Loans (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	$ 132,202	$ 159,006	$ 138,079	$ 160,894
Interest income recognized related to loans with impaired status	720	852	2,491	2,334
Commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	28,683	28,593	27,684	30,384
Interest income recognized related to loans with impaired status	149	260	602	730
Real estate commercial [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	54,524	70,634	59,063	71,854
Interest income recognized related to loans with impaired status	212	281	642	616
Real estate construction [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	912	145	470	192
Interest income recognized related to loans with impaired status	0	2	0	10
Land development [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	10,582	13,414	8,869	13,940
Interest income recognized related to loans with impaired status	71	86	216	270
Real estate residential [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	33,652	39,848	37,861	38,467
Interest income recognized related to loans with impaired status	288	223	1,031	708
Consumer installment [Member]
Schedule representing information related to impaired loans
Average recorded investment related to impaired loans	909	2,916	1,222	2,844
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	2,940	3,456	2,910	3,213
Interest income recognized related to loans with impaired status	$ 0	$ 0	$ 0	$ 0