Loans (Summary of Information Related to Impaired Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	$ 116,869	$ 132,202	$ 122,100	$ 138,079
Interest income recognized related to loans with impaired status	858	720	2,732	2,491
Commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	27,025	28,683	26,894	27,684
Interest income recognized related to loans with impaired status	215	149	633	602
Real estate commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	50,266	54,524	53,482	59,063
Interest income recognized related to loans with impaired status	284	212	984	642
Real estate construction [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	414	912	395	470
Interest income recognized related to loans with impaired status	2	0	7	0
Land development [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	9,615	10,582	10,470	8,869
Interest income recognized related to loans with impaired status	79	71	261	216
Real estate residential [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	25,826	33,652	27,216	37,861
Interest income recognized related to loans with impaired status	278	288	847	1,031
Consumer installment [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	632	909	666	1,222
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	3,091	2,940	2,977	2,910
Interest income recognized related to loans with impaired status	$ 0	$ 0	$ 0	$ 0