Loans and Allowance for Loan Losses, Financing Receivables Past Due (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 To 89 days past due and accruing	$ 14,017,000		$ 12,950,000
90 days or more past due and accruing	83,000		3,346,000
Total past due and accruing	14,100,000		16,296,000
Nonaccrual	21,652,000	[1]	18,183,000	[1]
Current and accruing	4,385,499,000		4,110,014,000
Total Loans	4,421,251,000		4,144,493,000
Currently performing impaired loans	15,600,000		10,900,000
Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 To 89 days past due and accruing	245,000		2,534,000
90 days or more past due and accruing	0		0
Total past due and accruing	245,000		2,534,000
Nonaccrual	7,486,000	[1]	7,750,000	[1]
Current and accruing	720,352,000		669,014,000
Total Loans	728,083,000		679,298,000
Commercial Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 To 89 days past due and accruing	0		27,000
90 days or more past due and accruing	0		2,232,000
Total past due and accruing	0		2,259,000
Nonaccrual	0	[1]	1,267,000	[1]
Current and accruing	750,786,000		700,611,000
Total Loans	750,786,000		704,137,000
Consumer Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 To 89 days past due and accruing	4,327,000		2,215,000
90 days or more past due and accruing	0		0
Total past due and accruing	4,327,000		2,215,000
Nonaccrual	6,248,000	[1]	5,289,000	[1]
Current and accruing	696,226,000		688,112,000
Total Loans	706,801,000		695,616,000
Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 To 89 days past due and accruing	863,000		4,839,000
90 days or more past due and accruing	0		0
Total past due and accruing	863,000		4,839,000
Nonaccrual	5,474,000	[1]	1,070,000	[1]
Current and accruing	315,753,000		310,282,000
Total Loans	322,090,000		316,191,000
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 To 89 days past due and accruing	3,615,000		1,847,000
90 days or more past due and accruing	75,000		825,000
Total past due and accruing	3,690,000		2,672,000
Nonaccrual	1,948,000	[1]	2,565,000	[1]
Current and accruing	1,718,448,000		1,600,310,000
Total Loans	1,724,086,000		1,605,547,000
Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 To 89 days past due and accruing	4,967,000		1,488,000
90 days or more past due and accruing	8,000		289,000
Total past due and accruing	4,975,000		1,777,000
Nonaccrual	496,000	[1]	242,000	[1]
Current and accruing	183,934,000		141,685,000
Total Loans	$ 189,405,000		$ 143,704,000

[1] Approximately $15.6 million and $10.9 million of nonaccrual loans as of September 30, 2014 and December 31, 2013, respectively, were performing pursuant to their contractual terms at those dates.