Acquired Loans (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Less allowance for loan losses, acquired loans	$ (4,343)	$ (502)
Net acquired loans	143,270	76,302
Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	64,503	76,804
Less allowance for loan losses, acquired loans	3,526	502
Net acquired loans	60,977	76,302
Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	83,110	4,363	[1]
Less allowance for loan losses, acquired loans	817	0	[1]
Net acquired loans	82,293	4,363	[1]
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	3,714	4,209
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	11,504	0	[1]
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	24,949	31,874
Real Estate Secured Financing Receivable [Member] | Residential Financing Receivable [Member] | Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	18,032	76	[1]
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	28,291	30,889
Real Estate Secured Financing Receivable [Member] | Nonresidential Properties Financing Receivables [Member] | Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	47,114	0	[1]
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	4,198	5,126
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	378	0	[1]
Commercial And Industrial Loans [Member] | Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	1,803	2,971
Commercial And Industrial Loans [Member] | Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	3,371	69	[1]
Consumer Loans Financing Receivable [Member] | Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	172	290
Consumer Loans Financing Receivable [Member] | Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	2,575	4,146	[1]
Other Loans Financing Receivable [Member] | Covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	1,376	1,445
Other Loans Financing Receivable [Member] | Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	$ 136	$ 72	[1]

[1] Acquired noncovered loans were included in LHFI at December 31, 2011.