Loans, Nonaccrual Loans Segregated by Class of Loans and Loan Portfolio Aging Analysis, Segregated by Class (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Nonaccrual loans and loan portfolio aging analysis, segregated by class [Line Items]
Nonaccrual loans segregated by class of loans	$ 18,337		$ 16,791
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	14,858		19,471
60-89 Days Past Due	12,103		9,033
90+ Days Past Due	31,348		33,911
Total Past Due	58,309		62,415
Current	2,505,005		2,488,158
Total Loans	2,563,314		2,550,573
90+ and Accruing	15,533	[1]	19,215	[1]
Commercial Construction [Member]
Nonaccrual loans and loan portfolio aging analysis, segregated by class [Line Items]
Nonaccrual loans segregated by class of loans	6,196		5,955
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	617		1,413
60-89 Days Past Due	16		312
90+ Days Past Due	8,599		9,598
Total Past Due	9,232		11,323
Current	93,071		108,124
Total Loans	102,303		119,447
90+ and Accruing	2,532	[1]	3,778	[1]
Commercial Secured by Real Estate [Member]
Nonaccrual loans and loan portfolio aging analysis, segregated by class [Line Items]
Nonaccrual loans segregated by class of loans	6,256		5,572
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	6,619		9,733
60-89 Days Past Due	7,111		1,633
90+ Days Past Due	9,129		10,456
Total Past Due	22,859		21,822
Current	824,948		785,391
Total Loans	847,807		807,213
90+ and Accruing	4,475	[1]	5,943	[1]
Commercial Other [Member]
Nonaccrual loans and loan portfolio aging analysis, segregated by class [Line Items]
Nonaccrual loans segregated by class of loans	1,344		1,655
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	1,776		259
60-89 Days Past Due	1,398		1,142
90+ Days Past Due	5,101		5,164
Total Past Due	8,275		6,565
Current	367,134		369,783
Total Loans	375,409		376,348
90+ and Accruing	3,827	[1]	3,867	[1]
Equipment Lease Financing [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	0		0
60-89 Days Past Due	0		0
90+ Days Past Due	0		0
Total Past Due	0		0
Current	9,944		9,246
Total Loans	9,944		9,246
90+ and Accruing	0	[1]	0	[1]
Real Estate Construction [Member]
Nonaccrual loans and loan portfolio aging analysis, segregated by class [Line Items]
Nonaccrual loans segregated by class of loans	635		315
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	195		248
60-89 Days Past Due	272		572
90+ Days Past Due	866		511
Total Past Due	1,333		1,331
Current	50,645		53,710
Total Loans	51,978		55,041
90+ and Accruing	232	[1]	196	[1]
Real Estate Mortgage [Member]
Nonaccrual loans and loan portfolio aging analysis, segregated by class [Line Items]
Nonaccrual loans segregated by class of loans	3,763		3,153
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	1,822		2,765
60-89 Days Past Due	2,394		4,029
90+ Days Past Due	6,698		7,138
Total Past Due	10,914		13,932
Current	685,407		682,996
Total Loans	696,321		696,928
90+ and Accruing	3,635	[1]	4,511	[1]
Home Equity [Member]
Nonaccrual loans and loan portfolio aging analysis, segregated by class [Line Items]
Nonaccrual loans segregated by class of loans	143		141
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	1,118		921
60-89 Days Past Due	119		102
90+ Days Past Due	497		565
Total Past Due	1,734		1,588
Current	78,165		80,704
Total Loans	79,899		82,292
90+ and Accruing	374	[1]	441	[1]
Consumer Direct [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	851		1,360
60-89 Days Past Due	247		336
90+ Days Past Due	79		98
Total Past Due	1,177		1,794
Current	118,014		120,787
Total Loans	119,191		122,581
90+ and Accruing	79	[1]	98	[1]
Consumer Indirect [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
30-59 Days Past Due	1,860		2,772
60-89 Days Past Due	546		907
90+ Days Past Due	379		381
Total Past Due	2,785		4,060
Current	277,677		277,417
Total Loans	280,462		281,477
90+ and Accruing	$ 379	[1]	$ 381	[1]

[1] 90+ and Accruing are also included in 90+ Days Past Due column.