Loans and Allowance for Loan Losses, Part II (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum Balance Of Loans For Which Credit Quality Analysis Is Performed	$ 100,000		$ 100,000
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	2,542,000		2,542,000		2,899,000
60 to 89 Days Past Due	943,000		943,000		521,000
90 Days or More Past Due	2,590,000		2,590,000		3,263,000
Total Past Due	6,075,000		6,075,000		6,683,000
Current	893,292,000		893,292,000		853,391,000
Total Loans Receivable	899,367,000		899,367,000		860,074,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	2,227,000		2,227,000		2,700,000
Unpaid Principal Balance	2,642,000		2,642,000		3,216,000
Specific Allowance	768,000		768,000		575,000
Loans without a specific allowance [Abstract]
Recorded Balance	5,617,000		5,617,000		4,740,000
Unpaid Principal Balance	6,255,000		6,255,000		5,554,000
Total Loans [Abstract]
Recorded Balance	7,844,000		7,844,000		7,440,000
Unpaid Principal Balance	8,897,000		8,897,000		8,770,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	8,106,000	9,814,000	8,198,000	10,005,000
Interest income recognized	10,000	10,000	32,000	26,000
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	7,132,000		7,132,000		6,723,000
Interest Lost on Nonaccrual Loans			165,000	361,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	3,530,000		3,530,000		1,834,000
Troubled Debt Restructuring, Allowance	459,000		459,000		140,000
Number of restructured notes	2		2
Number of non-accrual notes	3		3
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	3,530,000		3,530,000		1,834,000
Financing Receivable Modifications Performing Recorded Investment	712,000		712,000		717,000
Subsequent Default, Number of Contracts					2
Subsequent Default, Troubled Debt Restructurings					215,000
Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	848,913,000		848,913,000		809,177,000
Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	33,024,000		33,024,000		31,945,000
Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	17,430,000		17,430,000		18,952,000
Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Construction and Land Development [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	758,000		758,000		0
60 to 89 Days Past Due	0		0		0
90 Days or More Past Due	0		0		0
Total Past Due	758,000		758,000		0
Current	24,359,000		24,359,000		23,136,000
Total Loans Receivable	25,117,000		25,117,000		23,136,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	397,000		397,000		833,000
Unpaid Principal Balance	812,000		812,000		1,070,000
Specific Allowance	206,000		206,000		295,000
Loans without a specific allowance [Abstract]
Recorded Balance	1,156,000		1,156,000		0
Unpaid Principal Balance	1,257,000		1,257,000		0
Total Loans [Abstract]
Recorded Balance	1,553,000		1,553,000		833,000
Unpaid Principal Balance	2,069,000		2,069,000		1,070,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	1,750,000	1,174,000	1,736,000	1,179,000
Interest income recognized	0	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	1,553,000		1,553,000		833,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	1,554,000		1,554,000		0
Number of restructured notes	4		4
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	1,554,000		1,554,000		0
Construction and Land Development [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	20,949,000		20,949,000		19,708,000
Construction and Land Development [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,147,000		2,147,000		2,168,000
Construction and Land Development [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,021,000		2,021,000		1,260,000
Construction and Land Development [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Farm Loans [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	493,000		493,000		377,000
60 to 89 Days Past Due	0		0		111,000
90 Days or More Past Due	70,000		70,000		737,000
Total Past Due	563,000		563,000		1,225,000
Current	82,862,000		82,862,000		71,360,000
Total Loans Receivable	83,425,000		83,425,000		72,585,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Specific Allowance	0		0		0
Loans without a specific allowance [Abstract]
Recorded Balance	199,000		199,000		532,000
Unpaid Principal Balance	210,000		210,000		532,000
Total Loans [Abstract]
Recorded Balance	199,000		199,000		532,000
Unpaid Principal Balance	210,000		210,000		532,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	199,000	533,000	199,000	534,000
Interest income recognized	0	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	199,000		199,000		532,000
Farm Loans [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	78,781,000		78,781,000		67,637,000
Farm Loans [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,472,000		2,472,000		2,496,000
Farm Loans [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,172,000		2,172,000		2,452,000
Farm Loans [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
1-4 Family Residential Properties [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	391,000		391,000		1,079,000
60 to 89 Days Past Due	240,000		240,000		200,000
90 Days or More Past Due	1,345,000		1,345,000		1,033,000
Total Past Due	1,976,000		1,976,000		2,312,000
Current	188,263,000		188,263,000		179,537,000
Total Loans Receivable	190,239,000		190,239,000		181,849,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	489,000		489,000		71,000
Unpaid Principal Balance	489,000		489,000		71,000
Specific Allowance	58,000		58,000		27,000
Loans without a specific allowance [Abstract]
Recorded Balance	1,459,000		1,459,000		1,641,000
Unpaid Principal Balance	1,790,000		1,790,000		1,818,000
Total Loans [Abstract]
