International Bancshares (IBOC) 10-Q 5 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 29, 2014
Document and Entity Information	'	'
Entity Registrant Name	'INTERNATIONAL BANCSHARES CORP	'
Entity Central Index Key	'0000315709	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	66,967,298
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'

Consolidated_Statements_of_Con

Consolidated Statements of Condition (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets	'	'
Cash and cash equivalents	$351,287	$274,785
Investment securities:	'	'
Held-to-maturity (Market value of $2,400 on March 31, 2014 and $2,400 on December 31, 2013)	2,400	2,400
Available-for-sale (Amortized cost of $5,259,440 on March 31, 2014 and $5,372,594 on December 31, 2013)	5,222,557	5,304,579
Total investment securities	5,224,957	5,306,979
Loans	5,286,500	5,199,235
Less allowance for probable loan losses	-70,408	-70,161
Net loans	5,216,092	5,129,074
Bank premises and equipment, net	510,583	504,842
Accrued interest receivable	28,309	30,654
Other investments	382,072	388,563
Identified intangible assets, net	2,205	3,186
Goodwill	282,532	282,532
Other assets	146,148	158,862
Total assets	12,144,185	12,079,477
Deposits:	'	'
Demand - non-interest bearing	2,829,995	2,666,510
Savings and interest bearing demand	2,966,062	2,925,612
Time	2,640,186	2,651,303
Total deposits	8,436,243	8,243,425
Securities sold under repurchase agreements	837,170	957,381
Other borrowed funds	1,148,403	1,223,950
Junior subordinated deferrable interest debentures	180,416	190,726
Other liabilities	76,037	39,587
Total liabilities	10,678,269	10,655,069
Shareholders' equity:	'	'
Common shares of $1.00 par value. Authorized 275,000,000 shares; issued 95,751,991 shares on March 31, 2014 and 95,743,592 shares on December 31, 2013	95,752	95,744
Surplus	164,220	163,947
Retained earnings	1,493,904	1,467,000
Accumulated other comprehensive loss (including $(5,567) and $(5,646) of comprehensive loss related to other-than-temporary impairment for non-credit related issues)	-23,696	-43,774
Total shareholders' equity before treasury stock	1,730,180	1,682,917
Less cost of shares in treasury, 28,787,389 shares on March 31, 2014 and 28,537,180 December 31, 2013	-264,264	-258,509
Total shareholders' equity	1,465,916	1,424,408
Total liabilities and shareholders' equity	$12,144,185	$12,079,477

Consolidated_Statements_of_Con1

Consolidated Statements of Condition (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Consolidated Statements of Condition	'	'
Held to maturity, Market value (in dollars)	$2,400	$2,400
Available for sale, Amortized cost (in dollars)	5,259,440	5,372,594
Common shares, par value (in dollars per share)	$1	$1
Common shares, Authorized shares	275,000,000	275,000,000
Common shares, issued shares	95,751,991	95,743,592
Accumulated other comprehensive income, comprehensive loss related to other-than-temporary impairment for non-credit related issues (in dollars)	($5,567)	($5,646)
Treasury, shares	28,787,389	28,537,180

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Interest income:	'	'
Loans, including fees	$67,872	$63,534
Investment securities:	'	'
Taxable	26,179	20,519
Tax-exempt	3,523	3,036
Other interest income	63	21
Total interest income	97,637	87,110
Interest expense:	'	'
Savings deposits	871	1,011
Time deposits	3,120	4,445
Securities sold under repurchase agreements	6,236	7,568
Other borrowings	556	290
Junior subordinated interest deferrable debentures	1,090	1,164
Total interest expense	11,873	14,478
Net interest income	85,764	72,632
Provision for probable loan losses	2,078	7,419
Net interest income after provision for probable loan losses	83,686	65,213
Non-interest income:	'	'
Service charges on deposit accounts	22,062	23,830
Other service charges, commissions and fees	'	'
Banking	10,820	9,983
Non-banking	1,899	1,061
Investment securities transactions, net	8,108	9,601
Other investments, net	9,058	6,997
Other income	6,239	1,780
Total non-interest income	58,186	53,252
Non-interest expense:	'	'
Employee compensation and benefits	30,245	30,211
Occupancy	7,008	7,812
Depreciation of bank premises and equipment	6,092	6,625
Professional fees	3,612	3,723
Deposit insurance assessments	1,439	1,616
Net expense, other real estate owned	929	1,789
Amortization of identified intangible assets	981	1,137
Advertising	1,830	1,846
Early termination fee - securities sold under repurchase agreements	11,000	9,885
Impairment charges (Total other-than-temporary impairment charges, $32 net of $(122), and $968, net of $658, included in other comprehensive loss)	90	310
Other	14,470	15,907
Total non-interest expense	77,696	80,861
Income before income taxes	64,176	37,604
Provision for income taxes	20,530	9,535
Net income	$43,646	$28,069
Basic earnings per common share:	'	'
Weighted average number of shares outstanding: (in shares)	67,130,971	67,187,583
Net income (in dollars per share)	$0.65	$0.42
Fully diluted earnings per common share:	'	'
Weighted average number of shares outstanding: (in shares)	67,272,299	67,279,981
Net income (in dollars per share)	$0.65	$0.42

Consolidated_Statements_of_Inc1

Consolidated Statements of Income (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Consolidated Statements of Income	'	'
Impairment charges, other-than-temporary impairment charges	$32	$968
Impairment charges, other comprehensive (loss) income	($122)	$658

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Consolidated Statements of Comprehensive Income	'	'
Net income	$43,646	$28,069
Other comprehensive income, net of tax:	'	'
Net unrealized holding gains (losses) on securities available for sale arising during period (tax effects of $13,616 and $(5,143))	25,289	-9,552
Reclassification adjustment for gains on securities available for sale included in net income (tax effects of $(2,838) and $(3,360))	-5,270	-6,241
Reclassification adjustment for impairment charges on available for sale securities included in net income (tax effects of $31 and $108)	59	202
Other comprehensive income (loss), net of tax	20,078	-15,591
Comprehensive income	$63,724	$12,478

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Consolidated Statements of Comprehensive Income	'	'
Net unrealized holding gains (losses) on securities available for sale arising during period, tax effects	$13,616	($5,143)
Reclassification adjustment for gains on securities available for sale included in net income, tax effects	-2,838	-3,360
Reclassification adjustment for impairment charges on available for sale securities included in net income, tax effects	$31	$108

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating activities:	'	'
Net income	$43,646	$28,069
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Provision for probable loan losses	2,078	7,419
Specific reserve, other real estate owned	138	-70
Depreciation of bank premises and equipment	6,092	6,625
Gain on sale of bank premises and equipment	-2,956	-21
Gain on sale of other real estate owned	-233	-39
Accretion of investment securities discounts	-1,274	-894
Amortization of investment securities premiums	6,765	11,204
Investment securities transactions, net	-8,108	-9,601
Impairment charges on available-for-sale investment securities	90	310
Amortization of identified intangible assets	981	1,137
Stock based compensation expense	161	114
Earnings from affiliates and other investments	-3,109	-4,702
Deferred tax benefit	-1,666	-2,098
Decrease in accrued interest receivable	2,345	2,650
Net (increase) decrease in other assets	-365	8,926
Net increase in other liabilities	16,630	4,404
Net cash provided by operating activities	61,215	53,433
Investing activities:	'	'
Proceeds from sales and calls of available for sale securities	258,277	178,124
Purchases of available for sale securities	-310,921	-217,214
Principal collected on mortgage-backed securities	171,405	396,105
Net increase in loans	-88,610	-59,937
Purchases of other investments	-681	-512
Distributions from other investments	10,281	9,878
Purchases of bank premises and equipment	-14,436	-6,166
Proceeds from sales of other real estate owned	5,559	4,410
Proceeds from sale of bank premises and equipment	3,298	21
Net cash provided by investing activities	34,172	304,709
Financing activities:	'	'
Net increase in non-interest bearing demand deposits	163,485	146,577
Net increase in savings and interest bearing demand deposits	40,450	1,413
Net decrease in time deposits	-11,117	-118,660
Net decrease in securities sold under repurchase agreements	-120,211	-74,092
Net decrease in other borrowed funds	-75,547	-361,534
Redemption of long-term debt	-10,310	'
Purchases of treasury stock	-5,755	'
Proceeds from stock transactions	120	13
Net cash used in financing activities	-18,885	-406,283
Increase (decrease) in cash and cash equivalents	76,502	-48,141
Cash and cash equivalents at beginning of period	274,785	283,100
Cash and cash equivalents at end of period	351,287	234,959
Supplemental cash flow information:	'	'
Interest paid	12,594	15,590
Income taxes paid	5,652	5,000
Non-cash investing and financing activities:	'	'
Dividends declared, not yet paid	16,741	13,439
Net transfer from loans to other real estate owned	486	5,788
Purchases of available-for-sale securities not yet settled	$3,079	$37,545

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2014
Basis of Presentation	'
Basis of Presentation	'
	Note 1 - Basis of Presentation
	The accounting and reporting policies of International Bancshares Corporation (“Corporation”) and Subsidiaries (the Corporation and Subsidiaries collectively referred to herein as the “Company”) conform to accounting principles generally accepted in the United States of America and to general practices within the banking industry.  The consolidated financial statements include the accounts of the Corporation and its wholly-owned subsidiaries, International Bank of Commerce, Laredo (“IBC”), Commerce Bank, International Bank of Commerce, Zapata, International Bank of Commerce, Brownsville and the Corporation’s wholly-owned non-bank subsidiaries, IBC Subsidiary Corporation, IBC Life Insurance Company, IBC Trading Company, IBC Capital Corporation and Premier Tierra Holdings, Inc.  All significant inter-company balances and transactions have been eliminated in consolidation.  The consolidated financial statements are unaudited, but include all adjustments, which, in the opinion of management, are necessary for a fair presentation of the results of the periods presented.  All such adjustments were of a normal and recurring nature.  It is suggested that these financial statements be read in conjunction with the financial statements and the notes thereto in the Company’s latest Annual Report on Form 10-K.  The consolidated statement of condition at December 31, 2013 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete financial statements.  Certain reclassifications have been made to make prior periods comparable.
	The Company operates as one segment.  The operating information used by the Company’s chief executive officer for purposes of assessing performance and making operating decisions about the Company is the consolidated statements presented in this report.  The Company has four active operating subsidiaries, namely, the bank subsidiaries, otherwise known as International Bank of Commerce, Laredo, Commerce Bank, International Bank of Commerce, Zapata and International Bank of Commerce, Brownsville.  The Company applies the provisions of Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”), FASB ASC 280, “Segment Reporting”, in determining its reportable segments and related disclosures.
	The Company has evaluated all events or transactions that occurred through the date the Company issued these financial statements. During this period, the Company did not have any material recognizable or non-recognizable subsequent events.

