Loans and Allowance for Loan Losses (Impairment Allowances) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Construction and Land Development Loans
Financing Receivable, Impaired [Line Items]
Loans without a specific valuation allowance, Recorded Balance	$ 6,915	$ 11,279	$ 6,915	$ 11,279	$ 9,539
Loans without a specific valuation allowance, Unpaid Principal Balance	9,269	14,152	9,269	14,152	13,915
Loans with a specific valuation allowance, Recorded Balance	4,208	12,936	4,208	12,936	8,620
Loans with a specific valuation allowance, Unpaid Principal Balance	4,208	16,630	4,208	16,630	11,294
Total, Recorded Balance	11,123	24,215	11,123	24,215	18,159
Total, Unpaid Principal Balance	13,477	30,782	13,477	30,782	25,209
Specific Allowance	1,165	2,350	1,165	2,350	1,750
Loans without a specific valuation allowance, Average Investment in Impaired Loans	6,935	9,131	10,861	12,952
Loans without a specific valuation allowance, Interest Income Recognized	80	147	308	394
Loans with a specific valuation allowance, Average Investment In Impaired Loans	2,978	10,497	3,981	13,283
Loans with a specific valuation allowance, Interest Income Recognized	38	106	139	299
Total, Average Investment In Impaired Loans	9,913	19,628	14,842	26,235
Total, Interest Income Recognized	118	253	447	693
Other Commercial Real Estate Loans
Financing Receivable, Impaired [Line Items]
Loans without a specific valuation allowance, Recorded Balance	29,160	33,835	29,160	33,835	33,048
Loans without a specific valuation allowance, Unpaid Principal Balance	29,299	36,452	29,299	36,452	36,117
Loans with a specific valuation allowance, Recorded Balance	15,145	12,083	15,145	12,083	7,722
Loans with a specific valuation allowance, Unpaid Principal Balance	16,555	13,753	16,555	13,753	8,471
Total, Recorded Balance	44,305	45,918	44,305	45,918	40,770
Total, Unpaid Principal Balance	45,854	50,205	45,854	50,205	44,588
Specific Allowance	2,182	1,381	2,182	1,381	894
Loans without a specific valuation allowance, Average Investment in Impaired Loans	24,168	34,221	31,291	34,193
Loans without a specific valuation allowance, Interest Income Recognized	266	384	1,110	1,158
Loans with a specific valuation allowance, Average Investment In Impaired Loans	24,748	3,450	15,236	12,205
Loans with a specific valuation allowance, Interest Income Recognized	297	67	526	114
Total, Average Investment In Impaired Loans	48,916	37,671	46,527	46,398
Total, Interest Income Recognized	563	451	1,636	1,272
Asset-based Loans
Financing Receivable, Impaired [Line Items]
Loans without a specific valuation allowance, Recorded Balance	0	0	0	0	0
Loans without a specific valuation allowance, Unpaid Principal Balance	0	0	0	0	0
Loans with a specific valuation allowance, Recorded Balance	0	0	0	0	0
Loans with a specific valuation allowance, Unpaid Principal Balance	0	0	0	0	0
Total, Recorded Balance	0	0	0	0	0
Total, Unpaid Principal Balance	0	0	0	0	0
Specific Allowance	0	0	0	0	0
Loans without a specific valuation allowance, Average Investment in Impaired Loans	0	0	0	0
Loans without a specific valuation allowance, Interest Income Recognized	0	0	0	0
Loans with a specific valuation allowance, Average Investment In Impaired Loans	0	0	0	0
Loans with a specific valuation allowance, Interest Income Recognized	0	0	0	0
Total, Average Investment In Impaired Loans	0	0	0	0
Total, Interest Income Recognized	0	0	0	0
Other Commercial Loans
Financing Receivable, Impaired [Line Items]
Loans without a specific valuation allowance, Recorded Balance	967	526	967	526	433
Loans without a specific valuation allowance, Unpaid Principal Balance	967	553	967	553	460
Loans with a specific valuation allowance, Recorded Balance	481	1,373	481	1,373	1,111
Loans with a specific valuation allowance, Unpaid Principal Balance	578	1,475	578	1,475	1,111
