Loans (Details 7) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Impaired loans with no recorded reserve:
Recorded Investment	$ 35,556	$ 49,193
Unpaid Principal Balance	35,556	49,193
Average Recorded Investment	35,556	55,748
Interest Income Recognized	384	2,082
Impaired loans with recorded reserve:
Recorded Investment	8,109	17,411
Unpaid Principal Balance	8,109	17,411
Related Allowance	2,664	3,841	4,600
Average Recorded Investment	8,109	23,574
Interest Income Recognized	34	755
Total impaired loans Recorded Investment	43,665	66,604	82,200
Total impaired loans Unpaid Principal Balance	43,665	66,604
Total impaired loans Related Allowance	2,664	3,841	4,600
Total impaired loans Average Recorded Investment	43,665	79,322
Total impaired loans Interest Income Recognized	418	2,837
One-to-four family mortgages [Member]
Impaired loans with no recorded reserve:
Recorded Investment	1,239	1,759
Unpaid Principal Balance	1,239	1,759
Average Recorded Investment	1,239	5,279
Interest Income Recognized	8	107
Impaired loans with recorded reserve:
Recorded Investment	2,338	2,836
Unpaid Principal Balance	2,238	2,836
Related Allowance	792	754
Average Recorded Investment	2,338	3,135
Interest Income Recognized	10	145
Total impaired loans Related Allowance	792	754
Home equity line of credit [Member]
Impaired loans with no recorded reserve:
Recorded Investment	545	1,169
Unpaid Principal Balance	545	1,169
Average Recorded Investment	545	869
Interest Income Recognized	3	50
Impaired loans with recorded reserve:
Recorded Investment	343	68
Unpaid Principal Balance	343	68
Related Allowance	144	76
Average Recorded Investment	343	162
Interest Income Recognized	2	3
Total impaired loans Related Allowance	144	76
Junior liens [Member]
Impaired loans with no recorded reserve:
Recorded Investment	370
Unpaid Principal Balance	370
Average Recorded Investment	370	281
Interest Income Recognized	2	3
Impaired loans with recorded reserve:
Recorded Investment	85	468
Unpaid Principal Balance	85	468
Related Allowance	70	188
Average Recorded Investment	85	365
Interest Income Recognized	1	38
Total impaired loans Related Allowance	70	188
Multi-family [Member]
Impaired loans with no recorded reserve:
Recorded Investment	1,866	4,077
Unpaid Principal Balance	1,866	4,077
Average Recorded Investment	1,866	3,626
Interest Income Recognized	16	219
Impaired loans with recorded reserve:
Recorded Investment		38
Unpaid Principal Balance		38
Related Allowance		38
Average Recorded Investment		2,640
Interest Income Recognized		4
Total impaired loans Related Allowance		38
Construction [Member]
Impaired loans with no recorded reserve:
Recorded Investment	4,112	4,848
Unpaid Principal Balance	4,112	4,848
Average Recorded Investment	4,112	3,133
Interest Income Recognized	18	174
Impaired loans with recorded reserve:
Recorded Investment
Unpaid Principal Balance
Related Allowance
Average Recorded Investment		1,095
Interest Income Recognized
Total impaired loans Related Allowance
Land [Member]
Impaired loans with no recorded reserve:
Recorded Investment	15,148	20,279
Unpaid Principal Balance	15,148	20,279
Average Recorded Investment	15,148	19,857
Interest Income Recognized	181	504
Impaired loans with recorded reserve:
Recorded Investment	3,571	3,570
Unpaid Principal Balance	3,571	3,570
Related Allowance	945	932
Average Recorded Investment	3,571	4,848
Interest Income Recognized	12	213
Total impaired loans Related Allowance	945	932
Farmland [Member]
Impaired loans with no recorded reserve:
Recorded Investment	4,320,000	5,701
Unpaid Principal Balance	4,320,000	5,701
Average Recorded Investment	4,320,000	5,701
Interest Income Recognized	76,000	202
Impaired loans with recorded reserve:
Recorded Investment	452	1,372
Unpaid Principal Balance	452	1,372
Related Allowance	18	184
Average Recorded Investment	452	1,372
Interest Income Recognized	1	92
Total impaired loans Related Allowance	18	184
Non-residential real estate [Member]
Impaired loans with no recorded reserve:
Recorded Investment	5,390	9,662
Unpaid Principal Balance	5,390	9,662
Average Recorded Investment	5,390	14,235
Interest Income Recognized	27	653
Impaired loans with recorded reserve:
Recorded Investment	181	4,359
Unpaid Principal Balance	181	4,359
Related Allowance	117	1,240
Average Recorded Investment	181	5,206
Interest Income Recognized	2	231
Total impaired loans Related Allowance	117	1,240
Consumer loans [Member]
Impaired loans with no recorded reserve:
Recorded Investment	49	81
Unpaid Principal Balance	49	81
Average Recorded Investment	49	66
Interest Income Recognized	2	5
Impaired loans with recorded reserve:
Recorded Investment	223	475
Unpaid Principal Balance	223	475
Related Allowance	56	121
Average Recorded Investment	223	281
Interest Income Recognized		1
Total impaired loans Related Allowance	56	121
Commercial loans [Member]
Impaired loans with no recorded reserve:
Recorded Investment	2,517	1,617
Unpaid Principal Balance	2,517	1,617
Average Recorded Investment	2,517	2,701
Interest Income Recognized	51	165
Impaired loans with recorded reserve:
Recorded Investment	916	4,225
Unpaid Principal Balance	916	4,225
Related Allowance	522	308
Average Recorded Investment	916	4,470
Interest Income Recognized	6	28
Total impaired loans Related Allowance	$ 522	$ 308