Fair_Value_Measurements

Fair Value Measurements

3 Months Ended

Mar. 31, 2014

Fair Value Measurements

'

Fair Value Measurements

'

Note 2 — Fair Value Measurements

ASC Topic 820, “Fair Value Measurements and Disclosures” (“ASC 820”) defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles, and expands disclosures about fair value measurements.  ASC 820 applies to all financial instruments that are being measured and reported on a fair value basis.  ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date; it also establishes a fair value hierarchy that prioritizes the inputs used in valuation methodologies into the following three levels:

·                  Level 1 Inputs — Unadjusted quoted prices in active markets for identical assets or liabilities.

·                  Level 2 Inputs — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

·                  Level 3 Inputs — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.  Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or other valuation techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.

A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy is set forth below.

The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value as of March 31, 2014 by level within the fair value measurement hierarchy:

Fair Value Measurements at Reporting Date Using

(Dollars in Thousands)

Assets/Liabilities

Quoted Prices

Significant Other

Significant

Measured at Fair

in Active

Observable

Unobservable

Value

Markets for

Inputs

Inputs

Identical

Assets

March 31, 2014

(Level 1)

(Level 2)

(Level 3)

Measured on a recurring basis:

Assets:

Available for sale securities

Residential mortgage-backed securities

$

4,932,505

$

—

$

4,905,549

$

26,956

States and political subdivisions

261,125

—

261,125

—

Other

28,927

28,927

—

—

$

5,222,557

$

28,927

$

5,166,674

$

26,956

The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value as of December 31, 2013 by level within the fair value measurement hierarchy:

Fair Value Measurements at Reporting Date Using

(Dollars in Thousands)

Assets/Liabilities

Quoted Prices

Significant Other

Significant

Measured at

in Active

Observable

Unobservable

Fair Value

Markets for

Inputs

Inputs

December 31,

Identical

(Level 2)

(Level 3)

2013

Assets

(Level 1)

Measured on a recurring basis:

Assets:

Available for sale securities

Residential mortgage-backed securities

$

5,027,701

$

—

$

4,999,849

$

27,852

States and political subdivisions

248,410

—

248,410

—

Other

28,468

28,468

—

—

$

5,304,579

$

28,468

$

5,248,259

$

27,852

Investment securities available-for-sale are classified within level 2 and level 3 of the valuation hierarchy, with the exception of certain equity investments that are classified within level 1.  For investments classified as level 2 in the fair value hierarchy, the Company obtains fair value measurements for investment securities from an independent pricing service.  The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things.  Investment securities classified as level 3 are non-agency mortgage-backed securities.  The non-agency mortgage-backed securities held by the Company are traded in inactive markets and markets that have experienced significant decreases in volume and level of activity, as evidenced by few recent transactions, a significant decline or absence of new issuances, price quotations that are not based on comparable securities transactions and wide bid-ask spreads among other factors.  As a result of the inability to use quoted market prices to determine fair value for these securities, the Company determined that fair value, as determined by level 3 inputs in the fair value hierarchy, is more appropriate for financial reporting and more consistent with the expected performance of the investments.  For the investments classified within level 3 of the fair value hierarchy, the Company used a discounted cash flow model to determine fair value.  Inputs in the model included both historical performance and expected future performance based on information currently available.

Assumptions used in the discounted cash flow model as of March 31, 2014 and December 31, 2013, were applied separately to those portions of the bond where the underlying residential mortgage loans had been performing under original contract terms for at least the prior 24 months and those where the underlying residential mortgages had not been meeting the original contractual obligation for the same period.  Unobservable inputs included in the model are estimates on future principal prepayment rates, and default and loss severity rates.  For that portion of the bond where the underlying residential mortgage had been meeting the original contract terms for at least 24 months, the Company used the following estimates in the model: (i) a voluntary prepayment rate of 7%, (ii) a 1% default rate, (iii) a loss severity rate of 25%, and (iv) a discount rate of 13%.  The assumptions used in the model for the rest of the bond included the following estimates:  (i) a voluntary prepayment rate of 2 %, (ii) a default rate of 4.5%, (iii) a loss severity rate that started at 60% for the first year (2012)  then declines by 5% for the following five years (2013, 2014, 2015, 2016 and 2017) and remains at 25% thereafter (2018 and beyond), and (iv) a discount rate of 13%.  The estimates used in the model to determine fair value are based on observable historical data of the underlying collateral.  The model anticipates that the housing market will gradually improve and that the underlying collateral will eventually all perform in accordance with the original contract terms on the bond.  Should the number of loans in the underlying collateral that default and go into foreclosure or the severity of the losses in the underlying collateral significantly change, the results of the model would be impacted.  The Company will continue to evaluate the actual historical performance of the underlying collateral and will modify the assumptions used in the model as necessary.

The following table presents a reconciliation of activity for such mortgage-backed securities on a net basis (Dollars in Thousands):

Balance at December 31, 2013

$

27,852

Principal paydowns

(928

)

Total unrealized gains included in:

Other comprehensive loss

122

Impairment realized

(90

)

Balance at March 31, 2014

$

26,956

Certain financial assets and financial liabilities are measured at fair value on a nonrecurring basis.  The instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment).

The following table represents financial instruments measured at fair value on a non-recurring basis as of March 31, 2014 by level within the fair value measurement hierarchy:

Fair Value Measurements at Reporting Date

Using

(Dollars in Thousands)

Assets/Liabilities

Quoted

Significant

Significant

Net Provision

Measured at Fair

Prices in

Other

Unobservable

During

Value

Active

Observable

Inputs

Three Month

March 31, 2014

Markets for

Inputs

(Level 3)

Period

Identical

(Level 2)

Assets

(Level 1)

Measured on a non-recurring basis:

Assets:

Impaired loans

$

21,419

$

—

$

—

$

21,419

$

5,208

Other real estate owned

5,152

—

—

5,152

138

The following table represents financial instruments measured at fair value on a non-recurring basis as of December 31, 2013 by level within the fair value measurement hierarchy:

Fair Value Measurements at Reporting Date

Using

(Dollars in Thousands)

Assets/Liabilities

Quoted

Significant

Significant

Net

Measured at Fair

Prices in

Other

Unobservable

Provision

Value

Active

Observable

Inputs

During

December 31,

Markets for

Inputs

(Level 3)

Twelve Month

2013

Identical

(Level 2)

Period

Assets

(Level 1)

Measured on a non-recurring basis:

Assets:

Impaired loans

$

28,391

$

—

$

—

$

28,391

$

13,229

Other real estate owned

16,329

—

—

16,329

1,204

The Company’s assets measured at fair value on a non-recurring basis are limited to impaired loans and other real estate owned.  Impaired loans are classified within level 3 of the valuation hierarchy.  The fair value of impaired loans is derived in accordance with FASB ASC 310, “Receivables”.  Impaired loans are primarily comprised of collateral-dependent commercial loans.  The fair value of impaired loans is based on the fair value of the collateral, as determined through either an appraisal or evaluation process.  The basis for the Company’s appraisal and appraisal review process is based on regulatory guidelines and strives to comply with all regulatory appraisal laws, regulations and the Uniform Standards of Professional Appraisal Practice.  Understanding that as the primary sources of loan repayments decline, the secondary repayment source comes into play and correctly evaluating the fair value of that secondary source, the collateral, becomes even more important.  As part of the weekly credit quality meetings and the determination of the loan loss provision, obsolete appraisals are identified.  Appraisals are considered for each type of impaired collateral dependent loan and new or updated appraisals may be obtained as warranted after evaluation of any material deterioration in the performance of the project or changes in project specifications, the economic conditions for the geographic area where the property is located, a change in the use of the property, differences between the current property conditions and the conditions assumed in prior appraisals or evaluations, or, if it’s an income producing property, changes in the cash flow on the property.  All appraisals and evaluations are “as is” (the property’s highest and best use) valuations based on the current conditions of the property/project at that point in time.  The determination of the fair value of the collateral is based on the net realizable value, which is the appraised value less any closing costs, when applicable.  Impaired loans are remeasured and reported at fair value through a specific valuation allowance allocation of the allowance for probable loan losses based upon the fair value of the underlying collateral.  As of March 31, 2014, the Company had $65,436,000 of impaired commercial collateral dependent loans, of which $43,571,000  had an appraisal or evaluation performed within the immediately preceding twelve months.  As of December 31, 2013, the Company had $64,585,000 of impaired commercial collateral dependent loans, of which $50,346,000 had an appraisal or evaluation performed within the immediately preceding twelve months.