Total, Recorded Balance	1,448	1,899	1,448	1,899	1,544
Total, Unpaid Principal Balance	1,545	2,028	1,545	2,028	1,571
Specific Allowance	450	614	450	614	485
Loans without a specific valuation allowance, Average Investment in Impaired Loans	1,549	1,486	965	2,567
Loans without a specific valuation allowance, Interest Income Recognized	17	4	39	83
Loans with a specific valuation allowance, Average Investment In Impaired Loans	42	1,214	477	2,672
Loans with a specific valuation allowance, Interest Income Recognized	5	29	12	91
Total, Average Investment In Impaired Loans	1,591	2,700	1,442	5,239
Total, Interest Income Recognized	22	33	51	174
Home Equity Loans
Financing Receivable, Impaired [Line Items]
Loans without a specific valuation allowance, Recorded Balance	1,080	384	1,080	384	159
Loans without a specific valuation allowance, Unpaid Principal Balance	1,080	384	1,080	384	159
Loans with a specific valuation allowance, Recorded Balance	74	207	74	207	456
Loans with a specific valuation allowance, Unpaid Principal Balance	74	207	74	207	456
Total, Recorded Balance	1,154	591	1,154	591	615
Total, Unpaid Principal Balance	1,154	591	1,154	591	615
Specific Allowance	36	116	36	116	166
Loans without a specific valuation allowance, Average Investment in Impaired Loans	1,831	0	1,102	389
Loans without a specific valuation allowance, Interest Income Recognized	15	0	29	4
Loans with a specific valuation allowance, Average Investment In Impaired Loans	76	614	159	207
Loans with a specific valuation allowance, Interest Income Recognized	1	1	7	1
Total, Average Investment In Impaired Loans	1,907	614	1,261	596
Total, Interest Income Recognized	16	1	36	5
Other 1-4 Family Residential Loans
Financing Receivable, Impaired [Line Items]
Loans without a specific valuation allowance, Recorded Balance	5,092	4,694	5,092	4,694	4,466
Loans without a specific valuation allowance, Unpaid Principal Balance	5,191	4,939	5,191	4,939	4,732
Loans with a specific valuation allowance, Recorded Balance	1,556	1,749	1,556	1,749	1,843
Loans with a specific valuation allowance, Unpaid Principal Balance	1,556	1,771	1,556	1,771	1,843
Total, Recorded Balance	6,648	6,443	6,648	6,443	6,309
Total, Unpaid Principal Balance	6,747	6,710	6,747	6,710	6,575
Specific Allowance	400	569	400	569	397
Loans without a specific valuation allowance, Average Investment in Impaired Loans	7,702	7,927	5,723	4,747
Loans without a specific valuation allowance, Interest Income Recognized	75	119	193	184
Loans with a specific valuation allowance, Average Investment In Impaired Loans	832	0	1,917	1,754
Loans with a specific valuation allowance, Interest Income Recognized	4	0	53	44
Total, Average Investment In Impaired Loans	8,534	7,927	7,640	6,501
Total, Interest Income Recognized	79	119	246	228
Consumer Loans
Financing Receivable, Impaired [Line Items]
Loans without a specific valuation allowance, Recorded Balance	100	120	100	120	128
Loans without a specific valuation allowance, Unpaid Principal Balance	104	146	104	146	154
Loans with a specific valuation allowance, Recorded Balance	39	26	39	26	37
Loans with a specific valuation allowance, Unpaid Principal Balance	39	26	39	26	37
Total, Recorded Balance	139	146	139	146	165
Total, Unpaid Principal Balance	143	172	143	172	191
Specific Allowance	39	26	39	26	37
Loans without a specific valuation allowance, Average Investment in Impaired Loans	272	0	171	166
Loans without a specific valuation allowance, Interest Income Recognized	4	0	9	14
Loans with a specific valuation allowance, Average Investment In Impaired Loans	39	0	71	30
Loans with a specific valuation allowance, Interest Income Recognized	0	0	3	1
Total, Average Investment In Impaired Loans	311	0	242	196
Total, Interest Income Recognized	$ 4	$ 0	$ 12	$ 15