Loans and Allowance for Loan Losses - Average balances of impaired loans and income recognized on impaired loans (Details 4) (Loans Receivable, USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	$ 104,283	$ 287,336	$ 179,309	$ 283,981
Interest Revenue Recognized During Impairment	1,195	2,421	3,021	4,688
Cash Basis Interest Revenue Received	1,194	3,216	3,712	6,408
Commercial (Secured By Real Estate)
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	52,191	125,419	74,233	112,633
Interest Revenue Recognized During Impairment	631	1,414	1,577	2,665
Cash Basis Interest Revenue Received	665	1,476	1,665	2,817
Commercial & industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	5,804	48,984	27,277	49,922
Interest Revenue Recognized During Impairment	63	191	219	309
Cash Basis Interest Revenue Received	70	700	699	1,310
Commercial construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	13,034	41,242	27,983	36,109
Interest Revenue Recognized During Impairment	114	217	265	484
Cash Basis Interest Revenue Received	115	304	347	761
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	71,029	215,645	129,493	198,664
Interest Revenue Recognized During Impairment	808	1,822	2,061	3,458
Cash Basis Interest Revenue Received	850	2,480	2,711	4,888
Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	18,950	19,645	20,179	25,060
Interest Revenue Recognized During Impairment	205	255	446	480
Cash Basis Interest Revenue Received	193	297	416	558
Residential construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	14,058	51,596	29,374	59,866
Interest Revenue Recognized During Impairment	178	336	504	737
Cash Basis Interest Revenue Received	147	431	575	949
Consumer installment
Financing Receivable, Allowance for Credit Losses [Line Items]
Average Balance	246	450	263	391
Interest Revenue Recognized During Impairment	4	8	10	13
Cash Basis Interest Revenue Received	$ 4	$ 8	$ 10	$ 13

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

+ References

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=28368275&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=28368275&loc=d3e5258-111524

+ Details

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

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- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

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