Other real estate owned is comprised of real estate acquired by foreclosure and deeds in lieu of foreclosure. Other real estate owned is carried at the lower of the recorded investment in the property or its fair value less estimated costs to sell such property (as determined by independent appraisal) within level 3 of the fair value hierarchy.  Prior to foreclosure, the value of the underlying loan is written down to the fair value of the real estate to be acquired by a charge to the allowance for probable loan losses, if necessary.  The fair value is reviewed periodically and subsequent write downs are made accordingly through a charge to operations.  Other real estate owned is included in other assets on the consolidated financial statements.  For the three months ended March 31, 2014 and the twelve months ended December 31, 2013, respectively the Company recorded $37,000 and $402,000  in charges to the allowance for probable loan losses in connection with loans transferred to other real estate owned.  For the three months ended March 31, 2014 and twelve months ended December 31, 2013, respectively, the Company recorded $138,000 and $1,204,000  in adjustments to fair value in connection with other real estate owned.

The fair value estimates, methods, and assumptions for the Company’s financial instruments at March 31, 2014 and December 31, 2013 are outlined below.

Cash and Due From Banks and Federal Funds Sold

For these short-term instruments, the carrying amount is a reasonable estimate of fair value.

Time Deposits with Banks

The carrying amounts of time deposits with banks approximate fair value.

Investment Securities Held-to-Maturity

The carrying amounts of investments held-to-maturity approximate fair value.

Investment Securities

For investment securities, which include U.S. Treasury securities, obligations of other U.S. government agencies, obligations of states and political subdivisions and mortgage pass through and related securities, fair values are from an independent pricing service.  The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things.  See disclosures of fair value of investment securities in Note 6.

Loans

Fair values are estimated for portfolios of loans with similar financial characteristics.  Loans are segregated by type such as commercial, real estate and consumer loans as outlined by regulatory reporting guidelines.  Each category is segmented into fixed and variable interest rate terms and by performing and non-performing categories.

For variable rate performing loans, the carrying amount approximates the fair value.  For fixed rate performing loans, except residential mortgage loans, the fair value is calculated by discounting scheduled cash flows through the estimated maturity using estimated market discount rates that reflect the credit and interest rate risk inherent in the loan.  For performing residential mortgage loans, fair value is estimated by discounting contractual cash flows adjusted for prepayment estimates using discount rates based on secondary market sources or the primary origination market.  Fixed rate performing loans are within Level 3 of the fair value hierarchy.  At March 31, 2014, and December 31, 2013, the carrying amount of fixed rate performing loans was $1,254,640,000 and $1,243,252,000 respectively, and the estimated fair value was $1,206,449,000 and $1,196,916,000, respectively.

Accrued Interest

The carrying amounts of accrued interest approximate fair value.

Deposits

The fair value of deposits with no stated maturity, such as non-interest bearing demand deposit accounts, savings accounts and interest bearing demand deposit accounts, was equal to the amount payable on demand as of March 31, 2014 and December 31, 2013.  The fair value of time deposits is based on the discounted value of contractual cash flows.  The discount rate is based on currently offered rates.  Time deposits are within Level 3 of the fair value hierarchy.  At March 31, 2014 and December 31, 2013, the carrying amount of time deposits was $2,640,186,000 and $2,651,303,000, respectively, and the estimated fair value was $2,638,519,000 and $2,648,452,000, respectively.

Securities Sold Under Repurchase Agreements

Securities sold under repurchase agreements include both short and long-term maturities.  Due to the contractual terms of the short-term instruments, the carrying amounts approximated fair value at March 31, 2014 and December 31, 2013.  The fair value of the long-term instruments is based on established market spreads using option adjusted spread methodology.  Long-term repurchase agreements are within level 3 of the fair value hierarchy.  At March 31, 2014 and December 31, 2013, respectively, the carrying amount of long-term repurchase agreements was $610,000,000 and $710,000,000 and the estimated fair value was $674,938,000 and $792,215,500, respectively.

Junior Subordinated Deferrable Interest Debentures

The Company currently has floating rate junior subordinated deferrable interest debentures outstanding.  Due to the contractual terms of the floating rate junior subordinated deferrable interest debentures, the carrying amounts approximated fair value at March 31, 2014 and December 31, 2013.

Other Borrowed Funds

The company currently has short and long-term borrowings issued from the Federal Home Loan Bank (“FHLB”).  Due to the contractual terms of the short-term borrowings, the carrying amounts approximated fair value at March 31, 2014 and December 31, 2013.  The fair value of the long-term borrowings is based on established market spreads for similar types of borrowings.  The long-term borrowings are included in Level 2 of the fair value hierarchy.  At March 31, 2014 and December 31, 2013, the carrying amount of the long-term FHLB borrowings was $8,903,000, and $8,951,000, respectively, and the estimated fair value was $8,911,000 and $8,950,000, respectively.

Commitments to Extend Credit and Letters of Credit

Commitments to extend credit and fund letters of credit are principally at current interest rates, and, therefore, the carrying amount approximates fair value.

Limitations

Fair value estimates are made at a point in time, based on relevant market information and information about the financial instrument.  These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument.  Because no market exists for a significant portion of the Company’s financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments and other factors.  These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision.  Changes in assumptions could significantly affect the estimates.

Fair value estimates are based on existing on-and off-statement of condition financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments.  Other significant assets and liabilities that are not considered financial assets or liabilities include the bank premises and equipment and core deposit value.  In addition, the tax ramifications related to the effect of fair value estimates have not been considered in the above estimates.

Loans

Loans	3 Months Ended
	Mar. 31, 2014
Loans	'
Loans	'
	Note 3— Loans
	A summary of loans, by loan type at March 31, 2014 and December 31, 2013 is as follows:
		March 31,		December 31,
		2014		2013
		(Dollars in Thousands)
	Commercial, financial and agricultural	$	2,924,592	$	2,894,779
	Real estate — mortgage	840,165		847,692
	Real estate — construction	1,279,003		1,208,508
	Consumer	63,430		66,414
	Foreign	179,310		181,842
	Total loans	$	5,286,500	$	5,199,235

