Loans (Summary of Information Related to Impaired Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	$ 127,576	$ 137,893
Interest income recognized related to loans with impaired status	869	867
Commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	26,953	26,096
Interest income recognized related to loans with impaired status	193	174
Real estate commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	56,745	62,015
Interest income recognized related to loans with impaired status	288	228
Real estate construction [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	363	64
Interest income recognized related to loans with impaired status	2	0
Land development [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	10,914	7,727
Interest income recognized related to loans with impaired status	91	72
Real estate residential [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	28,920	37,629
Interest income recognized related to loans with impaired status	295	393
Consumer installment [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	719	1,538
Interest income recognized related to loans with impaired status	0	0
Home equity [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	2,962	2,824
Interest income recognized related to loans with impaired status	$ 0	$ 0