Loans and Allowance for Loan Losses, Part II (Details) (USD $)	3 Months Ended		6 Months Ended												3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended		12 Months Ended									3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended											3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Aug. 08, 2012	Dec. 31, 2011	Jun. 30, 2012 Pass [Member]	Dec. 31, 2011 Pass [Member]	Jun. 30, 2012 Watch [Member]	Dec. 31, 2011 Watch [Member]	Jun. 30, 2012 Substandard [Member]	Dec. 31, 2011 Substandard [Member]	Jun. 30, 2012 Doubtful [Member]	Dec. 31, 2011 Doubtful [Member]	Jun. 30, 2012 Construction and Land Development [Member]	Jun. 30, 2011 Construction and Land Development [Member]	Jun. 30, 2012 Construction and Land Development [Member]	Jun. 30, 2011 Construction and Land Development [Member]	Dec. 31, 2011 Construction and Land Development [Member]	Jun. 30, 2012 Construction and Land Development [Member] Pass [Member]	Dec. 31, 2011 Construction and Land Development [Member] Pass [Member]	Jun. 30, 2012 Construction and Land Development [Member] Watch [Member]	Dec. 31, 2011 Construction and Land Development [Member] Watch [Member]	Jun. 30, 2012 Construction and Land Development [Member] Substandard [Member]	Dec. 31, 2011 Construction and Land Development [Member] Substandard [Member]	Jun. 30, 2012 Construction and Land Development [Member] Doubtful [Member]	Dec. 31, 2011 Construction and Land Development [Member] Doubtful [Member]	Jun. 30, 2012 Farm Loans [Member]	Jun. 30, 2011 Farm Loans [Member]	Jun. 30, 2012 Farm Loans [Member]	Jun. 30, 2011 Farm Loans [Member]	Dec. 31, 2011 Farm Loans [Member]	Jun. 30, 2012 Farm Loans [Member] Pass [Member]	Dec. 31, 2011 Farm Loans [Member] Pass [Member]	Jun. 30, 2012 Farm Loans [Member] Watch [Member]	Dec. 31, 2011 Farm Loans [Member] Watch [Member]	Jun. 30, 2012 Farm Loans [Member] Substandard [Member]	Dec. 31, 2011 Farm Loans [Member] Substandard [Member]	Jun. 30, 2012 Farm Loans [Member] Doubtful [Member]	Dec. 31, 2011 Farm Loans [Member] Doubtful [Member]	Jun. 30, 2012 1-4 Family Residential Properties [Member]	Jun. 30, 2011 1-4 Family Residential Properties [Member]	Jun. 30, 2012 1-4 Family Residential Properties [Member]	Jun. 30, 2011 1-4 Family Residential Properties [Member]	Dec. 31, 2011 1-4 Family Residential Properties [Member]	Jun. 30, 2012 1-4 Family Residential Properties [Member] Pass [Member]	Dec. 31, 2011 1-4 Family Residential Properties [Member] Pass [Member]	Jun. 30, 2012 1-4 Family Residential Properties [Member] Watch [Member]	Dec. 31, 2011 1-4 Family Residential Properties [Member] Watch [Member]	Jun. 30, 2012 1-4 Family Residential Properties [Member] Substandard [Member]	Dec. 31, 2011 1-4 Family Residential Properties [Member] Substandard [Member]	Jun. 30, 2012 1-4 Family Residential Properties [Member] Doubtful [Member]	Dec. 31, 2011 1-4 Family Residential Properties [Member] Doubtful [Member]	Jun. 30, 2012 Multifamily Residential Properties [Member]	Jun. 30, 2011 Multifamily Residential Properties [Member]	Jun. 30, 2012 Multifamily Residential Properties [Member]	Jun. 30, 2011 Multifamily Residential Properties [Member]	Dec. 31, 2011 Multifamily Residential Properties [Member]	Jun. 30, 2012 Multifamily Residential Properties [Member] Pass [Member]	Dec. 31, 2011 Multifamily Residential Properties [Member] Pass [Member]	Jun. 30, 2012 Multifamily Residential Properties [Member] Watch [Member]	Dec. 31, 2011 Multifamily Residential Properties [Member] Watch [Member]	Jun. 30, 2012 Multifamily Residential Properties [Member] Substandard [Member]	Dec. 31, 2011 Multifamily Residential Properties [Member] Substandard [Member]	Jun. 30, 2012 Multifamily Residential Properties [Member] Doubtful [Member]	Dec. 31, 2011 Multifamily Residential Properties [Member] Doubtful [Member]	Jun. 30, 2012 Commercial Real Estate [Member]	Jun. 30, 2011 Commercial Real Estate [Member]	Jun. 30, 2012 Commercial Real Estate [Member]	Jun. 30, 2011 Commercial Real Estate [Member]	Dec. 31, 2011 Commercial Real Estate [Member]	Jun. 30, 2012 