(Summary of nonperforming loans) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Summary of nonperforming loans
Total nonperforming TDRs	$ 94,943	$ 96,060
Total loans	4,647,621	4,167,735
Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	61,897	71,298
Total accruing loans contractually past due 90 days or more as to interest or principal payments	1,997	2,359
Commercial Loan Portfolio [Member]
Summary of nonperforming loans
Total nonperforming TDRs	72,214	72,376
Total loans	2,518,826	2,264,820
Consumer Loan Portfolio [Member]
Summary of nonperforming loans
Total nonperforming TDRs	22,729	23,684
Total loans	2,128,795	1,902,915
Commercial [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	18,374	14,601
Total accruing loans contractually past due 90 days or more as to interest or principal payments	536	0
Real estate commercial [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	28,598	37,660
Total accruing loans contractually past due 90 days or more as to interest or principal payments	190	87
Real Estate Construction Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	371	1,217
Total accruing loans contractually past due 90 days or more as to interest or principal payments	0	0
Land Development Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	2,309	4,184
Total accruing loans contractually past due 90 days or more as to interest or principal payments	0	0
Real estate residential [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	8,921	10,164
Total accruing loans contractually past due 90 days or more as to interest or principal payments	537	1,503
Consumer Installment Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	676	739
Total accruing loans contractually past due 90 days or more as to interest or principal payments	0	0
Home Equity Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	2,648	2,733
Total accruing loans contractually past due 90 days or more as to interest or principal payments	734	769
Nonperforming [Member]
Summary of nonperforming loans
Total nonaccrual loans	61,897	71,298
Total accruing loans contractually past due 90 days or more as to interest or principal payments	1,997	2,359
Total nonperforming TDRs	18,090	17,197
Total loans	81,984	90,854
Nonperforming [Member] | Commercial Loan Portfolio [Member]
Summary of nonperforming loans
Total nonperforming TDRs	13,414	13,876
Nonperforming [Member] | Consumer Loan Portfolio [Member]
Summary of nonperforming loans
Total nonperforming TDRs	4,676	3,321
Nonperforming [Member] | Commercial [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	18,374	14,601
Total accruing loans contractually past due 90 days or more as to interest or principal payments	536	0
Nonperforming [Member] | Real estate commercial [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	28,598	37,660
Total accruing loans contractually past due 90 days or more as to interest or principal payments	190	87
Nonperforming [Member] | Real Estate Construction Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	371	1,217
Nonperforming [Member] | Land Development Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	2,309	4,184
Nonperforming [Member] | Real estate residential [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	8,921	10,164
Total accruing loans contractually past due 90 days or more as to interest or principal payments	537	1,503
Nonperforming [Member] | Consumer Installment Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	676	739
Nonperforming [Member] | Home Equity Loans [Member] | Originated Portfolio Segment [Member]
Summary of nonperforming loans
Total nonaccrual loans	2,648	2,733
Total accruing loans contractually past due 90 days or more as to interest or principal payments	$ 734	$ 769