Loans, Impaired Loans, Average Investments in Impaired Loans, and Interest Income Recognized on Impaired Loans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Total impaired loans [Abstract]
Recorded balance	$ 66,911		$ 63,292		$ 66,911		$ 63,292		$ 65,300
Unpaid Contractual Principal Balance	70,537		68,218		70,537		68,218		68,228
Specific Allowance	2,218		3,280		2,218		3,280		2,296
Average investment in impaired loans	68,862		63,739		67,440		64,574		64,890
Interest Income Recognized	570	[1]	624	[1]	1,702	[1]	1,613	[1]	2,083	[1]
Commercial Construction [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	5,250		5,586		5,250		5,586		5,457
Unpaid Contractual Principal Balance	5,251		6,163		5,251		6,163		5,458
Specific Allowance	0		0		0		0		0
Average Investment in Impaired Loans	5,259		5,597		5,330		5,622		5,595
Interest Income Recognized	44	[1]	77	[1]	172	[1]	204	[1]	240	[1]
Loans with a specific valuation allowance [Abstract]
Recorded Balance	4,149		4,557		4,149		4,557		4,353
Unpaid Contractual Principal Balance	4,149		4,563		4,149		4,563		4,359
Specific Allowance	734		1,827		734		1,827		1,189
Average Investment in Impaired Loans	4,213		4,572		4,270		5,101		4,935
Interest income recognized	0	[1]	0	[1]	0	[1]	0	[1]	0	[1]
Total impaired loans [Abstract]
Recorded balance	9,399		10,143		9,399		10,143		9,810
Unpaid Contractual Principal Balance	9,400		10,726		9,400		10,726		9,817
Specific Allowance	734		1,827		734		1,827		1,189
Average investment in impaired loans	9,472		10,169		9,600		10,723		10,530
Interest Income Recognized	44	[1]	77	[1]	172	[1]	204	[1]	240	[1]
Commercial Secured by Real Estate [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	33,010		31,054		33,010		31,054		35,258
Unpaid Contractual Principal Balance	34,086		31,929		34,086		31,929		36,173
Specific Allowance	0		0		0		0		0
Average Investment in Impaired Loans	33,290		31,142		34,464		31,491		32,472
Interest Income Recognized	261	[1]	405	[1]	858	[1]	938	[1]	1,231	[1]
Loans with a specific valuation allowance [Abstract]
Recorded Balance	6,070		5,423		6,070		5,423		4,039
Unpaid Contractual Principal Balance	6,219		5,733		6,219		5,733		4,326
Specific Allowance	1,273		1,295		1,273		1,295		1,005
Average Investment in Impaired Loans	6,076		5,622		4,912		5,362		5,033
Interest income recognized	5	[1]	0	[1]	9	[1]	0	[1]	1	[1]
Total impaired loans [Abstract]
Recorded balance	39,080		36,477		39,080		36,477		39,297
Unpaid Contractual Principal Balance	40,305		37,662		40,305		37,662		40,499
Specific Allowance	1,273		1,295		1,273		1,295		1,005
Average investment in impaired loans	39,366		36,764		39,376		36,853		37,505
Interest Income Recognized	266	[1]	405	[1]	867	[1]	938	[1]	1,232	[1]
Commercial Other [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	15,972		15,179		15,972		15,179		14,839
Unpaid Contractual Principal Balance	18,247		18,212		18,247		18,212		16,435
Specific Allowance	0		0		0		0		0
Average Investment in Impaired Loans	17,577		15,264		16,421		15,508		15,396
Interest Income Recognized	248	[1]	134	[1]	619	[1]	439	[1]	568	[1]
Loans with a specific valuation allowance [Abstract]
Recorded Balance	586		465		586		465		330
Unpaid Contractual Principal Balance	710		590		710		590		453
Specific Allowance	211		158		211		158		102
Average Investment in Impaired Loans	587		515		460		587		525
Interest income recognized	0	[1]	0	[1]	0	[1]	0	[1]	0	[1]
Total impaired loans [Abstract]
Recorded balance	16,558		15,644		16,558		15,644		15,169
Unpaid Contractual Principal Balance	18,957		18,802		18,957		18,802		16,888
Specific Allowance	211		158		211		158		102
Average investment in impaired loans	18,164		15,779		16,881		16,095		15,921
Interest Income Recognized	248	[1]	134	[1]	619	[1]	439	[1]	568	[1]
Real Estate Mortgage [Member]
Loans without a specific valuation allowance [Abstract]
Recorded Balance	1,874		1,028		1,874		1,028		1,024
Unpaid Contractual Principal Balance	1,875		1,028		1,875		1,028		1,024
Specific Allowance	0		0		0		0		0
Average Investment in Impaired Loans	1,860		1,027		1,583		903		934
Interest Income Recognized	12	[1]	8	[1]	44	[1]	32	[1]	43	[1]
Total impaired loans [Abstract]
Recorded balance	1,874		1,028		1,874		1,028		1,024
Unpaid Contractual Principal Balance	1,875		1,028		1,875		1,028		1,024
Specific Allowance	0		0		0		0		0
Average investment in impaired loans	1,860		1,027		1,583		903		934
Interest Income Recognized	$ 12	[1]	$ 8	[1]	$ 44	[1]	$ 32	[1]	$ 43	[1]

[1] Cash basis interest is substantially the same as interest income recognized.