Allowance for Probable Loan Losses (Details 5) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financing receivable recorded investment
Past due 30-59 days	$ 24,390	$ 17,261
Past due 60-89 days	9,270	12,215
Past due 90 days or greater	55,964	67,770
Past due 90 days or greater and still accruing	7,008	9,988
Past due, total	89,624	97,246
Loans, current	5,689,118	5,581,999
Total loans	5,778,742	5,679,245
Commercial
Financing receivable recorded investment
Past due 30-59 days	8,388	4,103
Past due 60-89 days	2,950	2,665
Past due 90 days or greater	35,685	40,665
Past due 90 days or greater and still accruing	595	2,890
Past due, total	47,023	47,433
Loans, current	1,046,260	1,042,053
Total loans	1,093,283	1,089,486
Commercial real estate: other construction and land development
Financing receivable recorded investment
Past due 30-59 days	1,222	596
Past due 60-89 days	580	10
Past due 90 days or greater	7,432	8,707
Past due 90 days or greater and still accruing	51	439
Past due, total	9,234	9,313
Loans, current	1,513,337	1,405,664
Total loans	1,522,571	1,414,977
Commercial real estate: farmland and commercial
Financing receivable recorded investment
Past due 30-59 days	8,229	2,905
Past due 60-89 days	3,446	7,131
Past due 90 days or greater	6,267	10,724
Past due 90 days or greater and still accruing	866	1,711
Past due, total	17,962	20,760
Loans, current	1,878,031	1,880,639
Total loans	1,895,993	1,901,399
Commercial real estate: multifamily
Financing receivable recorded investment
Past due 30-59 days	204	351
Past due 90 days or greater	976	856
Past due 90 days or greater and still accruing	156	21
Past due, total	1,180	1,207
Loans, current	104,066	115,492
Total loans	105,246	116,699
Residential: first lien
Financing receivable recorded investment
Past due 30-59 days	3,382	5,895
Past due 60-89 days	1,635	1,864
Past due 90 days or greater	4,460	4,267
Past due 90 days or greater and still accruing	4,214	3,901
Past due, total	9,477	12,026
Loans, current	414,331	410,000
Total loans	423,808	422,026
Residential: junior lien
Financing receivable recorded investment
Past due 30-59 days	989	899
Past due 60-89 days	173	231
Past due 90 days or greater	538	1,931
Past due 90 days or greater and still accruing	538	431
Past due, total	1,700	3,061
Loans, current	491,430	485,239
Total loans	493,130	488,300
Consumer Loan
Financing receivable recorded investment
Past due 30-59 days	560	896
Past due 60-89 days	242	216
Past due 90 days or greater	337	507
Past due 90 days or greater and still accruing	319	482
Past due, total	1,139	1,619
Loans, current	58,115	59,518
Total loans	59,254	61,137
Foreign
Financing receivable recorded investment
Past due 30-59 days	1,416	1,616
Past due 60-89 days	224	98
Past due 90 days or greater	269	113
Past due 90 days or greater and still accruing	269	113
Past due, total	1,909	1,827
Loans, current	183,548	183,394
Total loans	$ 185,457	$ 185,221

Financing receivables that are less than 60 days past due but more than 29 days past due.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7A

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

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-Name Accounting Standards Codification

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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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