Allowance_for_Probable_Loan_Lo

Allowance for Probable Loan Losses	3 Months Ended
	Mar. 31, 2014
Allowance for Probable Loan Losses	'
Allowance for Probable Loan Losses	'
	Note 4 - Allowance for Probable Loan Losses
	The allowance for probable loan losses primarily consists of the aggregate loan loss allowances of the bank subsidiaries.  The allowances are established through charges to operations in the form of provisions for probable loan losses.  Loan losses or recoveries are charged or credited directly to the allowances.  The allowance for probable loan losses of each bank subsidiary is maintained at a level considered appropriate by management, based on estimated probable losses in the loan portfolio.  The allowance for probable loan losses is derived from the following elements:  (i) allowances established on specific impaired loans, which are based on a review of the individual characteristics of each loan, including the customer’s ability to repay the loan, the underlying collateral values, and the industry in which the customer operates, (ii) allowances based on actual historical loss experience for similar types of loans in the Company’s loan portfolio, and (iii) allowances based on general economic conditions, changes in the mix of loans, company resources, border risk and credit quality indicators, among other things.  All segments of the loan portfolio continue to be impacted by the prolonged economic downturn.  Loans secured by real estate could be impacted negatively by the continued economic environment and resulting decrease in collateral values.  Consumer loans may be impacted by continued and prolonged unemployment rates.
	The Company’s management continually reviews the allowance for loan losses of the bank subsidiaries using the amounts determined from the allowances established on specific impaired loans, the allowance established on quantitative historical loss percentages, and the allowance based on qualitative data to establish an appropriate amount to maintain in the Company’s allowance for loan losses.  Should any of the factors considered by management in evaluating the adequacy of the allowance for probable loan losses change, the Company’s estimate of probable loan losses could also change, which could affect the level of future provisions for probable loan losses.  While the calculation of the allowance for probable loan losses utilizes management’s best judgment and all information available, the adequacy of the allowance is dependent on a variety of factors beyond the Company’s control, including, among other things, the performance of the entire loan portfolio, the economy, changes in interest rates and the view of regulatory authorities towards loan classifications.
	The loan loss provision is determined using the following methods.  On a weekly basis, loan past due reports are reviewed by the credit quality committee to determine if a loan has any potential problems and if a loan should be placed on the Company’s internal classified report.  Additionally, the Company’s credit department reviews the majority of the Company’s loans for proper internal classification purposes regardless of whether they are past due and segregates any loans with potential problems for further review.  The credit department will discuss the potential problem loans with the servicing loan officers to determine any relevant issues that were not discovered in the evaluation.  Also, an analysis of loans that is provided through examinations by regulatory authorities is considered in the review process.  After the above analysis is completed, the Company will determine if a loan should be placed on an internal classified report because of issues related to the analysis of the credit, credit documents, collateral and/or payment history.
	A summary of the transactions in the allowance for probable loan losses by loan class is as follows:
		Three Months Ended March 31, 2014
		Domestic																					Foreign
		Commercial			Commercial			Commercial			Commercial			Residential:			Residential:			Consumer			Foreign			Total
					real estate:			real estate:			real estate:			first lien			junior lien
					other			farmland &			multifamily
					construction &			commercial
					land
					development
		(Dollars in Thousands)
	Balance at December 31, 2013	$	22,433		$	12,541		$	24,467		$	776		$	3,812		$	4,249		$	750		$	1,133		$	70,161
	Losses charge to allowance	(2,481		)	—			—			—			(27		)	(146		)	(187		)	(3		)	(2,844		)
	Recoveries credited to allowance	796			31			23			—			4			33			80			46			1,013
	Net losses charged to allowance	(1,685		)	31			23			—			(23		)	(113		)	(107		)	43			(1,831		)
	Provision charged to operations	7,175			903			(5,556		)	43			(265		)	(168		)	105			(159		)	2,078
	Balance at March 31, 2014	$	27,923		$	13,475		$	18,934		$	819		$	3,524		$	3,968		$	748		$	1,017		$	70,408
		Three Months Ended March 31, 2013
		Domestic																					Foreign
		Commercial			Commercial			Commercial			Commercial			Residential:			Residential:			Consumer			Foreign			Total
					real estate:			real estate:			real estate:			first lien			junior lien
					other			farmland &			multifamily
					construction &			commercial
					land
					development
		(Dollars in Thousands)
	Balance at December 31, 2012	$	11,632		$	12,720		$	21,880		$	694		$	4,390		$	4,448		$	1,289		$	1,140		$	58,193
	Losses charge to allowance	(2,663		)	(128		)	(60		)	—			(172		)	(255		)	(211		)	(20		)	(3,509		)
	Recoveries credited to allowance	694			13			13			—			5			94			46			—			865
	Net losses charged to allowance	(1,969		)	(115		)	(47		)	—			(167		)	(161		)	(165		)	(20		)	(2,644		)
	Provision charged to operations	11,263			(1,552		)	(1,182		)	(85		)	(355		)	(276		)	(304		)	(90		)	7,419
	Balance at March 31, 2013	$	20,926		$	11,053		$	20,651		$	609		$	3,868		$	4,011		$	820		$	1,030		$	62,968
	The allowance for probable loan losses is a reserve established through a provision for probable loan losses charged to expense, which represents management’s best estimate of probable loan losses when evaluating loans (i) individually or (ii) collectively.
	The table below provides additional information on the balance of loans individually or collectively evaluated for impairment and their related allowance, by loan class as of March 31, 2014 and December 31, 2013:
		March 31, 2014
		Loans individually evaluated						Loans collectively evaluated
		for impairment						for impairment
		Recorded			Allowance			Recorded			Allowance
		Investment						Investment
		(Dollars in Thousands)
	Domestic
	Commercial	$	35,539		$	17,424		$	1,059,024		$	10,499
	Commercial real estate: other construction & land development	13,558			852			1,265,445			12,623
	Commercial real estate: farmland & commercial	15,607			2,666			1,706,316			16,268
	Commercial real estate: multifamily	280			—			107,826			819
	Residential: first lien	6,273			—			414,736			3,524
	Residential: junior lien	3,123			—			416,033			3,968
	Consumer	1,453			—			61,977			748
	Foreign	430			—			178,880			1,017
	Total	$	76,263		$	20,942		$	5,210,237		$	49,466
		December 31, 2013
		Loans individually evaluated						Loans collectively evaluated
		for impairment						for impairment
		Recorded			Allowance			Recorded			Allowance
		Investment						Investment
		(Dollars in Thousands)
	Domestic
	Commercial	$	34,183		$	12,234		$	1,008,459		$	10,199
	Commercial real estate: other construction & land development	13,976			852			1,194,532			11,689
	Commercial real estate: farmland & commercial	16,038			2,916			1,734,001			21,551
Commercial real estate: multifamily	295			—			101,803			776
Residential: first lien	6,153			—			432,309			3,812
Residential: junior lien	3,206			—			406,024			4,249
Consumer	1,606			—			64,808			750
Foreign	436			—			181,406			1,133
Total	$	75,893		$	16,002		$	5,123,342		$	54,159
The table below provides additional information on loans accounted for on a non-accrual basis by loan class at March 31, 2014 and December 31, 2013:
	March 31, 2014			December 31, 2013
	(Dollars in Thousands)
Domestic
Commercial	$	35,476		$	34,110
Commercial real estate: other construction & land development	11,307			11,726
Commercial real estate: farmland & commercial	13,344			13,775
Commercial real estate: multifamily	280			295
Residential: first lien	1,259			1,266
Residential: junior lien	1,555			1,576
Consumer	45			75
Total non-accrual loans	$	63,266		$	62,823
Impaired loans are those loans where it is probable that all amounts due according to contractual terms of the loan agreement will not be collected.  The Company has identified these loans through its normal loan review procedures.  Impaired loans are measured based on (1) the present value of expected future cash flows discounted at the loan’s effective interest rate; (2) the loan’s observable market price; or (3) the fair value of the collateral if the loan is collateral dependent.  Substantially all of the Company’s impaired loans are measured at the fair value of the collateral. In limited cases the Company may use other methods to determine the level of impairment of a loan if such loan is not collateral dependent.
The following tables detail key information regarding the Company’s impaired loans by loan class at March 31, 2014 and December 31, 2013:
	March 31, 2014
	Recorded			Unpaid			Related			Average			Interest
	Investment			Principal			Allowance			Recorded			Recognized
				Balance						Investment
	(Dollars in Thousands)
Loans with Related Allowance
Domestic
Commercial	$	17,684		$	17,674		$	17,424		$	17,287		$	—
Commercial real estate: other construction & land development	6,898			6,906			852			6,898			—
Commercial real estate: farmland & commercial	6,615			6,963			2,666			6,624			23
Total impaired loans with related allowance	$	31,197		$	31,553		$	20,942		$	30,809		$	23
	March 31, 2014
	Recorded			Unpaid Principal			Average			Interest
	Investment			Balance			Recorded			Recognized
							Investment
	(Dollars in Thousands)
Loans with No Related Allowance
Domestic
Commercial	$	17,855		$	17,876		$	17,060		$	1
Commercial real estate: other construction & land development	6,660			6,704			6,801			18
Commercial real estate: farmland & commercial	8,992			10,310			8,656			—
Commercial real estate: multifamily	280			280			285			—
Residential: first lien	6,273			6,337			6,287			63
Residential: junior lien	3,123			3,142			3,133			24
Consumer	1,453			1,460			1,444			1
Foreign	430			430			432			5
Total impaired loans with no related allowance	$	45,066		$	46,539		$	44,098		$	112
	December 31, 2013
	Recorded			Unpaid			Related			Average			Interest
	Investment			Principal			Allowance			Recorded			Recognized
				Balance						Investment
	(Dollars in Thousands)
Loans with Related Allowance
Domestic
Commercial	$	17,178		$	17,177		$	12,234		$	18,019		$	38
Commercial real estate: other construction & land development	6,818			6,825			852			6,058			—
Commercial real estate: farmland & commercial	7,259			10,697			2,916			7,167			92
Total impaired loans with related allowance	$	31,255		$	34,699		$	16,002		$	31,244		$	130
	December 31, 2013
	Recorded			Unpaid Principal			Average			Interest
	Investment			Balance			Recorded			Recognized
							Investment
	(Dollars in Thousands)
Loans with No Related Allowance
Domestic
Commercial	$	17,005		$	17,023		$	16,778		$	2
Commercial real estate: other construction & land development	7,158			7,187			18,164			74
Commercial real estate: farmland & commercial	8,779			9,949			7,313			—
Commercial real estate: multifamily	295			295			322			—
Residential: first lien	6,153			6,258			4,860			179
Residential: junior lien	3,206			3,226			2,347			99
Consumer	1,606			1,612			1,380			1
Foreign	436			436			452			19
Total impaired loans with no related allowance	$	44,638		$	45,986		$	51,616		$	374
A portion of the impaired loans have adequate collateral and credit enhancements not requiring a related allowance for loan loss.  The level of impaired loans is reflective of the economic weakness that has been created by the financial crisis and the subsequent economic downturn.  Management is confident the Company’s loss exposure regarding these credits will be significantly reduced due to the Company’s long-standing practices that emphasize secured lending with strong collateral positions and guarantor support.  Management is likewise confident the reserve for probable loan losses is adequate.  The Company has no direct exposure to sub-prime loans in its loan portfolio, but the sub-prime crisis has affected the credit markets on a national level, and as a result, the Company has experienced an increasing amount of impaired loans; however, management’s decision to place loans in this category does not necessarily mean that the Company will experience significant losses from these loans or significant increases in impaired loans from these levels.
Management of the Company recognizes the risks associated with these impaired loans.  However, management’s decision to place loans in this category does not necessarily mean that losses will occur. In the current environment, troubled loan management can be protracted because of the legal and process problems that delay the collection of an otherwise collectable loan.  Additionally, management believes that the collateral related to these impaired loans and/or the secondary support from guarantors mitigates the potential for losses from impaired loans.  It is also important to note that even though the economic conditions in Texas and Oklahoma are weakened, we believe these markets are continuing to improve and continue to be in a position to recover better than many other areas of the country.  Loans accounted for as “troubled debt restructuring,” which are included in impaired loans, were not significant and totaled $19,148,000 and $20,358,000 as of March 31, 2014 and December 31, 2013, respectively.
The bank subsidiaries charge off that portion of any loan which management considers to represent a loss as well as that portion of any other loan which is classified as a “loss” by bank examiners.  Commercial and industrial or real estate loans are generally considered by management to represent a loss, in whole or part, when an exposure beyond any collateral coverage is apparent and when no further collection of the loss portion is anticipated based on the borrower’s financial condition and general economic conditions in the borrower’s industry. Generally, unsecured consumer loans are charged-off when 90 days past due.
While management of the Company considers that it is generally able to identify borrowers with financial problems reasonably early and to monitor credit extended to such borrowers carefully, there is no precise method of predicting loan losses.  The determination that a loan is likely to be uncollectible and that it should be wholly or partially charged-off as a loss is an exercise of judgment.  Similarly, the determination of the adequacy of the allowance for probable loan losses can be made only on a subjective basis.  It is the judgment of the Company’s management that the allowance for probable loan losses at March 31, 2014 was adequate to absorb probable losses from loans in the portfolio at that date.
The following table presents information regarding the aging of past due loans by loan class at March 31, 2014 and December 31, 2013:
	March 31, 2014
	30 – 59			60 – 89			90			90 Days			Total			Current			Total
	Days			Days			Days or			or			Past						Portfolio
							Greater			greater			due
										& still
										accruing
	(Dollars in Thousands)
Domestic
Commercial	$	4,622		$	1,477		$	35,819		$	2,225		$	41,918		$	1,052,645		$	1,094,563
Commercial real estate: other construction & land development	642			309			10,537			68			11,488			1,267,515			1,279,003
Commercial real estate: farmland & commercial	4,988			2,861			7,327			1,099			15,176			1,706,747			1,721,923
Commercial real estate: multifamily	343			217			280			—			840			107,266			108,106
Residential: first lien	5,211			1,005			2,613			1,588			8,829			412,180			421,009
Residential: junior lien	855			96			1,708			183			2,659			416,497			419,156
Consumer	1,119			489			884			842			2,492			60,938			63,430
Foreign	2,016			10			329			329			2,355			176,955			179,310
Total past due loans	$	19,796		$	6,464		$	59,497		$	6,334		$	85,757		$	5,200,743		$	5,286,500
	December 31, 2013
	30 – 59			60 – 89			90 Days or			90 Days			Total			Current			Total
	Days			Days			Greater			or			Past						Portfolio
										greater			due
										& still
										accruing
	(Dollars in Thousands)
Domestic
Commercial	$	4,240		$	538		$	36,066		$	2,051		$	40,844		$	1,001,798		$	1,042,642
Commercial real estate: other construction & land development	1,042			—			9,942			62			10,984			1,197,524			1,208,508
Commercial real estate: farmland & commercial	6,216			520			6,990			417			13,726			1,736,313			1,750,039
Commercial real estate: multifamily	39			142			295			—			476			101,622			102,098
Residential: first lien	4,758			3,046			4,541			3,518			12,345			426,117			438,462
Residential: junior lien	606			198			1,900			368			2,704			406,526			409,230
Consumer	1,523			469			803			781			2,795			63,619			66,414
Foreign	1,467			417			—			—			1,884			179,958			181,842
Total past due loans	$	19,891		$	5,330		$	60,537		$	7,197		$	85,758		$	5,113,477		$	5,199,235
The Company’s internal classified report is segregated into the following categories:  (i) “Special Review Credits,” (ii) “Watch List - Pass Credits,” or (iii) “Watch List - Substandard Credits.”  The loans placed in the “Special Review Credits” category reflect the Company’s opinion that the loans reflect potential weakness which require monitoring on a more frequent basis.  The “Special Review Credits” are reviewed and discussed on a regular basis with the credit department and the lending staff to determine if a change in category is warranted.  The loans placed in the “Watch List - Pass Credits” category reflect the Company’s opinion that the credit contains weaknesses which represent a greater degree of risk, which warrant “extra attention.”  The “Watch List — Pass Credits” are reviewed and discussed on a regular basis with the credit department and the lending staff to determine if a change in category is warranted.  The loans placed in the “Watch List — Substandard Credits” classification are considered to be potentially inadequately protected by the current sound worth and debt service capacity of the borrower or of any pledged collateral.  These credit obligations, even if apparently protected by collateral value, have shown defined weaknesses related to adverse financial, managerial, economic, market or political conditions which may jeopardize repayment of principal and interest.  Furthermore, there is the possibility that some future loss could be sustained by the Company if such weaknesses are not corrected.  For loans that are classified as impaired, management evaluates these credits ASC 310-10, “Receivables,” and, if deemed necessary, a specific reserve is allocated to the credit.  The specific reserve allocated under ASC 310-10, is based on (i) the present value of expected future cash flows discounted at the loan’s effective interest rate; (ii) the loan’s observable market price; or (iii) the fair value of the collateral if the loan is collateral dependent.  Substantially all of the Company’s loans evaluated as impaired under ASC 310-10 are measured using the fair value of collateral method.  In limited cases, the Company may use other methods to determine the specific reserve of a loan under ASC 310-10 if such loan is not collateral dependent.
The allowance based on historical loss experience on the Company’s remaining loan portfolio, which includes the “Special Review Credits,” “Watch List - Pass Credits,” and “Watch List - Substandard Credits” is determined by segregating the remaining loan portfolio into certain categories such as commercial loans, installment loans, international loans, loan concentrations and overdrafts.  Installment loans are then further segregated by number of days past due.  A historical loss percentage, adjusted for (i) management’s evaluation of changes in lending policies and procedures, (ii) current economic conditions in the market area served by the Company, (iii) other risk factors, (iv) the effectiveness of the internal loan review function, (v) changes in loan portfolios, and (vi) the composition and concentration of credit volume is applied to each category.  Each category is then added together to determine the allowance allocated under ASC 450-20.
A summary of the loan portfolio by credit quality indicator by loan class at March 31, 2014 and December 31, 2013 is as follows:
				March 31, 2014
	Pass			Special			Watch List			Watch List -			Watch List -
				Review			- Pass			Substandard			Impaired
				(Dollars in Thousands)
Domestic
Commercial	$	1,001,514		$	7,213		$	4,887		$	45,410		$	35,539
Commercial real estate: other construction & land development	1,242,189			6,296			8,577			8,383			13,558
Commercial real estate: farmland & commercial	1,608,212			61,709			22,371			14,024			15,607
Commercial real estate: multifamily	106,984			—			—			842			280
Residential: first lien	414,523			118			—			95			6,273
Residential: junior lien	415,575			—			—			458			3,123
Consumer	61,977			—			—			—			1,453
Foreign	178,542			—			—			338			430
Total	$	5,029,516		$	75,336		$	35,835		$	69,550		$	76,263
				December 31, 2013
	Pass			Special			Watch List			Watch List -			Watch List -
				Review			- Pass			Substandard			Impaired
				(Dollars in Thousands)
Domestic
Commercial	$	955,522		$	2,270		$	4,389		$	46,278		$	34,183
Commercial real estate: other construction & land development	1,167,295			14,247			9,318			3,672			13,976
Commercial real estate: farmland & commercial	1,635,179			56,438			21,912			20,472			16,038
Commercial real estate: multifamily	100,948			—			—			855			295
Residential: first lien	432,067			122			—			120			6,153
Residential: junior lien	405,731			—			—			293			3,206
Consumer	64,808			—			—			—			1,606
Foreign	180,837			—			—			569			436
Total	$	4,942,387		$	73,077		$	35,619		$	72,259		$	75,893

