Allowance for Probable Loan Losses (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Interest Recognized
Total trouble debt restructuring	$ 15,432	$ 15,653
Period of charge off for past due unsecured commercial loans	90 days
Class of financing receivable
Recorded investment:
Total impaired loans with related allowance	33,262	31,765
Total impaired loans with no related allowance	40,488	44,406
Unpaid principal balance:
Total impaired loans with an allowance recorded	33,782	32,232
Total impaired loans with no related allowance recorded	41,604	46,262
Related Allowance	13,724	12,221
Average recorded investment:
Total impaired loans with an allowance recorded	32,034	33,286
Total impaired loans with no related allowance recorded	41,388	43,202
Interest Recognized
Total impaired loans with an allowance recorded	23	92
Total impaired loans with no related allowance recorded	107	444
Commercial
Interest Recognized
Total trouble debt restructuring	2,464	2,500
Commercial \| Class of financing receivable
Recorded investment:
Total impaired loans with related allowance	21,865	19,944
Total impaired loans with no related allowance	19,390	20,231
Unpaid principal balance:
Total impaired loans with an allowance recorded	21,979	20,026
Total impaired loans with no related allowance recorded	19,410	20,260
Related Allowance	10,790	9,112
Average recorded investment:
Total impaired loans with an allowance recorded	20,623	19,313
Total impaired loans with no related allowance recorded	19,737	18,563
Interest Recognized
Total impaired loans with no related allowance recorded	1	4
Commercial real estate: other construction and land development
Interest Recognized
Total trouble debt restructuring	2,254	2,254
Commercial real estate: other construction and land development \| Class of financing receivable
Recorded investment:
Total impaired loans with related allowance	6,323	6,714
Total impaired loans with no related allowance	3,609	4,162
Unpaid principal balance:
Total impaired loans with an allowance recorded	6,546	6,949
Total impaired loans with no related allowance recorded	3,708	4,270
Related Allowance	1,956	1,890
Average recorded investment:
Total impaired loans with an allowance recorded	6,323	7,183
Total impaired loans with no related allowance recorded	3,610	4,882
Interest Recognized
Total impaired loans with no related allowance recorded	19	74
Commercial real estate: farmland and commercial
Interest Recognized
Total trouble debt restructuring	2,853	2,861
Commercial real estate: farmland and commercial \| Class of financing receivable
Recorded investment:
Total impaired loans with related allowance	5,074	5,107
Total impaired loans with no related allowance	8,393	9,059
Unpaid principal balance:
Total impaired loans with an allowance recorded	5,257	5,257
Total impaired loans with no related allowance recorded	9,315	10,562
Related Allowance	978	1,219
Average recorded investment:
Total impaired loans with an allowance recorded	5,088	6,790
Total impaired loans with no related allowance recorded	8,868	8,664
Interest Recognized
Total impaired loans with an allowance recorded	23	92
Commercial real estate: multifamily
Interest Recognized
Total trouble debt restructuring	21
Commercial real estate: multifamily \| Class of financing receivable
Recorded investment:
Total impaired loans with no related allowance	841	835
Unpaid principal balance:
Total impaired loans with no related allowance recorded	841	835
Average recorded investment:
Total impaired loans with no related allowance recorded	846	363
Residential: first lien
Interest Recognized
Total trouble debt restructuring	4,921	5,313
Residential: first lien \| Class of financing receivable
Recorded investment:
Total impaired loans with no related allowance	5,293	5,840
Unpaid principal balance:
Total impaired loans with no related allowance recorded	5,345	6,034
Average recorded investment:
Total impaired loans with no related allowance recorded	5,357	6,293
Interest Recognized
Total impaired loans with no related allowance recorded	62	273
Residential: junior lien
Interest Recognized
Total trouble debt restructuring	1,347	1,371
Residential: junior lien \| Class of financing receivable
Recorded investment:
Total impaired loans with no related allowance	1,369	2,895
Unpaid principal balance:
Total impaired loans with no related allowance recorded	1,390	2,915
Average recorded investment:
Total impaired loans with no related allowance recorded	1,374	3,035
Interest Recognized
Total impaired loans with no related allowance recorded	20	90
Consumer Loan
Interest Recognized
Total trouble debt restructuring	1,167	1,354
Consumer Loan \| Class of financing receivable
Recorded investment:
Total impaired loans with no related allowance	1,188	1,384
Unpaid principal balance:
Total impaired loans with no related allowance recorded	1,190	1,386
Average recorded investment:
Total impaired loans with no related allowance recorded	1,189	1,402
Interest Recognized
Total impaired loans with no related allowance recorded	1	3
Foreign
Interest Recognized
Total trouble debt restructuring	405
Foreign \| Class of financing receivable
Recorded investment:
Total impaired loans with no related allowance	405
Unpaid principal balance:
Total impaired loans with no related allowance recorded	405
Average recorded investment:
Total impaired loans with no related allowance recorded	407
Interest Recognized
Total impaired loans with no related allowance recorded	$ 4

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 40

-Section 50

-Paragraph 4

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-SubTopic 10

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