Loans (Summary of Information Related to Impaired Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	$ 131,534	$ 129,459
Interest income recognized related to loans with impaired status	1,180	1,034
Commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	38,576	41,607
Interest income recognized related to loans with impaired status	289	333
Real estate commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	60,240	53,320
Interest income recognized related to loans with impaired status	525	361
Real estate construction [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	640	167
Interest income recognized related to loans with impaired status	0	0
Land development [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	1,875	4,643
Interest income recognized related to loans with impaired status	27	37
Real estate residential [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	27,352	26,781
Interest income recognized related to loans with impaired status	331	303
Consumer installment [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	499	773
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	2,352	2,168
Interest income recognized related to loans with impaired status	$ 8	$ 0