Loans and Allowance for Loan Losses, Impaired Financing Receivable (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Financing Receivable, Impaired [Line Items]
Recorded investment	$ 22,823,000		$ 47,855,000		$ 80,863,000
Unpaid principal balance	35,057,000		58,981,000		93,570,000
Related allowance	1,764,000	[1]	4,440,000	[1]	8,957,000	[1]
Average recorded investment	38,413,000		60,792,000		93,687,000
Interest income recognized	0		42,000		1,331,000
Interest income from cash payments received			42,000		1,300,000
Collateral Dependent Impaired Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	15,474,000		28,546,000		48,891,000
Unpaid principal balance	21,404,000		34,699,000		58,903,000
Related allowance	0	[1]	0	[1]	0	[1]
Average recorded investment	21,547,000		35,567,000		59,019,000
Interest income recognized	0		42,000		558,000
Collateral Dependent Impaired Loans [Member] | Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	1,547,000		3,036,000		2,865,000
Unpaid principal balance	1,761,000		3,546,000		5,501,000
Related allowance	0	[1]	0	[1]	0	[1]
Average recorded investment	1,896,000		3,689,000		5,501,000
Interest income recognized	0		0		9,000
Collateral Dependent Impaired Loans [Member] | Construction and Land Development [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	1,546,000		6,917,000		31,106,000
Unpaid principal balance	2,062,000		9,093,000		35,525,000
Related allowance	0	[1]	0	[1]	0	[1]
Average recorded investment	2,063,000		9,288,000		35,631,000
Interest income recognized	0		37,000		188,000
Collateral Dependent Impaired Loans [Member] | Consumer Real Estate - Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	3,641,000		9,248,000		4,063,000
Unpaid principal balance	6,394,000		9,961,000		5,041,000
Related allowance	0	[1]	0	[1]	0	[1]
Average recorded investment	6,394,000		10,140,000		5,041,000
Interest income recognized	0		0		83,000
Collateral Dependent Impaired Loans [Member] | Commercial Real Estate - Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	8,740,000		9,345,000		10,585,000
Unpaid principal balance	11,187,000		12,099,000		12,468,000
Related allowance	0	[1]	0	[1]	0	[1]
Average recorded investment	11,194,000		12,450,000		12,478,000
Interest income recognized	0		5,000		278,000
Collateral Dependent Impaired Loans [Member] | Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0		272,000
Unpaid principal balance	0		0		368,000
Related allowance	0	[1]	0	[1]	0	[1]
Average recorded investment	0		0		368,000
Interest income recognized	0		0		0
Cash Flow Dependent Impaired Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	7,349,000		19,309,000		31,972,000
Unpaid principal balance	13,653,000		24,282,000		34,667,000
Related allowance	1,764,000	[1]	4,440,000	[1]	8,957,000	[1]
Average recorded investment	16,866,000		25,225,000		34,668,000
Interest income recognized	0		0		773,000
Cash Flow Dependent Impaired Loans [Member] | Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	1,491,000		8,854,000		11,875,000
Unpaid principal balance	2,459,000		11,041,000		13,005,000
Related allowance	814,000	[1]	2,767,000	[1]	3,825,000	[1]
Average recorded investment	2,528,000		11,497,000		12,996,000
Interest income recognized	0		0		324,000
Cash Flow Dependent Impaired Loans [Member] | Construction and Land Development [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	2,963,000		6,048,000		12,408,000
Unpaid principal balance	4,701,000		6,822,000		12,619,000
Related allowance	201,000	[1]	1,264,000	[1]	568,000	[1]
Average recorded investment	5,102,000		7,074,000		12,623,000
Interest income recognized	0		0		234,000
Cash Flow Dependent Impaired Loans [Member] | Consumer Real Estate - Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	2,265,000		3,239,000		4,972,000
Unpaid principal balance	4,473,000		4,902,000		5,869,000
Related allowance	573,000	[1]	301,000	[1]	3,998,000	[1]
Average recorded investment	5,828,000		5,005,000		5,875,000
Interest income recognized	0		0		143,000
Cash Flow Dependent Impaired Loans [Member] | Commercial Real Estate - Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	551,000		617,000		1,957,000
Unpaid principal balance	1,841,000		661,000		2,328,000
Related allowance	154,000	[1]	57,000	[1]	176,000	[1]
Average recorded investment	3,228,000		792,000		2,328,000
Interest income recognized	0		0		55,000
Cash Flow Dependent Impaired Loans [Member] | Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment	79,000		551,000		760,000
Unpaid principal balance	179,000		856,000		846,000
Related allowance	22,000	[1]	51,000	[1]	390,000	[1]
Average recorded investment	180,000		857,000		846,000
Interest income recognized	$ 0		$ 0		$ 17,000

[1] Collateral dependent loans are typically charged-off to their net realizable value pursuant to requirements of our primary regulators and no specific allowance is carried related to those loans.