Commercial Real Estate [Member] Pass [Member]	Dec. 31, 2011 Commercial Real Estate [Member] Pass [Member]	Jun. 30, 2012 Commercial Real Estate [Member] Watch [Member]	Dec. 31, 2011 Commercial Real Estate [Member] Watch [Member]	Jun. 30, 2012 Commercial Real Estate [Member] Substandard [Member]	Dec. 31, 2011 Commercial Real Estate [Member] Substandard [Member]	Jun. 30, 2012 Commercial Real Estate [Member] Doubtful [Member]	Dec. 31, 2011 Commercial Real Estate [Member] Doubtful [Member]	Jun. 30, 2012 Agricultural Loans [Member]	Jun. 30, 2011 Agricultural Loans [Member]	Jun. 30, 2012 Agricultural Loans [Member]	Jun. 30, 2011 Agricultural Loans [Member]	Dec. 31, 2011 Agricultural Loans [Member]	Jun. 30, 2012 Agricultural Loans [Member] Pass [Member]	Dec. 31, 2011 Agricultural Loans [Member] Pass [Member]	Jun. 30, 2012 Agricultural Loans [Member] Watch [Member]	Dec. 31, 2011 Agricultural Loans [Member] Watch [Member]	Jun. 30, 2012 Agricultural Loans [Member] Substandard [Member]	Dec. 31, 2011 Agricultural Loans [Member] Substandard [Member]	Jun. 30, 2012 Agricultural Loans [Member] Doubtful [Member]	Dec. 31, 2011 Agricultural Loans [Member] Doubtful [Member]	Jun. 30, 2012 Commercial and Industrial Loans [Member]	Jun. 30, 2011 Commercial and Industrial Loans [Member]	Jun. 30, 2012 Commercial and Industrial Loans [Member]	Jun. 30, 2011 Commercial and Industrial Loans [Member]	Dec. 31, 2011 Commercial and Industrial Loans [Member]	Jun. 30, 2012 Commercial and Industrial Loans [Member] Pass [Member]	Dec. 31, 2011 Commercial and Industrial Loans [Member] Pass [Member]	Jun. 30, 2012 Commercial and Industrial Loans [Member] Watch [Member]	Dec. 31, 2011 Commercial and Industrial Loans [Member] Watch [Member]	Jun. 30, 2012 Commercial and Industrial Loans [Member] Substandard [Member]	Dec. 31, 2011 Commercial and Industrial Loans [Member] Substandard [Member]	Jun. 30, 2012 Commercial and Industrial Loans [Member] Doubtful [Member]	Dec. 31, 2011 Commercial and Industrial Loans [Member] Doubtful [Member]	Jun. 30, 2012 Consumer Loans [Member]	Jun. 30, 2011 Consumer Loans [Member]	Jun. 30, 2012 Consumer Loans [Member]	Jun. 30, 2011 Consumer Loans [Member]	Dec. 31, 2011 Consumer Loans [Member]	Jun. 30, 2012 Consumer Loans [Member] Pass [Member]	Dec. 31, 2011 Consumer Loans [Member] Pass [Member]	Jun. 30, 2012 Consumer Loans [Member] Watch [Member]	Dec. 31, 2011 Consumer Loans [Member] Watch [Member]	Jun. 30, 2012 Consumer Loans [Member] Substandard [Member]	Dec. 31, 2011 Consumer Loans [Member] Substandard [Member]	Jun. 30, 2012 Consumer Loans [Member] Doubtful [Member]	Dec. 31, 2011 Consumer Loans [Member] Doubtful [Member]	Jun. 30, 2012 All Other Loans [Member]	Jun. 30, 2011 All Other Loans [Member]	Jun. 30, 2012 All Other Loans [Member]	Jun. 30, 2011 All Other Loans [Member]	Dec. 31, 2011 All Other Loans [Member]	Jun. 30, 2012 All Other Loans [Member] Pass [Member]	Dec. 31, 2011 All Other Loans [Member] Pass [Member]	Jun. 30, 2012 All Other Loans [Member] Watch [Member]	Dec. 31, 2011 All Other Loans [Member] Watch [Member]	Jun. 30, 2012 All Other Loans [Member] Substandard [Member]	Dec. 31, 2011 All Other Loans [Member] Substandard [Member]	Jun. 30, 2012 All Other Loans [Member] Doubtful [Member]	Dec. 31, 2011 All Other Loans [Member] Doubtful [Member]	Jun. 30, 2012 Loans Secured by Real Estate [Member]	Jun. 30, 2011 Loans Secured by Real Estate [Member]	Jun. 30, 2012 Loans Secured by Real Estate [Member]	Jun. 30, 2011 Loans Secured by Real Estate [Member]	Dec. 31, 2011 Loans Secured by Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 844,875,000		$ 844,875,000			$ 859,732,000	$ 797,148	$ 809,177	$ 31,984	$ 31,945	$ 16,793	$ 18,952	$ 0	$ 0	$ 18,663,000		$ 18,663,000		$ 23,136,000	$ 15,060	$ 19,708	$ 2,162	$ 2,168	$ 1,441	$ 1,260	$ 0	$ 0	$ 78,274,000		$ 78,274,000		$ 72,586,000	$ 73,582	$ 67,637	$ 2,514	$ 2,496	$ 2,188	$ 2,452	$ 0	$ 0	$ 186,684,000		$ 186,684,000		$ 180,738,000	$ 185,236	$ 180,247	$ 435	$ 497	$ 2,582	$ 1,105	$ 0	$ 0	$ 31,067,000		$ 31,067,000		$ 19,847,000	$ 30,860	$ 19,638	$ 0	$ 0	$ 207	$ 208	$ 0	$ 0	$ 304,369,000		$ 304,369,000		$ 321,908,000	$ 274,571	$ 288,539	$ 24,026	$ 24,664	$ 5,086	$ 7,798	$ 0	$ 0	$ 56,436,000		$ 56,436,000		$ 63,182,000	$ 51,481	$ 58,133	$ 1,569	$ 1,840	$ 3,460	$ 3,284	$ 0	$ 0	$ 144,673,000		$ 144,673,000		$ 150,631,000	$ 141,679	$ 147,591	$ 1,278	$ 280	$ 1,815	$ 2,845	$ 0	$ 0	$ 15,839,000		$ 15,839,000		$ 16,274,000	$ 15,824	$ 16,271	$ 0	$ 0	$ 14	$ 0	$ 0	$ 0	$ 8,870,000		$ 8,870,000		$ 11,430,000	$ 8,855	$ 11,413	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 619,057,000		$ 619,057,000		$ 618,215,000
