Loans and Allowance for Loan Losses (Evaluation for Impairment) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
ALL, individually evaluated for impairment	$ 486		$ 1,737
ALL, collectively evaluated for impairment	20,835		22,204
ALL, PI loans evluated for credit impairment	4,066		5,373
ALL, PI loans with no credit deterioration	0		0
Total ALL evaluated for impairment	25,387	25,085	29,314		30,859	38,551	39,360
Loans held for investment, individually evaluated for impairment	52,320		77,594
Loans held for investment, collectively evaluated for impairment	966,229		871,049
Loans held for investment, PI loans with subsequent credit deterioration	147,852		192,115
Loans held for investment, PI loans with no credit deterioration	28,741		36,277
Loans held for investment	1,195,142		1,177,035	[1]
Commercial and agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
ALL, individually evaluated for impairment	0		282
ALL, collectively evaluated for impairment	2,576		2,432
ALL, PI loans evluated for credit impairment	34		524
ALL, PI loans with no credit deterioration	0		0
Total ALL evaluated for impairment	2,610	2,192	3,238		5,153	7,151	5,776
Loans held for investment, individually evaluated for impairment	416		2,334
Loans held for investment, collectively evaluated for impairment	57,783		62,704
Loans held for investment, PI loans with subsequent credit deterioration	8,821		11,533
Loans held for investment, PI loans with no credit deterioration	2,597		3,133
Loans held for investment	69,617		79,704
Real estate - construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
ALL, individually evaluated for impairment	1		82
ALL, collectively evaluated for impairment	4,347		4,705
ALL, PI loans evluated for credit impairment	747		200
ALL, PI loans with no credit deterioration	0		0
Total ALL evaluated for impairment	5,095	5,652	4,987		5,983	11,320	11,995
Loans held for investment, individually evaluated for impairment	9,998		13,533
Loans held for investment, collectively evaluated for impairment	47,348		42,199
Loans held for investment, PI loans with subsequent credit deterioration	8,258		2,285
Loans held for investment, PI loans with no credit deterioration	1,938		397
Loans held for investment	67,542		58,414
Real estate - mortgage, 1-4 family residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
ALL, individually evaluated for impairment	446		607
ALL, collectively evaluated for impairment	7,811		7,383
ALL, PI loans evluated for credit impairment	527		711
ALL, PI loans with no credit deterioration	0		0
Total ALL evaluated for impairment	8,784	7,400	8,701		9,994	8,784	8,885
Loans held for investment, individually evaluated for impairment	13,060		18,118
Loans held for investment, collectively evaluated for impairment	575,490		496,205
Loans held for investment, PI loans with subsequent credit deterioration	26,661		34,961
Loans held for investment, PI loans with no credit deterioration	3,051		4,254
Loans held for investment	618,262		553,538
Real estate - mortgage, commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
ALL, individually evaluated for impairment	39		766
ALL, collectively evaluated for impairment	3,869		5,473
ALL, PI loans evluated for credit impairment	2,567		3,388
ALL, PI loans with no credit deterioration	0		0
Total ALL evaluated for impairment	6,475	7,387	9,627		7,058	9,218	11,063
Loans held for investment, individually evaluated for impairment	28,846		43,609
Loans held for investment, collectively evaluated for impairment	242,062		227,760
Loans held for investment, PI loans with subsequent credit deterioration	103,028		141,974
Loans held for investment, PI loans with no credit deterioration	21,150		28,493
Loans held for investment	395,086		441,836
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
ALL, individually evaluated for impairment	0		0
ALL, collectively evaluated for impairment	2,232		2,211
ALL, PI loans evluated for credit impairment	191		550
ALL, PI loans with no credit deterioration	0		0
Total ALL evaluated for impairment	2,423	2,454	2,761		2,671	2,078	1,641
Loans held for investment, individually evaluated for impairment	0		0
Loans held for investment, collectively evaluated for impairment	43,546		42,181
Loans held for investment, PI loans with subsequent credit deterioration	1,084		1,362
Loans held for investment, PI loans with no credit deterioration	5		0
Loans held for investment	$ 44,635		$ 43,543

[1] Derived from audited consolidated financial statements