Loans (Summary of Information Related to Impaired Loans) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	$ 125,133	$ 131,805	$ 130,952	$ 131,670
Interest income recognized related to loans with impaired status	1,135	1,152	2,329	2,332
Commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	38,606	36,735	41,811	37,655
Interest income recognized related to loans with impaired status	348	263	677	552
Real estate commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	53,723	60,393	55,839	60,317
Interest income recognized related to loans with impaired status	391	458	849	983
Real estate construction [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	2,265	2,290	2,166	2,403
Interest income recognized related to loans with impaired status	26	36	51	63
Real estate residential [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	27,418	29,432	27,755	28,392
Interest income recognized related to loans with impaired status	356	380	722	711
Consumer installment [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	330	426	359	463
Interest income recognized related to loans with impaired status	1	1	2	1
Home equity [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	2,791	2,529	3,022	2,440
Interest income recognized related to loans with impaired status	$ 13	$ 14	$ 28	$ 22