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Allowance for Probable Loan Losses (Portfolio Credit Quality By Loan Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Loan portfolio by credit quality indicator
Portfolio, total	$ 6,842,701	$ 6,561,289
Pass
Loan portfolio by credit quality indicator
Portfolio, total	6,508,353	6,126,933
Special Review
Loan portfolio by credit quality indicator
Portfolio, total	56,177	64,135
Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	46,397	92,976
Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	208,067	253,345
Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	23,707	23,900
Commercial
Loan portfolio by credit quality indicator
Portfolio, total	1,202,743	1,128,969
Commercial | Pass
Loan portfolio by credit quality indicator
Portfolio, total	1,141,456	998,625
Commercial | Special Review
Loan portfolio by credit quality indicator
Portfolio, total	19	441
Commercial | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	1,694	44,544
Commercial | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	51,101	76,180
Commercial | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	8,473	9,179
Commercial Real Estate:Other Construction and Land Development
Loan portfolio by credit quality indicator
Portfolio, total	2,010,198	1,886,231
Commercial Real Estate:Other Construction and Land Development | Pass
Loan portfolio by credit quality indicator
Portfolio, total	1,942,982	1,817,098
Commercial Real Estate:Other Construction and Land Development | Special Review
Loan portfolio by credit quality indicator
Portfolio, total		1,648
Commercial Real Estate:Other Construction and Land Development | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	9,310	9,055
Commercial Real Estate:Other Construction and Land Development | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	55,982	56,338
Commercial Real Estate:Other Construction and Land Development | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	1,924	2,092
Commercial Real Estate: Farmland and Commercial
Loan portfolio by credit quality indicator
Portfolio, total	2,027,996	1,949,898
Commercial Real Estate: Farmland and Commercial | Pass
Loan portfolio by credit quality indicator
Portfolio, total	1,834,448	1,726,711
Commercial Real Estate: Farmland and Commercial | Special Review
Loan portfolio by credit quality indicator
Portfolio, total	56,158	62,046
Commercial Real Estate: Farmland and Commercial | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	34,394	38,373
Commercial Real Estate: Farmland and Commercial | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	98,836	119,259
Commercial Real Estate: Farmland and Commercial | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	4,160	3,509
Commercial Real Estate: Multifamily
Loan portfolio by credit quality indicator
Portfolio, total	221,431	226,257
Commercial Real Estate: Multifamily | Pass
Loan portfolio by credit quality indicator
Portfolio, total	220,023	224,823
Commercial Real Estate: Multifamily | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	903	927
Commercial Real Estate: Multifamily | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	505	507
Residential First Lien
Loan portfolio by credit quality indicator
Portfolio, total	460,178	445,800
Residential First Lien | Pass
Loan portfolio by credit quality indicator
Portfolio, total	452,493	438,773
Residential First Lien | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	143	142
Residential First Lien | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	1,245	641
Residential First Lien | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	6,297	6,244
Residential Junior Lien
Loan portfolio by credit quality indicator
Portfolio, total	725,264	727,301
Residential Junior Lien | Pass
Loan portfolio by credit quality indicator
Portfolio, total	723,385	725,538
Residential Junior Lien | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	856	862
Residential Junior Lien | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	1,023	901
Consumer
Loan portfolio by credit quality indicator
Portfolio, total	46,713	46,316
Consumer | Pass
Loan portfolio by credit quality indicator
Portfolio, total	45,667	45,141
Consumer | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	1,046	1,175
Foreign
Loan portfolio by credit quality indicator
Portfolio, total	148,178	150,517
Foreign | Pass
Loan portfolio by credit quality indicator
Portfolio, total	147,899	150,224
Foreign | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	$ 279	$ 293

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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.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

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-Paragraph 4
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