Allowance For Loan Losses (Summary Of Net Unearned Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2009
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 17,933	$ 17,712	$ 17,712	$ 17,933	$ 17,712
Charge-offs	2,497	1,339	8,817
Recoveries	84	149	538
Provision	1,500	2,001	8,500
Ending balance	17,020	18,523	17,933	17,933	17,712
Allowance related to: Loans individually evaluated for impairment	6,465
Allowance related to: Loans collectively evaluated for impairment	10,555
Loans individually evaluated for impairment	89,146
Loans collectively evaluated for impairment	873,615
Total, Loans	962,761
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	782
Charge-offs	17	31	1,273
Recoveries	2	2	13
Provision	256
Ending balance	1,023		782
Allowance related to: Loans individually evaluated for impairment	403
Allowance related to: Loans collectively evaluated for impairment	620
Loans individually evaluated for impairment	10,486
Loans collectively evaluated for impairment	76,391
Total, Loans	86,877
Owner-Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,387
Charge-offs	63	283	636
Recoveries	2	3	33
Provision	53
Ending balance	1,379		1,387
Allowance related to: Loans individually evaluated for impairment	437
Allowance related to: Loans collectively evaluated for impairment	942
Loans individually evaluated for impairment	16,007
Loans collectively evaluated for impairment	135,935
Total, Loans	151,942
Non-Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	3,269
Charge-offs	3	395	806
Recoveries		8	31
Provision	(18)
Ending balance	3,248		3,269
Allowance related to: Loans individually evaluated for impairment	152
Allowance related to: Loans collectively evaluated for impairment	3,096
Loans individually evaluated for impairment	6,858
Loans collectively evaluated for impairment	281,617
Total, Loans	288,475
Land And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	5,220
Charge-offs	2,062	365	3,390
Recoveries	5	5	61
Provision	742
Ending balance	3,905		5,220
Allowance related to: Loans individually evaluated for impairment	1,421
Allowance related to: Loans collectively evaluated for impairment	2,484
Loans individually evaluated for impairment	28,051
Loans collectively evaluated for impairment	48,226
Total, Loans	76,277
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	138
Charge-offs			367
Recoveries
Provision	140
Ending balance	278		138
Allowance related to: Loans collectively evaluated for impairment	278
Loans collectively evaluated for impairment	5,782
Total, Loans	5,782
Non-Jumbo [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,617
Charge-offs	228	126	1,372
Recoveries	19	19	81
Provision	(76)
Ending balance	2,332		2,617
Allowance related to: Loans individually evaluated for impairment	303
Allowance related to: Loans collectively evaluated for impairment	2,029
Loans individually evaluated for impairment	6,019
Loans collectively evaluated for impairment	207,946
Total, Loans	213,965
Jumbo [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	3,942
Charge-offs	60	87	737
Recoveries	1	9	86
Provision	632
Ending balance	4,515		3,942
Allowance related to: Loans individually evaluated for impairment	3,707
Allowance related to: Loans collectively evaluated for impairment	808
Loans individually evaluated for impairment	21,450
Loans collectively evaluated for impairment	41,399
Total, Loans	62,849
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	425
Charge-offs	20		5
Recoveries		60	61
Provision	(179)
Ending balance	226		425
Allowance related to: Loans individually evaluated for impairment	28
Allowance related to: Loans collectively evaluated for impairment	198
Loans individually evaluated for impairment	213
Loans collectively evaluated for impairment	53,552
Total, Loans	53,765
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	132
Charge-offs	22	32	136
Recoveries	21	14	95
Provision	(26)
Ending balance	105		132
Allowance related to: Loans individually evaluated for impairment	14
Allowance related to: Loans collectively evaluated for impairment	91
Loans individually evaluated for impairment	62
Loans collectively evaluated for impairment	19,576
Total, Loans	19,638
Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	21
Charge-offs	22	20	95
Recoveries	34	29	77
Provision	(24)
Ending balance	9		21
Allowance related to: Loans collectively evaluated for impairment	9
Loans collectively evaluated for impairment	3,191
Total, Loans	$ 3,191