Stock_Options

Stock Options	3 Months Ended
	Mar. 31, 2014
Stock Options	'
Stock Options	'
	Note 5 — Stock Options
	On April 5, 2012, the Board of Directors adopted the 2012 International Bancshares Corporation Stock Option Plan (the “2012 Plan”). There are 800,000 shares available for stock option grants under the 2012 Plan. Under the 2012 Plan, both qualified incentive stock options (“ISOs”) and non-qualified stock options (“NQSOs”) may be granted. Options granted may be exercisable for a period of up to 10 years from the date of grant, excluding ISOs granted to 10% shareholders, which may be exercisable for a period of up to only five years. As of March 31, 2014, 199,250 shares were available for future grants under the 2012 Plan.
	A summary of option activity under the stock option plan for the three months ended March 31, 2014 is as follows:
		Number of	Weighted		Weighted	Aggregate
		options	average		average	intrinsic
			exercise price		remaining	value ($)
					contractual term
					(years)
						(Dollars in Thousands)
	Options outstanding at December 31, 2013	515,143	$	15.98
	Plus: Options granted	549,750	21.42
	Less:
	Options exercised	8,399	14.23
	Options expired	—	—
	Options forfeited	500	10.4
	Options outstanding at March 31, 2014	1,055,994	18.83		6	6,711
	Options fully vested and exercisable at March 31, 2014	222,942	18.43		2.42	1,593
	Stock-based compensation expense included in the consolidated statements of income for the three months ended March 31, 2014 and March 31, 2013 was approximately $161,000 and $114,000, respectively.  As of March 31, 2014, there was approximately $4,831,000 of total unrecognized stock-based compensation cost related to non-vested options granted under the Company plans that will be recognized over a weighted average period of 2.6 years.

