Loans and the Allowance for Credit Losses (Details 6) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	$ 39,952	$ 57,492
TDRs	39,324	46,698
Commercial Real Estate Land and Construction [Member]
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	5,158	10,135
TDRs	9,592	13,072
Commercial Real Estate Improved Property [Member]
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	18,643	25,122
TDRs	23,251	25,716
Commercial and Industrial [Member]
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	5,302	8,238
TDRs	1,414	3,353
Residential Real Estate [Member]
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	9,766	12,377
TDRs	5,067	4,557
Home Equity [Member]
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	908	1,331
TDRs	0	0
Consumer [Member]
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	175	289
TDRs	0	0
Commercial Real Estate [Member]
Recorded Investment in Non-Accrual Loans and TDRs
Non-accrual loans	23,801	35,257
TDRs	32,843	38,788
Non Accrual Tdrs [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	11,159	17,287
Non Accrual Tdrs [Member] | Commercial Real Estate Land and Construction [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	2,689	5,662
Non Accrual Tdrs [Member] | Commercial Real Estate Improved Property [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	6,871	8,398
Non Accrual Tdrs [Member] | Commercial and Industrial [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	573	2,514
Non Accrual Tdrs [Member] | Residential Real Estate [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	1,026	713
Non Accrual Tdrs [Member] | Home Equity [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	0	0
Non Accrual Tdrs [Member] | Consumer [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	0	0
Non Accrual Tdrs [Member] | Commercial Real Estate [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	9,560	14,060
Accruing Tdrs [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	28,165	29,411
Accruing Tdrs [Member] | Commercial Real Estate Land and Construction [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	6,903	7,410
Accruing Tdrs [Member] | Commercial Real Estate Improved Property [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	16,380	17,318
Accruing Tdrs [Member] | Commercial and Industrial [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	841	839
Accruing Tdrs [Member] | Residential Real Estate [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	4,041	3,844
Accruing Tdrs [Member] | Home Equity [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	0	0
Accruing Tdrs [Member] | Consumer [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	0	0
Accruing Tdrs [Member] | Commercial Real Estate [Member]
Recorded Investment in Non-Accrual Loans and TDRs
TDRs	$ 23,283	$ 24,728