Loans (Summary of Information Related to Impaired Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	$ 121,855	$ 136,942	$ 124,715	$ 137,418
Interest income recognized related to loans with impaired status	1,005	904	1,874	1,771
Commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	26,704	29,018	26,828	27,183
Interest income recognized related to loans with impaired status	225	279	418	453
Real estate commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	53,434	59,903	55,090	61,333
Interest income recognized related to loans with impaired status	412	202	700	430
Real estate construction [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	410	435	386	249
Interest income recognized related to loans with impaired status	3	0	5	0
Land development [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	10,879	8,301	10,897	8,014
Interest income recognized related to loans with impaired status	91	73	182	145
Real estate residential [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	26,903	35,100	27,911	36,365
Interest income recognized related to loans with impaired status	274	350	569	743
Consumer installment [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	647	1,219	683	1,379
Interest income recognized related to loans with impaired status	0	0	0	0
Home equity [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	2,878	2,966	2,920	2,895
Interest income recognized related to loans with impaired status	$ 0	$ 0	$ 0	$ 0