Loans and Allowance for Loan Losses (Details 8) (USD $)	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
Loans and Allowance for Loan Losses
Non-acquired OREO	$ 27,484,000	$ 18,022,000	$ 22,686,000	$ 17,264,000
Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	2,517,352,000	2,470,565,000	2,461,639,000
Non-acquired OREO	22,400,000	18,000,000	22,700,000
Classified assets	157,500,000	184,400,000	180,300,000
Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	2,237,803,000	2,133,852,000	2,109,779,000
Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	144,455,000	170,330,000	194,271,000
Non-acquired loans | Substandard and doubtful
Loans and Allowance for Loan Losses
Total loans	135,100,000	166,400,000	157,600,000
Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	134,991,000	166,383,000	157,569,000
Non-acquired loans | Doubtful
Loans and Allowance for Loan Losses
Total loans	103,000
Non-acquired loans | Commercial loans
Loans and Allowance for Loan Losses
Total loans	1,717,281,000	1,714,580,000	1,699,377,000
Non-acquired loans | Commercial loans | Pass
Loans and Allowance for Loan Losses
Total loans	1,501,045,000	1,445,299,000	1,416,828,000
Non-acquired loans | Commercial loans | Special mention
Loans and Allowance for Loan Losses
Total loans	111,680,000	134,332,000	155,354,000
Non-acquired loans | Commercial loans | Substandard
Loans and Allowance for Loan Losses
Total loans	104,477,000	134,949,000	127,195,000
Non-acquired loans | Commercial loans | Doubtful
Loans and Allowance for Loan Losses
Total loans	79,000
Non-acquired loans | Construction & Land Development
Loans and Allowance for Loan Losses
Total loans	273,606,000	310,845,000	316,072,000
Non-acquired loans | Construction & Land Development | Pass
Loans and Allowance for Loan Losses
Total loans	216,801,000	232,131,000	228,166,000
Non-acquired loans | Construction & Land Development | Special mention
Loans and Allowance for Loan Losses
Total loans	29,894,000	33,254,000	40,294,000
Non-acquired loans | Construction & Land Development | Substandard
Loans and Allowance for Loan Losses
Total loans	26,867,000	45,460,000	47,612,000
Non-acquired loans | Construction & Land Development | Doubtful
Loans and Allowance for Loan Losses
Total loans	44,000
Non-acquired loans | Commercial Non-owner Occupied
Loans and Allowance for Loan Losses
Total loans	278,935,000	299,698,000	304,616,000
Non-acquired loans | Commercial Non-owner Occupied | Pass
Loans and Allowance for Loan Losses
Total loans	223,235,000	231,954,000	233,283,000
Non-acquired loans | Commercial Non-owner Occupied | Special mention
Loans and Allowance for Loan Losses
Total loans	34,470,000	43,733,000	51,241,000
Non-acquired loans | Commercial Non-owner Occupied | Substandard
Loans and Allowance for Loan Losses
Total loans	21,230,000	24,011,000	20,092,000
Non-acquired loans | Commercial Owner Occupied
Loans and Allowance for Loan Losses
Total loans	787,623,000	742,890,000	719,791,000
Non-acquired loans | Commercial Owner Occupied | Pass
Loans and Allowance for Loan Losses
Total loans	716,283,000	656,914,000	635,881,000
Non-acquired loans | Commercial Owner Occupied | Special mention
Loans and Allowance for Loan Losses
Total loans	29,565,000	38,511,000	45,398,000
Non-acquired loans | Commercial Owner Occupied | Substandard
Loans and Allowance for Loan Losses
Total loans	41,740,000	47,465,000	38,512,000
Non-acquired loans | Commercial Owner Occupied | Doubtful
Loans and Allowance for Loan Losses
Total loans	35,000
Non-acquired loans | Commercial & Industrial