Minimum Balance Of Loans For Which Credit Quality Analysis Is Performed					100,000
Loans Receivable Aging Analysis [Abstract]
30 to 59 Days Past Due															0		0		0									204,000		204,000		377,000									636,000		636,000		1,079,000									0		0		0									617,000		617,000		399,000									272,000		272,000		0									258,000		258,000		950,000									89,000		89,000		94,000									0		0		0									1,457,000		1,457,000		1,855,000
60 to 89 Days Past Due															0		0		0									83,000		83,000		111,000									543,000		543,000		200,000									0		0		0									111,000		111,000		101,000									823,000		823,000		0									57,000		57,000		73,000									29,000		29,000		36,000									0		0		0									737,000		737,000		412,000
90 Days or More Past Due															0		0		0									70,000		70,000		737,000									967,000		967,000		1,033,000									0		0		0									346,000		346,000		228,000									58,000		58,000		673,000									248,000		248,000		585,000									15,000		15,000		7,000									0		0		0									1,383,000		1,383,000		1,998,000
Total Past Due															0		0		0									357,000		357,000		1,225,000									2,146,000		2,146,000		2,312,000									0		0		0									1,074,000		1,074,000		728,000									1,153,000		1,153,000		673,000									563,000		563,000		1,608,000									133,000		133,000		137,000									0		0		0									3,577,000		3,577,000		4,265,000
Current															18,663,000		18,663,000		23,136,000									77,927,000		77,927,000		71,360,000									186,107,000		186,107,000		179,537,000									31,067,000		31,067,000		19,846,000									302,609,000		302,609,000		320,273,000									55,357,000		55,357,000		62,584,000									144,209,000		144,209,000		149,108,000									15,705,000		15,705,000		16,134,000									8,855,000		8,855,000		11,413,000									616,373,000		616,373,000		614,152,000
Total Loans Greater than 90 Days Past Due and Still Accruing															0		0		0									0		0		0									0		0		0									0		0		0									0		0		0									0		0		0									0		0		0									0		0		0									0		0		0									0		0		0
Loans with a specific allowance [Abstract]
Recorded Balance						2,279,000,000									1,014,000		1,014,000		833,000									0		0		0									67,000		67,000		71,000									0		0		0									597,000		597,000		1,414,000									312,000		312,000		0									411,000		411,000		382,000									0		0		0									0		0		0									1,678,000		1,678,000		2,318,000
Unpaid Principal Balance						3,007,000,000									1,529,000		1,529,000		1,070,000									0		0		0									67,000		67,000		71,000									0		0		0									597,000		597,000		1,693,000									312,000		312,000		0									411,000		411,000		382,000									0		0		0									0		0		0									2,193,000		2,193,000		2,834,000
Specific Allowance						728,000,000									407,000		407,000		295,000									0		0		0									23,000		23,000		27,000									0		0		0									121,000		121,000		183,000									89,000		89,000		0									94,000		94,000		70,000									0		0		0									0		0		0									551,000		551,000		505,000
Loans without a specific allowance [Abstract]
Recorded Balance	4,518,000		4,518,000			4,740,000									0		0		0									206,000		206,000		532,000									1,535,000		1,535,000		1,641,000									0		0		0									1,840,000		1,840,000		1,226,000									553,000		553,000		673,000									369,000		369,000		660,000									15,000		15,000		8,000									0		0		0									3,581,000		3,581,000		3,399,000
