Loans (Summary of Information Related to Impaired Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	$ 124,375	$ 116,869	$ 127,263	$ 122,100
Interest income recognized related to loans with impaired status	949	858	3,058	2,732
Commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	41,903	27,025	42,046	26,894
Interest income recognized related to loans with impaired status	346	215	1,026	633
Real estate commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	50,133	50,266	51,571	53,482
Interest income recognized related to loans with impaired status	263	284	990	984
Real estate construction [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	162	414	164	395
Interest income recognized related to loans with impaired status	0	2	0	7
Land development [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	3,284	9,615	4,079	10,470
Interest income recognized related to loans with impaired status	30	79	101	261
Real estate residential [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	26,166	25,826	26,561	27,216
Interest income recognized related to loans with impaired status	310	278	941	847
Consumer installment [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	481	632	630	666
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	2,246	3,091	2,212	2,977
Interest income recognized related to loans with impaired status	$ 0	$ 0	$ 0	$ 0