Investment_Securities

Investment Securities	3 Months Ended
	Mar. 31, 2014
Investment Securities	'
Investment Securities	'
	Note 6 - Investment Securities
	The Company classifies debt and equity securities into one of three categories:  held-to maturity, available-for-sale, or trading.  Such securities are reassessed for appropriate classification at each reporting date.  Securities classified as “held-to-maturity” are carried at amortized cost for financial statement reporting, while securities classified as “available-for-sale” and “trading” are carried at their fair value.  Unrealized holding gains and losses are included in net income for those securities classified as “trading”, while unrealized holding gains and losses related to those securities classified as “available-for-sale” are excluded from net income and reported net of tax as other comprehensive income (loss) and accumulated other comprehensive income (loss) until realized, or in the case of losses, when deemed other than temporary.
	The amortized cost and estimated fair value by type of investment security at March 31, 2014 are as follows:
		Held to Maturity
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value
				Gains			Losses
		(Dollars in Thousands)
	Other securities	$	2,400	$	—		$	—		$	2,400		$	2,400
	Total investment securities	$	2,400	$	—		$	—		$	2,400		$	2,400
		Available for Sale
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value (1)
				Gains			Losses
		(Dollars in Thousands)
	Residential mortgage-backed securities	$	4,976,280	$	52,022		$	(95,797	)	$	4,932,505		$	4,932,505
	Obligations of states and political subdivisions	255,085		12,780			(6,740		)	261,125			261,125
	Equity securities	28,075		1,243			(391		)	28,927			28,927
	Total investment securities	$	5,259,440	$	66,045		$	(102,928	)	$	5,222,557		$	5,222,557
	(1)         Included in the carrying value of residential mortgage-backed securities are $ 1,639,116,000 of mortgage-backed securities issued by Ginnie Mae, $3,266,433,000, of mortgage-backed securities issued by Fannie Mae and Freddie Mac and $26,956,000 issued by non-government entities
	The amortized cost and estimated fair value by type of investment security at December 31, 2013 are as follows:
		Held to Maturity
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value
				Gains			Losses
		(Dollars in Thousands)
	Other securities	$	2,400	$	—		$	—		$	2,400		$	2,400
	Total investment securities	$	2,400	$	—		$	—		$	2,400		$	2,400
		Available for Sale
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value (1)
				Gains			Losses
		(Dollars in Thousands)
	Residential mortgage-backed securities	$	5,096,165	$	56,110		$	(124,574	)	$	5,027,701		$	5,027,701
	Obligations of states and political subdivisions	248,354		8,063			(8,007		)	248,410			248,410
	Equity securities	28,075		931			(538		)	28,468			28,468
	Total investment securities	$	5,372,594	$	65,104		$	(133,119	)	$	5,304,579		$	5,304,579
	(1)         Included in the carrying value of residential mortgage-backed securities are $1,799,807 of mortgage-backed securities issued by Ginnie Mae, $3,200,042 of mortgage-backed securities issued by Fannie Mae and Freddie Mac and $27,852 issued by non-government entities
	The amortized cost and estimated fair value of investment securities at March 31, 2014, by contractual maturity, are shown below.  Expected maturities will differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties.
		Held to Maturity					Available for Sale
		Amortized		Estimated			Amortized			Estimated
		Cost		Fair Value			Cost			Fair Value
		(Dollars in Thousands)
	Due in one year or less	$	1,200	$	1,200		$	—		$	—
	Due after one year through five years	1,200		1,200			—			—
	Due after five years through ten years	—		—			712			777
	Due after ten years	—		—			254,373			260,348
	Residential mortgage-backed securities	—		—			4,976,280			4,932,505
	Equity securities	—		—			28,075			28,927
	Total investment securities	$	2,400	$	2,400		$	5,259,440		$	5,222,557
	Residential mortgage-backed securities are securities issued by Freddie Mac, Fannie Mae, Ginnie Mae or non-government entities.  Investments in residential mortgage-backed securities issued by Ginnie Mae are fully guaranteed by the U.S. Government.  Investments in mortgage-backed securities issued by Freddie Mac and Fannie Mae are not fully guaranteed by the U.S. Government, however, the Company believes that the quality of the bonds is similar to other AAA rated bonds with limited credit risk, particularly given the placement of Fannie Mae and Freddie Mac into conservatorship by the federal government in early September 2008 and because securities issued by others that are collateralized by residential mortgage-backed securities issued by Fannie Mae or Freddie Mac are rated consistently as AAA rated securities.
	The amortized cost and fair value of available for sale investment securities pledged to qualify for fiduciary powers, to secure public monies as required by law, repurchase agreements and short-term fixed borrowings was $2,643,050,000 and $2,640,974,000, respectively, at March 31, 2014.
	Proceeds from the sale of securities available-for-sale were $258,277,000 for the three months ended March 31, 2014, which included $257,621,000 of mortgage-backed securities. Gross gains of $8,108,000 and gross losses of $0 were realized on the sales for the three months ended March 31, 2014.  Proceeds from the sale of securities available-for-sale were $178,124,000 for the three months ended March 31, 2013, which included $177,623,000 of mortgage-backed securities. Gross gains of $9,601,000 and gross losses of $0 were realized on the sales for the three months ended March 31, 2013.
	Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at March 31, 2014, were as follows:
		Less than 12 Months					12 Months or More						Total
		Fair Value		Unrealized			Fair Value			Unrealized			Fair Value		Unrealized
				Losses						Losses					Losses
		(Dollars in Thousands)
	Available for sale:
	Residential mortgage-backed securities	$	1,028,459	$	(22,666	)	$	1,747,859		$	(73,131	)	$	2,776,318	$	(95,797	)
	Obligations of states and political subdivisions	35,096		(1,166		)	22,377			(5,574		)	57,473		(6,740		)
	Other equity securities	14,816		(184		)	4,042			(207		)	18,858		(391		)
		$	1,078,371	$	(24,016	)	$	1,774,278		$	(78,912	)	$	2,852,649	$	(102,928	)
Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2013 were as follows:
	Less than 12 Months					12 Months or More						Total
	Fair Value		Unrealized			Fair Value			Unrealized			Fair Value		Unrealized
			Losses						Losses					Losses
	(Dollars in Thousands)
Available for sale:
Residential mortgage-backed securities	$	2,459,565	$	(98,022	)	$	420,262		$	(26,552	)	$	2,879,827	$	(124,574	)
Obligations of states and political subdivisions	55,327		(3,025		)	14,292			(4,982		)	69,619		(8,007		)
Equity securities	19,462		(538		)	—			—			19,462		(538		)
	$	2,534,354	$	(101,585	)	$	434,554		$	(31,534	)	$	2,968,908	$	(133,119	)
The unrealized losses on investments in residential mortgage-backed securities are primarily caused by changes in market interest rates.  Residential mortgage-backed securities are primarily securities issued by Freddie Mac, Fannie Mae and Ginnie Mae.  The contractual cash obligations of the securities issued by Ginnie Mae are fully guaranteed by the U.S. Government.  The contractual cash obligations of the securities issued by Freddie Mac and Fannie Mae are not fully guaranteed by the U.S. Government; however, the Company believes that the quality of the bonds is similar to other AAA rated bonds with limited credit risk, particularly given the placement of Fannie Mae and Freddie Mac into conservatorship by the federal government in early September 2008 and because securities issued by others that are collateralized by residential mortgage-backed securities issued by Fannie Mae and Freddie Mac are rated consistently as AAA rated securities.  The decrease in fair value on residential mortgage-backed securities issued by Freddie Mac, Fannie Mae and Ginnie Mae is due to market interest rates.  The Company has no intent to sell and will more than likely not be required to sell before a market price recovery or maturity of the securities; therefore, it is the conclusion of the Company that the investments in residential mortgage-backed securities issued by Freddie Mac, Fannie Mae and Ginnie Mae are not considered other-than-temporarily impaired.  In addition, the Company has a small investment in non-agency residential mortgage-backed securities that have strong credit backgrounds and include additional credit enhancements to protect the Company from losses arising from high foreclosure rates.  These securities have additional market volatility beyond economically induced interest rate events.  It is the conclusion of the Company that the investments in non-agency residential mortgage-backed securities are other-than-temporarily impaired due to both credit and other than credit issues.  Impairment charges of $90,000 ($58,500, after tax) and $310,000 ($201,500, after tax) were recorded for the quarters ended March 31, 2014 and 2013, respectively.  The impairment charge represents the credit related impairment on the securities.
The unrealized losses on investments in other securities are caused by fluctuations in market interest rates.  The underlying cash obligations of the securities are guaranteed by the entity underwriting the debt instrument.  It is the belief of the Company that the entity issuing the debt will honor its interest payment schedule, as well as the full debt at maturity.  The securities are purchased by the Company for their economic value.  The decrease in fair value is primarily due to market interest rates and not other factors, and because the Company has no intent to sell and will more than likely not be required to sell before a market price recovery or maturity of the securities, it is the conclusion of the Company that the investments are not considered other-than-temporarily impaired.
The following table presents a reconciliation of credit-related impairment charges on available-for-sale investments recognized in earnings for the three months ended March 31, 2014 and 2013, respectively (Dollars in Thousands):
Balance at December 31, 2013	$	11,806
Impairment charges recognized in earnings during period	90
Balance at March 31, 2014	$	11,896
Balance at December 31, 2012	$	10,432
Impairment charges recognized in earnings during period	310
Balance at March 31, 2013	$	10,742

Other_Borrowed_Funds

Other Borrowed Funds	3 Months Ended
	Mar. 31, 2014
Other Borrowed Funds	'
Other Borrowed Funds	'
	Note 7 — Other Borrowed Funds
	Other borrowed funds include Federal Home Loan Bank borrowings, which are short-term and long-term borrowings issued by the FHLB of Dallas at the market price offered at the time of funding.  These borrowings are secured by residential mortgage-backed investment securities and a portion of the Company’s loan portfolio.  At March 31, 2014, other borrowed funds totaled $1,148,403,000, a decrease of 6.2% from $1,223,950,000 at December 31, 2013.  The decrease in other borrowed funds can be attributed to the use of funds generated from the sale of mortgage-backed securities to facilitate a re-positioning of the Company’s investment portfolio.

