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Allowance for Probable Loan Losses (Impairment By Loan Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	$ 37,723	$ 60,448
Loans Individually Evaluated for Impairment, Allowance	1,078	2,206
Loans Collectively Evaluated for Impairment, Recorded Investment	5,913,874	5,890,466
Loans Collectively Evaluated for Impairment, Allowance	60,955	64,782
Commercial
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	13,151	30,946
Loans Individually Evaluated for Impairment, Allowance	831	1,704
Loans Collectively Evaluated for Impairment, Recorded Investment	928,801	935,905
Loans Collectively Evaluated for Impairment, Allowance	25,151	19,727
Commercial Real Estate: Other Construction and Land Development
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	4,150	6,221
Loans Individually Evaluated for Impairment, Allowance	116	100
Loans Collectively Evaluated for Impairment, Recorded Investment	1,681,961	1,643,606
Loans Collectively Evaluated for Impairment, Allowance	10,993	13,820
Commercial Real Estate: Farmland & Commercial
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	10,243	13,806
Loans Individually Evaluated for Impairment, Allowance	131	202
Loans Collectively Evaluated for Impairment, Recorded Investment	1,943,528	1,981,643
Loans Collectively Evaluated for Impairment, Allowance	16,811	19,567
Commercial Real Estate: Multifamily
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	590	777
Loans Individually Evaluated for Impairment, Allowance		200
Loans Collectively Evaluated for Impairment, Recorded Investment	138,836	138,671
Loans Collectively Evaluated for Impairment, Allowance	855	1,048
Residential First Lien
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	6,683	5,699
Loans Collectively Evaluated for Impairment, Recorded Investment	409,193	404,545
Loans Collectively Evaluated for Impairment, Allowance	2,277	3,509
Residential Junior Lien
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	1,021	950
Loans Collectively Evaluated for Impairment, Recorded Investment	580,412	551,388
Loans Collectively Evaluated for Impairment, Allowance	3,400	5,321
Consumer
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	1,132	1,297
Loans Collectively Evaluated for Impairment, Recorded Investment	54,985	56,447
Loans Collectively Evaluated for Impairment, Allowance	532	638
Foreign
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	753	752
Loans Collectively Evaluated for Impairment, Recorded Investment	176,158	178,261
Loans Collectively Evaluated for Impairment, Allowance	$ 936	$ 1,152

X

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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+ References

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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- Definition

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+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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