at fair value	128,000	128,000	325,000	303,000
Total non-performing assets	6,594,000	6,594,000	12,381,000	14,507,000
Restructured loans still accruing	8,564,000	8,564,000	5,556,000	5,562,000
Student Loans 90 PD Still Accruing	3,629,000	3,629,000	0	0
Loans past due 90 or more days and still accruing	1,000	1,000	132,000	248,000
Total non-performing and other risk assets	$ 18,788,000	$ 18,788,000	$ 18,069,000	$ 20,317,000
Allowance for loan losses to total loans (in hundredths)	1.42%	1.42%	1.39%	1.90%
Non-accrual loans to total loans (in hundredths)	1.11%	1.11%	2.36%	2.74%
Allowance for loan losses to non-accrual loans (in hundredths)	128.08%	128.08%	58.76%	69.25%
Total non-accrual loans and restructured loans still accruing to total loans (in hundredths)	2.99%	2.99%	3.59%	3.96%
Allowance for loan losses to non-accrual loans and restructured loans still accruing (in hundredths)	47.57%	47.57%	38.62%	47.84%
Total non-performing assets to total assets (in hundredths)	1.11%	1.11%	2.06%	2.52%