Junior_Subordinated_Interest_D

Junior Subordinated Interest Deferrable Debentures	3 Months Ended
	Mar. 31, 2014
Junior Subordinated Interest Deferrable Debentures	'
Junior Subordinated Interest Deferrable Debentures	'
	Note 8 — Junior Subordinated Interest Deferrable Debentures
	The Company has formed seven statutory business trusts under the laws of the State of Delaware, for the purpose of issuing trust preferred securities. The seven statutory business trusts formed by the Company (the “Trusts”) have each issued Capital and Common Securities and invested the proceeds thereof in an equivalent amount of junior subordinated debentures (the “Debentures”) issued by the Company. As of March 31, 2014 and December 31, 2013, the principal amount of debentures outstanding totaled $180,416,000 and $190,726,000, respectively. On February 11, 2014, the Company bought back the capital securities of IB Capital Trust VII from the holder of the securities for a price that reflected an approximate 6 percent discount from the redemption price of the securities and thereby retired the $10,310,000 of related Junior Subordinated Deferrable Interest Debentures related to IB Capital Trust VII.
	The Debentures are subordinated and junior in right of payment to all present and future senior indebtedness (as defined in the respective indentures) of the Company, and are pari passu with one another. The interest rate payable on, and the payment terms of the Debentures are the same as the distribution rate and payment terms of the respective issues of Capital and Common Securities issued by the Trusts. The Company has fully and unconditionally guaranteed the obligations of each of the Trusts with respect to the Capital and Common Securities. The Company has the right, unless an Event of Default (as defined in the Indentures) has occurred and is continuing, to defer payment of interest on the Debentures for up to twenty consecutive quarterly periods on Trusts VI, VIII, IX, X, XI and XII. If interest payments on any of the Debentures are deferred, distributions on both the Capital and Common Securities related to that Debenture would also be deferred. The redemption prior to maturity of any of the Debentures may require the prior approval of the Federal Reserve and/or other regulatory bodies.  In February 2014, the Company redeemed all of the outstanding Capital and Common Securities issued by Trust VII.
	For financial reporting purposes, the Trusts are treated as investments of the Company and not consolidated in the consolidated financial statements.  Although the Capital Securities issued by each of the Trusts are not included as a component of shareholders’ equity on the consolidated statement of condition, the Capital Securities are treated as capital for regulatory purposes.  Specifically, under applicable regulatory guidelines, the Capital Securities issued by the Trusts qualify as Tier 1 capital up to a maximum of 25% of Tier 1 capital on an aggregate basis.  Any amount that exceeds the 25% threshold would qualify as Tier 2 capital.  At March 31, 2014 and December 31, 2013, the total $180,416,000 and $190,726,000, respectively, of the Capital Securities outstanding qualified as Tier 1 capital.
	The following table illustrates key information about each of the Capital and Common Securities and their interest rate at March 31, 2014:
		Junior		Repricing	Interest Rate		Interest Rate	Maturity Date	Optional
		Subordinated		Frequency			Index		Redemption
		Deferrable							Date(1)
		Interest
		Debentures
		(Dollars in Thousands)
	Trust VI	$	25,774	Quarterly	3.69	%	LIBOR + 3.45	November 2032	February 2008
	Trust VIII	25,774		Quarterly	3.29	%	LIBOR + 3.05	October 2033	October 2008
	Trust IX	41,238		Quarterly	1.87	%	LIBOR + 1.62	October 2036	October 2011
	Trust X	34,021		Quarterly	1.89	%	LIBOR + 1.65	February 2037	February 2012
	Trust XI	32,990		Quarterly	1.87	%	LIBOR + 1.62	July 2037	July 2012
	Trust XII	20,619		Quarterly	1.69	%	LIBOR + 1.45	September 2037	September 2012
		$	180,416
	(1)         The Capital Securities may be redeemed in whole or in part on any interest payment date after the Optional Redemption Date.

Common_Stock_and_Dividends

Common Stock and Dividends	3 Months Ended
	Mar. 31, 2014
Common Stock and Dividends	'
Common Stock and Dividends	'
	Note 9 — Common Stock and Dividends
	The Company had outstanding 216,000 shares of Series A cumulative perpetual preferred stock (the “Senior Preferred Stock”), issued to the US Treasury under the Company’s participation in the Troubled Asset Relief Program Capital Purchase Program (the “TARP Capital Purchase Program”).  The Company redeemed all of the Senior Preferred Stock in 2012.  In conjunction with the purchase of the Senior Preferred Stock, the US Treasury received a warrant (the “Warrant”) to purchase 1,326,238 shares of the Company’s common stock (the “Warrant Shares”) at $24.43 per share, which would represent an aggregate common stock investment in the Company on exercise of the warrant in full equal to 15% of the Senior Preferred Stock investment.  The term of the Warrant is ten years and was immediately exercisable.  The Warrant is included as a component of Tier 1 capital.  On June 12, 2013, the U.S. Treasury sold the Warrant to a third party.  As of March 31, 2014, the Warrant is still outstanding, but expires on December 23, 2018 with no value if not exercised before that date.
	The Company paid cash dividends to the common shareholders of $.25 per share on April 18, 2014 to all holders of record on April 1, 2014.  The Company paid cash dividends to the common shareholders of $.20 per share on April 20, 2013 to all holders of record on April 1, 2013 and $.23 per share on October 15, 2013 to all holders of record on September 30, 2013, respectively.
	In April 2009, following receipt of the Treasury Department’s consent, the Board of Directors re-established a formal stock repurchase program that authorized the repurchase of up to $40 million of common stock within the following twelve months and on March 7, 2014, the Board of Directors extended the repurchase program and again authorized the repurchase of up to $40 million of common stock during the twelve month period commencing on April 9, 2014, which repurchase cap the Board is inclined to increase over time.  Stock repurchases may be made from time to time, on the open market or through private transactions.  Shares repurchased in this program will be held in treasury for reissue for various corporate purposes, including employee stock option plans.  As of April 29, 2014, a total of 8,093,502 shares had been repurchased under all programs at a cost of $264,264,000.

Commitments_and_Contingent_Lia

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2014
Commitments and Contingent Liabilities	'
Commitments and Contingent Liabilities	'
	Note 10 - Commitments and Contingent Liabilities
	The Company is involved in various legal proceedings that are in various stages of litigation.  Some of these actions allege “lender liability” claims on a variety of theories and claim substantial actual and punitive damages.  The Company has determined, based on discussions with its counsel that any material loss in such actions, individually or in the aggregate, is remote or the damages sought, even if fully recovered, would not be considered material to the consolidated financial position or results of operations of the Company.  However, many of these matters are in various stages of proceedings and further developments could cause management to revise its assessment of these matters.

Capital_Ratios

Capital Ratios	3 Months Ended
	Mar. 31, 2014
Capital Ratios	'
Capital Ratios	'
	Note 11 — Capital Ratios
	The Company had a Tier 1 capital to average total asset (leverage) ratio of 11.72% and 11.61%, risk-weighted Tier 1 capital ratio of 19.22% and 19.33% and risk-weighted total capital ratio of 20.24% and 20.36% at March 31, 2014 and December 31, 2013, respectively.  The identified intangibles and goodwill of $284,737,000 as of March 31, 2014, recorded in connection with the acquisitions made by the Company, are deducted from the sum of core capital elements when determining the capital ratios of the Company.  Under applicable regulatory guidelines, the Capital Securities issued by the Trusts qualify as Tier 1 capital up to a maximum of 25% of tier 1 capital on an aggregate basis.  Any amount that exceeds the 25% threshold qualifies as Tier 2 capital.  As of March 31, 2014, the total of $180,416,000 of the Capital Securities outstanding qualified as Tier 1 capital.  The Company actively monitors the regulatory capital ratios to ensure that the Company’s bank subsidiaries are well capitalized under the regulatory framework.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Measurements	'
Assets and liabilities measured at fair value on a recurring basis	'
					Fair Value Measurements at Reporting Date Using
					(Dollars in Thousands)
		Assets/Liabilities			Quoted Prices		Significant Other		Significant
		Measured at Fair			in Active		Observable		Unobservable
		Value			Markets for		Inputs		Inputs
					Identical
					Assets
		March 31, 2014			(Level 1)		(Level 2)		(Level 3)
	Measured on a recurring basis:
	Assets:
	Available for sale securities
	Residential mortgage-backed securities	$	4,932,505		$	—	$	4,905,549	$	26,956
	States and political subdivisions	261,125			—		261,125		—
	Other	28,927			28,927		—		—
		$	5,222,557		$	28,927	$	5,166,674	$	26,956
					Fair Value Measurements at Reporting Date Using
					(Dollars in Thousands)
		Assets/Liabilities			Quoted Prices		Significant Other		Significant
		Measured at			in Active		Observable		Unobservable
		Fair Value			Markets for		Inputs		Inputs
		December 31,			Identical		(Level 2)		(Level 3)
		2013			Assets
					(Level 1)
	Measured on a recurring basis:
	Assets:
	Available for sale securities
	Residential mortgage-backed securities	$	5,027,701		$	—	$	4,999,849	$	27,852
	States and political subdivisions	248,410			—		248,410		—
	Other	28,468			28,468		—		—
		$	5,304,579		$	28,468	$	5,248,259	$	27,852
Reconciliation of activity for mortgage-backed securities on a net basis	'
	The following table presents a reconciliation of activity for such mortgage-backed securities on a net basis (Dollars in Thousands):
	Balance at December 31, 2013	$	27,852
	Principal paydowns	(928		)
	Total unrealized gains included in:
	Other comprehensive loss	122
	Impairment realized	(90		)
	Balance at March 31, 2014	$	26,956
Financial instruments measured at fair value on a non-recurring basis	'
					Fair Value Measurements at Reporting Date
					Using
					(Dollars in Thousands)
		Assets/Liabilities			Quoted		Significant		Significant		Net Provision
		Measured at Fair			Prices in		Other		Unobservable		During
		Value			Active		Observable		Inputs		Three Month
		March 31, 2014			Markets for		Inputs		(Level 3)		Period
					Identical		(Level 2)
					Assets
					(Level 1)
	Measured on a non-recurring basis:
	Assets:
	Impaired loans	$	21,419		$	—	$	—	$	21,419	$	5,208
	Other real estate owned	5,152			—		—		5,152		138
					Fair Value Measurements at Reporting Date
					Using
					(Dollars in Thousands)
		Assets/Liabilities			Quoted		Significant		Significant		Net
		Measured at Fair			Prices in		Other		Unobservable		Provision
		Value			Active		Observable		Inputs		During
		December 31,			Markets for		Inputs		(Level 3)		Twelve Month
		2013			Identical		(Level 2)				Period
					Assets
					(Level 1)
	Measured on a non-recurring basis:
	Assets:
	Impaired loans	$	28,391		$	—	$	—	$	28,391	$	13,229
	Other real estate owned	16,329			—		—		16,329		1,204

