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Allowance for Probable Loan Losses (Portfolio Credit Quality By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loan portfolio by credit quality indicator
Portfolio, total	$ 6,707,343	$ 6,561,289
Pass
Loan portfolio by credit quality indicator
Portfolio, total	6,316,834	6,126,933
Special Review
Loan portfolio by credit quality indicator
Portfolio, total	63,671	64,135
Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	52,626	92,976
Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	218,163	253,345
Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	56,049	23,900
Commercial
Loan portfolio by credit quality indicator
Portfolio, total	1,213,539	1,128,969
Commercial | Pass
Loan portfolio by credit quality indicator
Portfolio, total	1,130,988	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	3,061	44,544
Commercial | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	60,863	76,180
Commercial | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	18,608	9,179
Commercial Real Estate:Other Construction and Land Development
Loan portfolio by credit quality indicator
Portfolio, total	1,934,346	1,886,231
Commercial Real Estate:Other Construction and Land Development | Pass
Loan portfolio by credit quality indicator
Portfolio, total	1,865,359	1,817,098
Commercial Real Estate:Other Construction and Land Development | Special Review
Loan portfolio by credit quality indicator
Portfolio, total	1,640	1,648
Commercial Real Estate:Other Construction and Land Development | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	9,284	9,055
Commercial Real Estate:Other Construction and Land Development | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	56,004	56,338
Commercial Real Estate:Other Construction and Land Development | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	2,059	2,092
Commercial Real Estate: Farmland and Commercial
Loan portfolio by credit quality indicator
Portfolio, total	1,896,658	1,949,898
Commercial Real Estate: Farmland and Commercial | Pass
Loan portfolio by credit quality indicator
Portfolio, total	1,669,873	1,726,711
Commercial Real Estate: Farmland and Commercial | Special Review
Loan portfolio by credit quality indicator
Portfolio, total	62,012	62,046
Commercial Real Estate: Farmland and Commercial | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	39,269	38,373
Commercial Real Estate: Farmland and Commercial | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	99,113	119,259
Commercial Real Estate: Farmland and Commercial | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	26,391	3,509
Commercial Real Estate: Multifamily
Loan portfolio by credit quality indicator
Portfolio, total	294,112	226,257
Commercial Real Estate: Multifamily | Pass
Loan portfolio by credit quality indicator
Portfolio, total	292,687	224,823
Commercial Real Estate: Multifamily | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	918	927
Commercial Real Estate: Multifamily | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	507	507
Residential First Lien
Loan portfolio by credit quality indicator
Portfolio, total	456,914	445,800
Residential First Lien | Pass
Loan portfolio by credit quality indicator
Portfolio, total	449,291	438,773
Residential First Lien | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	142	142
Residential First Lien | Watch List - Substandard
Loan portfolio by credit quality indicator
Portfolio, total	1,265	641
Residential First Lien | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	6,216	6,244
Residential Junior Lien
Loan portfolio by credit quality indicator
Portfolio, total	721,112	727,301
Residential Junior Lien | Pass
Loan portfolio by credit quality indicator
Portfolio, total	719,334	725,538
Residential Junior Lien | Watch List - Pass
Loan portfolio by credit quality indicator
Portfolio, total	870	862
Residential Junior Lien | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	908	901
Consumer
Loan portfolio by credit quality indicator
Portfolio, total	46,073	46,316
Consumer | Pass
Loan portfolio by credit quality indicator
Portfolio, total	44,999	45,141
Consumer | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	1,074	1,175
Foreign
Loan portfolio by credit quality indicator
Portfolio, total	144,589	150,517
Foreign | Pass
Loan portfolio by credit quality indicator
Portfolio, total	144,303	150,224
Foreign | Watch - List Impaired
Loan portfolio by credit quality indicator
Portfolio, total	$ 286	$ 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=82891408&loc=d3e4428-111522

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-Paragraph 4
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