Loans and Allowance for Loan Losses (Details 4) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	$ 19,007,000	$ 20,038,000
Recorded Principal Balance, with no related allowance	10,931,000	11,752,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	11,342,000	16,770,000
Impaired loans, Unpaid Contractual Principal Balance	61,115,000	69,166,000
Impaired loans, Recorded Principal Balance	51,700,000	57,279,000
Impaired loans, Related Allowance	14,893,000	17,189,000
Impaired loans, Year-To-Date Average Recorded Principal Balance	54,489,000	61,318,000
Unpaid Contractual Principal Balance, with related allowance	42,108,000	49,128,000
Recorded Principal Balance, with related allowance	40,769,000	45,527,000
Year-To-Date Average Recorded Principal Balance, with related allowance	43,147,000	44,548,000
Commercial and industrial [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	2,972,000	1,926,000
Recorded Principal Balance, with no related allowance	1,556,000	1,617,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	1,587,000	3,140,000
Impaired loans, Related Allowance	1,407,000	924,000
Unpaid Contractual Principal Balance, with related allowance	2,616,000	3,221,000
Recorded Principal Balance, with related allowance	2,506,000	1,926,000
Year-To-Date Average Recorded Principal Balance, with related allowance	2,216,000	3,110,000
Vacant land, land development, and residential construction [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	2,342,000	2,356,000
Recorded Principal Balance, with no related allowance	1,378,000	1,401,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	1,389,000	1,848,000
Impaired loans, Related Allowance	726,000	1,367,000
Unpaid Contractual Principal Balance, with related allowance	1,958,000	2,333,000
Recorded Principal Balance, with related allowance	1,480,000	2,219,000
Year-To-Date Average Recorded Principal Balance, with related allowance	1,849,000	3,267,000
Real estate - owner occupied [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	2,314,000	2,368,000
Recorded Principal Balance, with no related allowance	1,349,000	1,557,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	1,453,000	3,139,000
Impaired loans, Related Allowance	1,162,000	1,388,000
Unpaid Contractual Principal Balance, with related allowance	3,417,000	4,307,000
Recorded Principal Balance, with related allowance	2,953,000	3,626,000
Year-To-Date Average Recorded Principal Balance, with related allowance	3,289,000	4,913,000
Real estate - non-owner occupied [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	7,440,000	9,984,000
Recorded Principal Balance, with no related allowance	4,717,000	5,492,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	5,105,000	6,578,000
Impaired loans, Related Allowance	10,411,000	11,773,000
Unpaid Contractual Principal Balance, with related allowance	30,428,000	33,818,000
Recorded Principal Balance, with related allowance	30,322,000	32,964,000
Year-To-Date Average Recorded Principal Balance, with related allowance	31,643,000	25,061,000
Real estate - multi-family and residential rental [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	1,729,000	1,188,000
Recorded Principal Balance, with no related allowance	684,000	413,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	549,000	756,000
Impaired loans, Related Allowance	910,000	1,408,000
Unpaid Contractual Principal Balance, with related allowance	2,761,000	4,471,000
Recorded Principal Balance, with related allowance	2,691,000	3,923,000
Year-To-Date Average Recorded Principal Balance, with related allowance	3,307,000	7,429,000
Total commercial [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	16,797,000	17,822,000
Recorded Principal Balance, with no related allowance	9,684,000	10,480,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	10,083,000	15,461,000
Impaired loans, Unpaid Contractual Principal Balance	57,977,000	65,972,000
Impaired loans, Recorded Principal Balance	49,636,000	55,138,000
Impaired loans, Related Allowance	14,616,000	16,860,000
Impaired loans, Year-To-Date Average Recorded Principal Balance	52,387,000	59,241,000
Unpaid Contractual Principal Balance, with related allowance	41,180,000	48,150,000
Recorded Principal Balance, with related allowance	39,952,000	44,658,000
Year-To-Date Average Recorded Principal Balance, with related allowance	42,304,000	43,780,000
Retail home equity and other [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	580,000	580,000
Recorded Principal Balance, with no related allowance	480,000	483,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	481,000	579,000
Impaired loans, Related Allowance	155,000	204,000
Unpaid Contractual Principal Balance, with related allowance	369,000	423,000
Recorded Principal Balance, with related allowance	346,000	394,000
Year-To-Date Average Recorded Principal Balance, with related allowance	370,000	286,000
Retail 1-4 family mortgages [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	1,630,000	1,636,000
Recorded Principal Balance, with no related allowance	767,000	789,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	778,000	730,000
Impaired loans, Related Allowance	122,000	125,000
Unpaid Contractual Principal Balance, with related allowance	559,000	555,000
Recorded Principal Balance, with related allowance	471,000	475,000
Year-To-Date Average Recorded Principal Balance, with related allowance	473,000	482,000
Total retail [Member]
Impaired loans
Unpaid Contractual Principal Balance, with no related allowance	2,210,000	2,216,000
Recorded Principal Balance, with no related allowance	1,247,000	1,272,000
Year-To-Date Average Recorded Principal Balance, with no related allowance	1,259,000	1,309,000
Impaired loans, Unpaid Contractual Principal Balance	3,138,000	3,194,000
Impaired loans, Recorded Principal Balance	2,064,000	2,141,000
Impaired loans, Related Allowance	277,000	329,000
Impaired loans, Year-To-Date Average Recorded Principal Balance	2,102,000	2,077,000
Unpaid Contractual Principal Balance, with related allowance	928,000	978,000
Recorded Principal Balance, with related allowance	817,000	869,000
Year-To-Date Average Recorded Principal Balance, with related allowance	$ 843,000	$ 768,000

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5258-111524

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

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