Impaired Loans and Valuation Allowance for Loan Losses (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Company's recorded investments in impaired loans and the related valuation allowances
Recorded Investment, Total	$ 62,878	$ 82,901
Unpaid Principal Balance, Total	74,116	93,023
Related Valuation Allowance, Total	5,359	7,269
Construction and land development [Member]
Company's recorded investments in impaired loans and the related valuation allowances
With No Related Allowance, Recorded Investment	2,736	1,128
With No Related Allowance, Unpaid Principal Balance	3,419	1,608
With No Related Allowance, Related Valuation Allowance	0	0
With Related Allowance, Recorded Investment	1,112	2,897
With Related Allowance, Unpaid Principal Balance	1,188	2,941
With Related Allowance, Related Valuation Allowance	175	230
Recorded Investment, Total	3,848	4,025
Unpaid Principal Balance, Total	4,607	4,549
Related Valuation Allowance, Total	175	230
Commercial real estate [Member]
Company's recorded investments in impaired loans and the related valuation allowances
With No Related Allowance, Recorded Investment	7,335	12,357
With No Related Allowance, Unpaid Principal Balance	10,170	14,337
With No Related Allowance, Related Valuation Allowance	0	0
With Related Allowance, Recorded Investment	13,821	26,130
With Related Allowance, Unpaid Principal Balance	14,348	26,648
With Related Allowance, Related Valuation Allowance	1,054	2,264
Recorded Investment, Total	21,156	38,487
Unpaid Principal Balance, Total	24,518	40,985
Related Valuation Allowance, Total	1,054	2,264
Residential real estate [Member]
Company's recorded investments in impaired loans and the related valuation allowances
With No Related Allowance, Recorded Investment	14,315	15,463
With No Related Allowance, Unpaid Principal Balance	20,783	22,022
With No Related Allowance, Related Valuation Allowance	0	0
With Related Allowance, Recorded Investment	22,847	24,256
With Related Allowance, Unpaid Principal Balance	23,441	24,752
With Related Allowance, Related Valuation Allowance	4,006	4,700
Recorded Investment, Total	37,162	39,719
Unpaid Principal Balance, Total	44,224	46,774
Related Valuation Allowance, Total	4,006	4,700
Commercial and financial [Member]
Company's recorded investments in impaired loans and the related valuation allowances
With No Related Allowance, Recorded Investment	0	0
With No Related Allowance, Unpaid Principal Balance	0	0
With No Related Allowance, Related Valuation Allowance	0	0
With Related Allowance, Recorded Investment	0	0
With Related Allowance, Unpaid Principal Balance	0	0
With Related Allowance, Related Valuation Allowance	0	0
Recorded Investment, Total	0	0
Unpaid Principal Balance, Total	0	0
Related Valuation Allowance, Total	0	0
Consumer [Member]
Company's recorded investments in impaired loans and the related valuation allowances
With No Related Allowance, Recorded Investment	141	223
With No Related Allowance, Unpaid Principal Balance	178	255
With No Related Allowance, Related Valuation Allowance	0	0
With Related Allowance, Recorded Investment	571	447
With Related Allowance, Unpaid Principal Balance	589	460
With Related Allowance, Related Valuation Allowance	124	75
Recorded Investment, Total	712	670
Unpaid Principal Balance, Total	767	715
Related Valuation Allowance, Total	$ 124	$ 75