Loans and Allowance for Loan Losses
Total loans	245,285,000	220,454,000	216,573,000
Non-acquired loans | Commercial & Industrial | Pass
Loans and Allowance for Loan Losses
Total loans	230,317,000	207,063,000	200,996,000
Non-acquired loans | Commercial & Industrial | Special mention
Loans and Allowance for Loan Losses
Total loans	8,996,000	6,949,000	6,598,000
Non-acquired loans | Commercial & Industrial | Substandard
Loans and Allowance for Loan Losses
Total loans	5,972,000	6,442,000	8,979,000
Non-acquired loans | Other Income Producing Property
Loans and Allowance for Loan Losses
Total loans	131,832,000	140,693,000	142,325,000
Non-acquired loans | Other Income Producing Property | Pass
Loans and Allowance for Loan Losses
Total loans	114,409,000	117,237,000	118,502,000
Non-acquired loans | Other Income Producing Property | Special mention
Loans and Allowance for Loan Losses
Total loans	8,755,000	11,885,000	11,823,000
Non-acquired loans | Other Income Producing Property | Substandard
Loans and Allowance for Loan Losses
Total loans	8,668,000	11,571,000	12,000,000
Non-acquired loans | Consumer Total
Loans and Allowance for Loan Losses
Total loans	800,071,000	755,985,000	762,236,000
Non-acquired loans | Consumer Total | Pass
Loans and Allowance for Loan Losses
Total loans	736,758,000	688,553,000	692,971,000
Non-acquired loans | Consumer Total | Special mention
Loans and Allowance for Loan Losses
Total loans	32,775,000	35,998,000	38,917,000
Non-acquired loans | Consumer Total | Substandard
Loans and Allowance for Loan Losses
Total loans	30,514,000	31,434,000	30,374,000
Non-acquired loans | Consumer Total | Doubtful
Loans and Allowance for Loan Losses
Total loans	24,000
Non-acquired loans | Consumer Owner Occupied
Loans and Allowance for Loan Losses
Total loans	430,825,000	391,529,000	394,205,000
Non-acquired loans | Consumer Owner Occupied | Pass
Loans and Allowance for Loan Losses
Total loans	383,152,000	342,307,000	343,662,000
Non-acquired loans | Consumer Owner Occupied | Special mention
Loans and Allowance for Loan Losses
Total loans	23,556,000	25,298,000	28,348,000
Non-acquired loans | Consumer Owner Occupied | Substandard
Loans and Allowance for Loan Losses
Total loans	24,117,000	23,924,000	22,195,000
Non-acquired loans | Home Equity
Loans and Allowance for Loan Losses
Total loans	255,677,000	264,986,000	264,588,000
Non-acquired loans | Home Equity | Pass
Loans and Allowance for Loan Losses
Total loans	241,278,000	247,929,000	246,970,000
Non-acquired loans | Home Equity | Special mention
Loans and Allowance for Loan Losses
Total loans	8,420,000	10,018,000	9,904,000
Non-acquired loans | Home Equity | Substandard
Loans and Allowance for Loan Losses
Total loans	5,955,000	7,039,000	7,714,000
Non-acquired loans | Home Equity | Doubtful
Loans and Allowance for Loan Losses
Total loans	24,000
Non-acquired loans | Consumer
Loans and Allowance for Loan Losses
Total loans	86,729,000	85,342,000	84,972,000
Non-acquired loans | Consumer | Pass
Loans and Allowance for Loan Losses
Total loans	85,488,000	84,189,000	83,842,000
Non-acquired loans | Consumer | Special mention
Loans and Allowance for Loan Losses
Total loans	799,000	682,000	665,000
Non-acquired loans | Consumer | Substandard
Loans and Allowance for Loan Losses
Total loans	442,000	471,000	465,000
Non-acquired loans | Other Loans
Loans and Allowance for Loan Losses
Total loans	26,840,000	14,128,000	18,497,000
Non-acquired loans | Other Loans | Pass
Loans and Allowance for Loan Losses
Total loans	$ 26,840,000	$ 14,128,000	$ 18,497,000