Loans and Allowance for Loan Losses, Part II (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum Balance Of Loans For Which Credit Quality Analysis Is Performed	$ 100
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	2,737	2,899
60 to 89 Days Past Due	1,303	521
90 Days or More Past Due	2,204	3,263
Total Past Due	6,244	6,683
Current	904,821	853,391
Total Loans Receivable	911,065	860,074
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Number of days past due when interest is not accrued	ninety days
Period of satisfactory performance before returning to accrual status	six months
Loans with a specific allowance [Abstract]
Recorded Balance	2,060	2,700
Unpaid Principal Balance	2,562	3,216
Specific Allowance	511	575
Loans without a specific allowance [Abstract]
Recorded Balance	5,533	4,740
Unpaid Principal Balance	6,794	5,554
Total Loans [Abstract]
Recorded Balance	7,593	7,440
Unpaid Principal Balance	9,356	8,770
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	7,871	7,698	13,282
Interest income recognized	22	36	75
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	7,573	6,723
Interest Lost on Nonaccrual Loans	173,000	239,000	428,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	3,339	1,834
Troubled Debt Restructuring, Allowance	295	140
Number of restructured notes	2
Number of non-accrual notes	3
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	3,339	1,834
Financing Receivable Modifications Performing Recorded Investment	20	717
Subsequent Default, Number of Contracts		2
Subsequent Default, Troubled Debt Restructurings		215
Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	865,059	809,177
Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	31,994	31,945
Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	14,012	18,952
Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Construction and land development
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	0	0
60 to 89 Days Past Due	53	0
90 Days or More Past Due	0	0
Total Past Due	53	0
Current	31,288	23,136
Total Loans Receivable	31,341	23,136
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	1,114	833
Unpaid Principal Balance	1,529	1,070
Specific Allowance	295	295
Loans without a specific allowance [Abstract]
Recorded Balance	408	0
Unpaid Principal Balance	694	0
Total Loans [Abstract]
Recorded Balance	1,522	833
Unpaid Principal Balance	2,223	1,070
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	1,520	841	1,975
Interest income recognized	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	1,522	833
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	1,522	0
Number of restructured notes	4
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	1,522	0
Construction and land development | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	27,217	19,708
Construction and land development | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,135	2,168
Construction and land development | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,989	1,260
Construction and land development | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Farm loans
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	592	377
60 to 89 Days Past Due	0	111
90 Days or More Past Due	293	737
Total Past Due	885	1,225
Current	85,386	71,360
Total Loans Receivable	86,271	72,585
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Specific Allowance	0	0
Loans without a specific allowance [Abstract]
Recorded Balance	418	532
Unpaid Principal Balance	429	532
Total Loans [Abstract]
Recorded Balance	418	532
Unpaid Principal Balance	429	532
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	421	532	1,317
Interest income recognized	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	418	532
Farm loans | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	82,516	67,637
Farm loans | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,662	2,496
Farm loans | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,093	2,452
Farm loans | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
1-4 Family residential properties
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	1,351	1,079
60 to 89 Days Past Due	40	200
90 Days or More Past Due	944	1,033
Total Past Due	2,335	2,312
Current	184,163	179,537
Total Loans Receivable	186,498	181,849
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	636	71
Unpaid Principal Balance	723	71
Specific Allowance	162	27
Loans without a specific allowance [Abstract]
Recorded Balance	1,269	1,641
Unpaid Principal Balance	1,792	1,818
Total Loans [Abstract]
Recorded Balance	1,905	1,712
Unpaid Principal Balance	2,515	1,889
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	1,948	1,755	2,720
Interest income recognized	7	0	0
Loans Receivable, Modifications, Still Accruing Interest	6
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	1,899	1,712
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	445	393
Number of restructured notes	1
Extension period of modified loan	6
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	445	393
Financing Receivable Modifications Performing Recorded Investment	6	0
1-4 Family residential properties | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	183,880	180,247
1-4 Family residential properties | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	424	497
1-4 Family residential properties | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,194	1,105
1-4 Family residential properties | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Multifamily residential properties
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	0	0
60 to 89 Days Past Due	0	0
90 Days or More Past Due	0	0
Total Past Due	0	0
Current	44,863	19,846
Total Loans Receivable	44,863	19,846
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Specific Allowance	0	0
Loans without a specific allowance [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Total Loans [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	0	0	670
Interest income recognized	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	0	0
Multifamily residential properties | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	44,863	19,638
Multifamily residential properties | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Multifamily residential properties | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	208
Multifamily residential properties | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Commercial real estate
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	262	399
60 to 89 Days Past Due	911	101
90 Days or More Past Due	255	228
Total Past Due	1,428	728
Current	314,894	320,273
Total Loans Receivable	316,322	321,001
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	0	1,414
