Allowance for Probable Loan Losses (Aging By Loan Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financing receivable recorded investment
Past due	$ 59,230	$ 68,273
Past due 90 days or Greater and Still Accruing	7,028	11,616
Loans, current	5,892,367	5,882,641
Total loans	5,951,597	5,950,914
30 to 59 Days
Financing receivable recorded investment
Past due	28,996	15,584
60 to 89 Days
Financing receivable recorded investment
Past due	6,822	5,219
90 Days or Greater
Financing receivable recorded investment
Past due	23,412	47,470
Commercial
Financing receivable recorded investment
Past due	20,726	32,916
Past due 90 days or Greater and Still Accruing	2,549	2,566
Loans, current	921,226	933,936
Total loans	941,952	966,852
Commercial \| 30 to 59 Days
Financing receivable recorded investment
Past due	8,830	3,361
Commercial \| 60 to 89 Days
Financing receivable recorded investment
Past due	1,078	940
Commercial \| 90 Days or Greater
Financing receivable recorded investment
Past due	10,818	28,615
Commercial Real Estate: Other Construction and Land Development
Financing receivable recorded investment
Past due	4,857	3,988
Past due 90 days or Greater and Still Accruing	143
Loans, current	1,681,254	1,645,839
Total loans	1,686,111	1,649,827
Commercial Real Estate: Other Construction and Land Development \| 30 to 59 Days
Financing receivable recorded investment
Past due	2,404	193
Commercial Real Estate: Other Construction and Land Development \| 60 to 89 Days
Financing receivable recorded investment
Past due	199	293
Commercial Real Estate: Other Construction and Land Development \| 90 Days or Greater
Financing receivable recorded investment
Past due	2,254	3,502
Commercial Real Estate: Farmland & Commercial
Financing receivable recorded investment
Past due	16,852	12,304
Past due 90 days or Greater and Still Accruing	189	3,373
Loans, current	1,936,919	1,983,144
Total loans	1,953,771	1,995,448
Commercial Real Estate: Farmland & Commercial \| 30 to 59 Days
Financing receivable recorded investment
Past due	9,269	2,684
Commercial Real Estate: Farmland & Commercial \| 60 to 89 Days
Financing receivable recorded investment
Past due	2,940	1,328
Commercial Real Estate: Farmland & Commercial \| 90 Days or Greater
Financing receivable recorded investment
Past due	4,643	8,292
Commercial Real Estate: Multifamily
Financing receivable recorded investment
Past due	1,686	1,317
Past due 90 days or Greater and Still Accruing		49
Loans, current	137,740	138,131
Total loans	139,426	139,448
Commercial Real Estate: Multifamily \| 30 to 59 Days
Financing receivable recorded investment
Past due	721	49
Commercial Real Estate: Multifamily \| 60 to 89 Days
Financing receivable recorded investment
Past due	375	442
Commercial Real Estate: Multifamily \| 90 Days or Greater
Financing receivable recorded investment
Past due	590	826
Residential First Lien
Financing receivable recorded investment
Past due	9,297	11,139
Past due 90 days or Greater and Still Accruing	3,135	4,093
Loans, current	406,579	399,105
Total loans	415,876	410,244
Residential First Lien \| 30 to 59 Days
Financing receivable recorded investment
Past due	4,349	5,299
Residential First Lien \| 60 to 89 Days
Financing receivable recorded investment
Past due	1,401	1,545
Residential First Lien \| 90 Days or Greater
Financing receivable recorded investment
Past due	3,547	4,295
Residential Junior Lien
Financing receivable recorded investment
Past due	1,460	1,772
Past due 90 days or Greater and Still Accruing	325	640
Loans, current	579,973	550,566
Total loans	581,433	552,338
Residential Junior Lien \| 30 to 59 Days
Financing receivable recorded investment
Past due	710	713
Residential Junior Lien \| 60 to 89 Days
Financing receivable recorded investment
Past due	256	413
Residential Junior Lien \| 90 Days or Greater
Financing receivable recorded investment
Past due	494	646
Consumer
Financing receivable recorded investment
Past due	1,817	1,308
Past due 90 days or Greater and Still Accruing	381	453
Loans, current	54,300	56,436
Total loans	56,117	57,744
Consumer \| 30 to 59 Days
Financing receivable recorded investment
Past due	1,246	646
Consumer \| 60 to 89 Days
Financing receivable recorded investment
Past due	190	175
Consumer \| 90 Days or Greater
Financing receivable recorded investment
Past due	381	487
Foreign
Financing receivable recorded investment
Past due	2,535	3,529
Past due 90 days or Greater and Still Accruing	306	442
Loans, current	174,376	175,484
Total loans	176,911	179,013
Foreign \| 30 to 59 Days
Financing receivable recorded investment
Past due	1,467	2,639
Foreign \| 60 to 89 Days
Financing receivable recorded investment
Past due	383	83
Foreign \| 90 Days or Greater
Financing receivable recorded investment
Past due	$ 685	$ 807

Recorded investment in financing receivables that are 90 days or more past due and still accruing.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5111-111524

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Financing receivables that are current.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953401-111524

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5074-111524

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