Loans and the Allowance for Loan Losses (Details 12) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investment in loans, net of unearned income on impairment methodology
Individually evaluated for impairment	$ 145,083	$ 166,692
Collectively evaluated for impairment	2,383,417	2,065,766
Acquired with deteriorated credit quality	271,663	348,626
Total loans, net of unearned income	2,800,163	2,581,084
Commercial [Member]
Investment in loans, net of unearned income on impairment methodology
Individually evaluated for impairment	3,391	6,271
Collectively evaluated for impairment	296,191	253,562
Acquired with deteriorated credit quality	11,474	18,258
Total loans, net of unearned income	311,056	278,091
Real Estate - Construction [Member]
Investment in loans, net of unearned income on impairment methodology
Individually evaluated for impairment	2,086	7,184
Collectively evaluated for impairment	101,436	66,975
Acquired with deteriorated credit quality	1,932	7,076
Total loans, net of unearned income	105,454	81,235
Real Estate - 1-4 Family Mortgage [Member]
Investment in loans, net of unearned income on impairment methodology
Individually evaluated for impairment	52,479	53,832
Collectively evaluated for impairment	747,398	661,339
Acquired with deteriorated credit quality	83,519	109,456
Total loans, net of unearned income	883,396	824,627
Real estate - commercial mortgage [Member]
Investment in loans, net of unearned income on impairment methodology
Individually evaluated for impairment	87,127	99,405
Collectively evaluated for impairment	1,181,790	1,027,838
Acquired with deteriorated credit quality	171,963	209,392
Total loans, net of unearned income	1,440,880	1,336,635
Installment and Other [Member]
Investment in loans, net of unearned income on impairment methodology
Individually evaluated for impairment
Collectively evaluated for impairment	56,602	56,052
Acquired with deteriorated credit quality	2,775	4,444
Total loans, net of unearned income	$ 59,377	$ 60,496