Unpaid Principal Balance	0	1,693
Specific Allowance	0	183
Loans without a specific allowance [Abstract]
Recorded Balance	2,063	1,226
Unpaid Principal Balance	2,253	1,256
Total Loans [Abstract]
Recorded Balance	2,063	2,640
Unpaid Principal Balance	2,253	2,949
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	2,100	2,688	4,425
Interest income recognized	0	22	56
Loans Receivable, Modifications, Still Accruing Interest	0	395
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	2,063	2,245
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	950	952
Number of restructured notes		1
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	950	952
Financing Receivable Modifications Performing Recorded Investment	0	395
Commercial real estate | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	287,794	288,539
Commercial real estate | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	24,213	24,664
Commercial real estate | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	4,315	7,798
Commercial real estate | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Loans secured by real estate
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	2,205	1,855
60 to 89 Days Past Due	1,004	412
90 Days or More Past Due	1,492	1,998
Total Past Due	4,701	4,265
Current	660,594	614,152
Total Loans Receivable	665,295	618,417
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	1,750	2,318
Unpaid Principal Balance	2,252	2,834
Specific Allowance	457	505
Loans without a specific allowance [Abstract]
Recorded Balance	4,158	3,399
Unpaid Principal Balance	5,168	3,606
Total Loans [Abstract]
Recorded Balance	5,908	5,717
Unpaid Principal Balance	7,420	6,440
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	5,989	5,816	11,107
Interest income recognized	7	22	56
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	5,902	5,322
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	2,917	1,345
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	2,917	1,345
Financing Receivable Modifications Performing Recorded Investment	6	395
Agricultural loans
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	0	0
60 to 89 Days Past Due	0	0
90 Days or More Past Due	620	673
Total Past Due	620	673
Current	60,394	62,584
Total Loans Receivable	61,014	63,257
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	310	0
Unpaid Principal Balance	310	0
Specific Allowance	54	0
Loans without a specific allowance [Abstract]
Recorded Balance	620	673
Unpaid Principal Balance	1,568	673
Total Loans [Abstract]
Recorded Balance	930	673
Unpaid Principal Balance	1,878	673
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	1,071	673	993
Interest income recognized	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	930	673
Agricultural loans | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	56,899	58,133
Agricultural loans | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	958	1,840
Agricultural loans | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	3,157	3,284
Agricultural loans | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Commercial and industrial loans
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	413	950
60 to 89 Days Past Due	275	73
90 Days or More Past Due	53	585
Total Past Due	741	1,608
Current	159,558	149,108
Total Loans Receivable	160,299	150,716
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	0	382
Unpaid Principal Balance	0	382
Specific Allowance	0	70
Loans without a specific allowance [Abstract]
Recorded Balance	704	660
Unpaid Principal Balance	0	1,255
Total Loans [Abstract]
Recorded Balance	704	1,042
Unpaid Principal Balance	0	1,637
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	755	1,199	1,165
Interest income recognized	0	14	19
Loans Receivable, Modifications, Still Accruing Interest	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	704	720
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	408	489
Number of restructured notes	4	1
Percentage of loans guaranteed by the Small Business Administration	75.00%
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	408	489
Financing Receivable Modifications Performing Recorded Investment	0	322
Commercial and industrial loans | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	157,461	147,591
Commercial and industrial loans | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,588	280
Commercial and industrial loans | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,250	2,845
Commercial and industrial loans | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
Consumer loans
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	119	94
60 to 89 Days Past Due	24	36
90 Days or More Past Due	39	7
Total Past Due	182	137
Current	16,082	16,134
Total Loans Receivable	16,264	16,271
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Specific Allowance	0	0
Loans without a specific allowance [Abstract]
Recorded Balance	51	8
Unpaid Principal Balance	58	20
Total Loans [Abstract]
Recorded Balance	51	8
Unpaid Principal Balance	58	20
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	56	10	17
Interest income recognized	15	0	0
Loans Receivable, Modifications, Still Accruing Interest	14
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	37	8
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	14	0
Number of restructured notes	1
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	14	0
Financing Receivable Modifications Performing Recorded Investment	14	0
Consumer loans | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	16,236	16,271
Consumer loans | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	14	0
Consumer loans | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	14	0
Consumer loans | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
All other loans
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	0	0
60 to 89 Days Past Due	0	0
90 Days or More Past Due	0	0
Total Past Due	0	0
Current	8,193	11,413
Total Loans Receivable	8,193	11,413
Total Loans Greater than 90 Days Past Due and Still Accruing	0	0
Loans with a specific allowance [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Specific Allowance	0	0
Loans without a specific allowance [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Total Loans [Abstract]
Recorded Balance	0	0
Unpaid Principal Balance	0	0
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	0	0	0
Interest income recognized	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	0	0
All other loans | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	8,193	11,413
All other loans | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
All other loans | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0	0
All other loans | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	$ 0	$ 0