Recorded Balance	1,948,000		1,948,000		1,712,000
Unpaid Principal Balance	2,279,000		2,279,000		1,889,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	1,972,000	2,231,000	1,982,000	2,242,000
Interest income recognized	0	0	0	0
Loans Receivable, Modifications, Still Accruing Interest	6,000		6,000
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	1,941,000		1,941,000		1,712,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	462,000		462,000		393,000
Number of restructured notes	1		1
Extension period of modified loan			6
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	462,000		462,000		393,000
Financing Receivable Modifications Performing Recorded Investment	6,000		6,000		0
1-4 Family Residential Properties [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	187,434,000		187,434,000		180,247,000
1-4 Family Residential Properties [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	430,000		430,000		497,000
1-4 Family Residential Properties [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	2,375,000		2,375,000		1,105,000
1-4 Family Residential Properties [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Multifamily Residential Properties [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	207,000		207,000		0
60 to 89 Days Past Due	0		0		0
90 Days or More Past Due	0		0		0
Total Past Due	207,000		207,000		0
Current	44,085,000		44,085,000		19,846,000
Total Loans Receivable	44,292,000		44,292,000		19,846,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Specific Allowance	0		0		0
Loans without a specific allowance [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Total Loans [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	0	0	0	0
Interest income recognized	0	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	0		0		0
Multifamily Residential Properties [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	44,085,000		44,085,000		19,638,000
Multifamily Residential Properties [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Multifamily Residential Properties [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	207,000		207,000		208,000
Multifamily Residential Properties [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Commercial Real Estate [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	223,000		223,000		399,000
60 to 89 Days Past Due	478,000		478,000		101,000
90 Days or More Past Due	238,000		238,000		228,000
Total Past Due	939,000		939,000		728,000
Current	312,091,000		312,091,000		320,273,000
Total Loans Receivable	313,030,000		313,030,000		321,001,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	592,000		592,000		1,414,000
Unpaid Principal Balance	592,000		592,000		1,693,000
Specific Allowance	119,000		119,000		183,000
Loans without a specific allowance [Abstract]
Recorded Balance	1,699,000		1,699,000		1,226,000
Unpaid Principal Balance	1,720,000		1,720,000		1,256,000
Total Loans [Abstract]
Recorded Balance	2,291,000		2,291,000		2,640,000
Unpaid Principal Balance	2,312,000		2,312,000		2,949,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	2,299,000	3,934,000	2,319,000	3,968,000
Interest income recognized	7,000	7,000	21,000	15,000
Loans Receivable, Modifications, Still Accruing Interest	388,000	396,000	388,000	396,000
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	1,903,000		1,903,000		2,245,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	1,011,000		1,011,000		952,000
Number of restructured notes		1		1
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	1,011,000		1,011,000		952,000
Financing Receivable Modifications Performing Recorded Investment	388,000		388,000		395,000
Commercial Real Estate [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	283,605,000		283,605,000		288,539,000
Commercial Real Estate [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	24,465,000		24,465,000		24,664,000
Commercial Real Estate [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	4,960,000		4,960,000		7,798,000
Commercial Real Estate [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Agricultural Loans [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	242,000		242,000		0
60 to 89 Days Past Due	0		0		0
90 Days or More Past Due	704,000		704,000		673,000
Total Past Due	946,000		946,000		673,000
Current	62,419,000		62,419,000		62,584,000
Total Loans Receivable	63,365,000		63,365,000		63,257,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Specific Allowance	0		0		0
Loans without a specific allowance [Abstract]
Recorded Balance	822,000		822,000		673,000
Unpaid Principal Balance	822,000		822,000		673,000
Total Loans [Abstract]
Recorded Balance	822,000		822,000		673,000
Unpaid Principal Balance	822,000		822,000		673,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	837,000	695,000	867,000	695,000
Interest income recognized	0	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	823,000		823,000		673,000
Agricultural Loans [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	57,912,000		57,912,000		58,133,000
Agricultural Loans [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,542,000		1,542,000		1,840,000
Agricultural Loans [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	3,911,000		3,911,000		3,284,000
Agricultural Loans [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Commercial and Industrial Loans [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	148,000		148,000		950,000
60 to 89 Days Past Due	155,000		155,000		73,000
90 Days or More Past Due	218,000		218,000		585,000
Total Past Due	521,000		521,000		1,608,000
Current	153,780,000		153,780,000		149,108,000