Unpaid Principal Balance	5,120,000		5,120,000			5,554,000									0		0		0									206,000		206,000		532,000									1,862,000		1,862,000		1,818,000									0		0		0									1,879,000		1,879,000		1,256,000									553,000		553,000		673,000									589,000		589,000		1,255,000									31,000		31,000		20,000									0		0		0									3,947,000		3,947,000		3,606,000
Total Loans [Abstract]
Recorded Balance	6,919,000		6,919,000												1,014,000		1,014,000											206,000		206,000											1,602,000		1,602,000											0		0											2,437,000		2,437,000											865,000		865,000											780,000		780,000											15,000		15,000											0		0											5,259,000		5,259,000
Unpaid Principal Balance	8,036,000		8,036,000												1,529,000		1,529,000											206,000		206,000											1,929,000		1,929,000											0		0											2,476,000		2,476,000											865,000		865,000											1,000,000		1,000,000											31,000		31,000											0		0											6,140,000		6,140,000
Average recorded investment and interest income recognized [Abstract]
Average investment in impaired loans	6,937,000	10,477,000	6,935,000	10,699,000											1,014,000	1,430,000	1,014,000	1,422,000										206,000	535,000	206,000	536,000										1,621,000	2,320,000	1,632,000	2,331,000										0	0	0	0										2,437,000	4,074,000	2,349,000	4,483,000										864,000	752,000	883,000	756,000										780,000	1,366,000	834,000	1,171,000										15,000	0	17,000	0										0	0	0	0										5,278,000	8,359,000	5,201,000	8,772,000
Interest income recognized	10,000	1,000	21,000	7,000											0	0	0	0										0	0	0	0										0	0	0	0										0	0	0	0										7,000	1,000	14,000	7,000										0	0	0	0										3,000	0	7,000	0										0	0	0	0										0	0	0	0										7,000	1,000	14,000	7,000
Loans Receivable, Modifications, Still Accruing Interest																																									7,000		7,000																								389,000	398,000	389,000	398,000																							304,000		304,000
Balances of Nonaccrual Loans [Abstract]
Recorded balance of nonaccrual loans	6,219,000		6,219,000			6,723,000									1,014,000		1,014,000		833,000									206,000		206,000		532,000									1,595,000		1,595,000		1,712,000									0		0		0									2,048,000		2,048,000		2,245,000									865,000		865,000		673,000									476,000		476,000		720,000									15,000		15,000		8,000									0		0		0									4,863,000		4,863,000		5,322,000
Interest Lost on Nonaccrual Loans			130,000	255,000
Troubled Debt Restructuring [Abstract]
Troubled Debt Restructurings Balance	2,830,000		2,830,000			1,834,000									1,014,000		1,014,000		0																						471,000		471,000		393,000																						1,025,000		1,025,000		952,000																						320,000		320,000		489,000																																			2,510,000		2,510,000		1,345,000
Troubled Debt Restructuring, Allowance	559,000		559,000			140,000
Number of restructured notes															3		3																								1		1																												1																						1		1		1
Extension period of modified loan																																																																																																	18 months
Percentage of loans guaranteed by the Small Business Administration																																																																																																	75.00%
Recorded Balance of Troubled Debt Restructurings [Abstract]
Troubled Debt Restructurings Balance	2,830,000		2,830,000			1,834,000									1,014,000		1,014,000		0																						471,000		471,000		393,000																						1,025,000		1,025,000		952,000																						320,000		320,000		489,000																																			2,510,000		2,510,000		1,345,000
Financing Receivable Modifications Performing Recorded Investment	700,000		700,000			717,000																																			7,000		7,000		0																						389,000		389,000		395,000																						304,000		304,000		322,000																																			396,000		396,000		395,000
Subsequent Default, Number of Contracts	0		0			2
Subsequent Default, Troubled Debt Restructurings						$ 215,000,000