Total Loans Receivable	154,301,000		154,301,000		150,716,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	749,000		749,000		382,000
Unpaid Principal Balance	749,000		749,000		382,000
Specific Allowance	385,000		385,000		70,000
Loans without a specific allowance [Abstract]
Recorded Balance	253,000		253,000		660,000
Unpaid Principal Balance	421,000		421,000		1,255,000
Total Loans [Abstract]
Recorded Balance	1,002,000		1,002,000		1,042,000
Unpaid Principal Balance	1,170,000		1,170,000		1,637,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	1,019,000	1,242,000	1,063,000	1,382,000
Interest income recognized	3,000	3,000	10,000	11,000
Loans Receivable, Modifications, Still Accruing Interest	304,000		304,000
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	698,000		698,000		720,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	489,000		489,000		489,000
Number of restructured notes	4	1	4	1
Percentage of loans guaranteed by the Small Business Administration			75.00%
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	489,000		489,000		489,000
Financing Receivable Modifications Performing Recorded Investment	304,000		304,000		322,000
Commercial and Industrial Loans [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	150,578,000		150,578,000		147,591,000
Commercial and Industrial Loans [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,953,000		1,953,000		280,000
Commercial and Industrial Loans [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	1,770,000		1,770,000		2,845,000
Commercial and Industrial Loans [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Consumer Loans [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	80,000		80,000		94,000
60 to 89 Days Past Due	70,000		70,000		36,000
90 Days or More Past Due	15,000		15,000		7,000
Total Past Due	165,000		165,000		137,000
Current	16,077,000		16,077,000		16,134,000
Total Loans Receivable	16,242,000		16,242,000		16,271,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Specific Allowance	0		0		0
Loans without a specific allowance [Abstract]
Recorded Balance	29,000		29,000		8,000
Unpaid Principal Balance	35,000		35,000		20,000
Total Loans [Abstract]
Recorded Balance	29,000		29,000		8,000
Unpaid Principal Balance	35,000		35,000		20,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	30,000	5,000	32,000	5,000
Interest income recognized	0	0	1,000	0
Loans Receivable, Modifications, Still Accruing Interest	14,000		14,000
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	15,000		15,000		8,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	14,000		14,000		0
Number of restructured notes	1		1
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	14,000		14,000		0
Financing Receivable Modifications Performing Recorded Investment	14,000		14,000		0
Consumer Loans [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	16,213,000		16,213,000		16,271,000
Consumer Loans [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	15,000		15,000		0
Consumer Loans [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	14,000		14,000		0
Consumer Loans [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
All Other Loans [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	0		0		0
60 to 89 Days Past Due	0		0		0
90 Days or More Past Due	0		0		0
Total Past Due	0		0		0
Current	9,356,000		9,356,000		11,413,000
Total Loans Receivable	9,356,000		9,356,000		11,413,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Specific Allowance	0		0		0
Loans without a specific allowance [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Total Loans [Abstract]
Recorded Balance	0		0		0
Unpaid Principal Balance	0		0		0
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	0	0	0	0
Interest income recognized	0	0	0	0
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	0		0		0
All Other Loans [Member] | Pass [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	9,356,000		9,356,000		11,413,000
All Other Loans [Member] | Watch [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
All Other Loans [Member] | Substandard [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
All Other Loans [Member] | Doubtful [Member]
Loans Receivable Aging Analysis [Abstract]
Total Loans Receivable	0		0		0
Loans Secured by Real Estate [Member]
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due	2,072,000		2,072,000		1,855,000
60 to 89 Days Past Due	718,000		718,000		412,000
90 Days or More Past Due	1,653,000		1,653,000		1,998,000
Total Past Due	4,443,000		4,443,000		4,265,000
Current	651,660,000		651,660,000		614,152,000
Total Loans Receivable	656,103,000		656,103,000		618,417,000
Total Loans Greater than 90 Days Past Due and Still Accruing	0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance	1,478,000		1,478,000		2,318,000
Unpaid Principal Balance	1,893,000		1,893,000		2,834,000
Specific Allowance	383,000		383,000		505,000
Loans without a specific allowance [Abstract]
Recorded Balance	4,513,000		4,513,000		3,399,000
Unpaid Principal Balance	4,977,000		4,977,000		3,606,000
Total Loans [Abstract]
Recorded Balance	5,991,000		5,991,000		5,717,000
Unpaid Principal Balance	6,870,000		6,870,000		6,440,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	6,220,000	7,872,000	6,236,000	7,923,000
Interest income recognized	7,000	7,000	21,000	15,000
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	5,596,000		5,596,000		5,322,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	3,027,000		3,027,000		1,345,000
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	3,027,000		3,027,000		1,345,000
Financing Receivable Modifications Performing Recorded Investment	$ 394,000		$ 394,000		$ 395,000