Loans_Tables

Loans (Tables)	3 Months Ended
	Mar. 31, 2014
Loans	'
Summary of loans, by loan type	'
		March 31,		December 31,
		2014		2013
		(Dollars in Thousands)
	Commercial, financial and agricultural	$	2,924,592	$	2,894,779
	Real estate — mortgage	840,165		847,692
	Real estate — construction	1,279,003		1,208,508
	Consumer	63,430		66,414
	Foreign	179,310		181,842
	Total loans	$	5,286,500	$	5,199,235

Allowance_for_Probable_Loan_Lo1

Allowance for Probable Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2014
Allowance for Probable Loan Losses	'
Summary of the transactions in the allowance for probable loan losses by loan class	'
		Three Months Ended March 31, 2014
		Domestic																					Foreign
		Commercial			Commercial			Commercial			Commercial			Residential:			Residential:			Consumer			Foreign			Total
					real estate:			real estate:			real estate:			first lien			junior lien
					other			farmland &			multifamily
					construction &			commercial
					land
					development
		(Dollars in Thousands)
	Balance at December 31, 2013	$	22,433		$	12,541		$	24,467		$	776		$	3,812		$	4,249		$	750		$	1,133		$	70,161
	Losses charge to allowance	(2,481		)	—			—			—			(27		)	(146		)	(187		)	(3		)	(2,844		)
	Recoveries credited to allowance	796			31			23			—			4			33			80			46			1,013
	Net losses charged to allowance	(1,685		)	31			23			—			(23		)	(113		)	(107		)	43			(1,831		)
	Provision charged to operations	7,175			903			(5,556		)	43			(265		)	(168		)	105			(159		)	2,078
	Balance at March 31, 2014	$	27,923		$	13,475		$	18,934		$	819		$	3,524		$	3,968		$	748		$	1,017		$	70,408
		Three Months Ended March 31, 2013
		Domestic																					Foreign
		Commercial			Commercial			Commercial			Commercial			Residential:			Residential:			Consumer			Foreign			Total
					real estate:			real estate:			real estate:			first lien			junior lien
					other			farmland &			multifamily
					construction &			commercial
					land
					development
		(Dollars in Thousands)
	Balance at December 31, 2012	$	11,632		$	12,720		$	21,880		$	694		$	4,390		$	4,448		$	1,289		$	1,140		$	58,193
	Losses charge to allowance	(2,663		)	(128		)	(60		)	—			(172		)	(255		)	(211		)	(20		)	(3,509		)
	Recoveries credited to allowance	694			13			13			—			5			94			46			—			865
	Net losses charged to allowance	(1,969		)	(115		)	(47		)	—			(167		)	(161		)	(165		)	(20		)	(2,644		)
	Provision charged to operations	11,263			(1,552		)	(1,182		)	(85		)	(355		)	(276		)	(304		)	(90		)	7,419
	Balance at March 31, 2013	$	20,926		$	11,053		$	20,651		$	609		$	3,868		$	4,011		$	820		$	1,030		$	62,968
Loans individually or collectively evaluated for impairment and related allowance, by loan class	'
		March 31, 2014
		Loans individually evaluated						Loans collectively evaluated
		for impairment						for impairment
		Recorded			Allowance			Recorded			Allowance
		Investment						Investment
		(Dollars in Thousands)
	Domestic
	Commercial	$	35,539		$	17,424		$	1,059,024		$	10,499
	Commercial real estate: other construction & land development	13,558			852			1,265,445			12,623
	Commercial real estate: farmland & commercial	15,607			2,666			1,706,316			16,268
	Commercial real estate: multifamily	280			—			107,826			819
	Residential: first lien	6,273			—			414,736			3,524
	Residential: junior lien	3,123			—			416,033			3,968
	Consumer	1,453			—			61,977			748
	Foreign	430			—			178,880			1,017
	Total	$	76,263		$	20,942		$	5,210,237		$	49,466
		December 31, 2013
		Loans individually evaluated						Loans collectively evaluated
		for impairment						for impairment
		Recorded			Allowance			Recorded			Allowance
		Investment						Investment
		(Dollars in Thousands)
	Domestic
	Commercial	$	34,183		$	12,234		$	1,008,459		$	10,199
	Commercial real estate: other construction & land development	13,976			852			1,194,532			11,689
	Commercial real estate: farmland & commercial	16,038			2,916			1,734,001			21,551
	Commercial real estate: multifamily	295			—			101,803			776
	Residential: first lien	6,153			—			432,309			3,812
	Residential: junior lien	3,206			—			406,024			4,249
	Consumer	1,606			—			64,808			750
	Foreign	436			—			181,406			1,133
	Total	$	75,893		$	16,002		$	5,123,342		$	54,159
Loans accounted on non-accrual basis, by loan class	'
		March 31, 2014			December 31, 2013
		(Dollars in Thousands)
	Domestic
	Commercial	$	35,476		$	34,110
	Commercial real estate: other construction & land development	11,307			11,726
	Commercial real estate: farmland & commercial	13,344			13,775
	Commercial real estate: multifamily	280			295
	Residential: first lien	1,259			1,266
	Residential: junior lien	1,555			1,576
	Consumer	45			75
	Total non-accrual loans	$	63,266		$	62,823
Impaired loans, by loan class	'
		March 31, 2014
		Recorded			Unpaid			Related			Average			Interest
		Investment			Principal			Allowance			Recorded			Recognized
					Balance						Investment
		(Dollars in Thousands)
	Loans with Related Allowance
	Domestic
	Commercial	$	17,684		$	17,674		$	17,424		$	17,287		$	—
	Commercial real estate: other construction & land development	6,898			6,906			852			6,898			—
	Commercial real estate: farmland & commercial	6,615			6,963			2,666			6,624			23
	Total impaired loans with related allowance	$	31,197		$	31,553		$	20,942		$	30,809		$	23
		March 31, 2014
		Recorded			Unpaid Principal			Average			Interest
		Investment			Balance			Recorded			Recognized
								Investment
		(Dollars in Thousands)
	Loans with No Related Allowance
	Domestic
	Commercial	$	17,855		$	17,876		$	17,060		$	1
	Commercial real estate: other construction & land development	6,660			6,704			6,801			18
	Commercial real estate: farmland & commercial	8,992			10,310			8,656			—
	Commercial real estate: multifamily	280			280			285			—
	Residential: first lien	6,273			6,337			6,287			63
	Residential: junior lien	3,123			3,142			3,133			24
	Consumer	1,453			1,460			1,444			1
	Foreign	430			430			432			5
	Total impaired loans with no related allowance	$	45,066		$	46,539		$	44,098		$	112
		December 31, 2013
		Recorded			Unpaid			Related			Average			Interest
		Investment			Principal			Allowance			Recorded			Recognized
					Balance						Investment
		(Dollars in Thousands)
	Loans with Related Allowance
	Domestic
	Commercial	$	17,178		$	17,177		$	12,234		$	18,019		$	38
	Commercial real estate: other construction & land development	6,818			6,825			852			6,058			—
	Commercial real estate: farmland & commercial	7,259			10,697			2,916			7,167			92
	Total impaired loans with related allowance	$	31,255		$	34,699		$	16,002		$	31,244		$	130
		December 31, 2013
		Recorded			Unpaid Principal			Average			Interest
		Investment			Balance			Recorded			Recognized
								Investment
		(Dollars in Thousands)
	Loans with No Related Allowance
	Domestic
	Commercial	$	17,005		$	17,023		$	16,778		$	2
	Commercial real estate: other construction & land development	7,158			7,187			18,164			74
	Commercial real estate: farmland & commercial	8,779			9,949			7,313			—
	Commercial real estate: multifamily	295			295			322			—
	Residential: first lien	6,153			6,258			4,860			179
	Residential: junior lien	3,206			3,226			2,347			99
	Consumer	1,606			1,612			1,380			1
	Foreign	436			436			452			19
	Total impaired loans with no related allowance	$	44,638		$	45,986		$	51,616		$	374
Information regarding the aging of past due loans, by loan class	'
		March 31, 2014
		30 – 59			60 – 89			90			90 Days			Total			Current			Total
		Days			Days			Days or			or			Past						Portfolio
								Greater			greater			due
											& still
											accruing
		(Dollars in Thousands)
	Domestic
	Commercial	$	4,622		$	1,477		$	35,819		$	2,225		$	41,918		$	1,052,645		$	1,094,563
	Commercial real estate: other construction & land development	642			309			10,537			68			11,488			1,267,515			1,279,003
	Commercial real estate: farmland & commercial	4,988			2,861			7,327			1,099			15,176			1,706,747			1,721,923
	Commercial real estate: multifamily	343			217			280			—			840			107,266			108,106
	Residential: first lien	5,211			1,005			2,613			1,588			8,829			412,180			421,009
	Residential: junior lien	855			96			1,708			183			2,659			416,497			419,156
	Consumer	1,119			489			884			842			2,492			60,938			63,430
	Foreign	2,016			10			329			329			2,355			176,955			179,310
	Total past due loans	$	19,796		$	6,464		$	59,497		$	6,334		$	85,757		$	5,200,743		$	5,286,500
		December 31, 2013
		30 – 59			60 – 89			90 Days or			90 Days			Total			Current			Total
		Days			Days			Greater			or			Past						Portfolio
											greater			due
											& still
											accruing
		(Dollars in Thousands)
	Domestic
	Commercial	$	4,240		$	538		$	36,066		$	2,051		$	40,844		$	1,001,798		$	1,042,642
	Commercial real estate: other construction & land development	1,042			—			9,942			62			10,984			1,197,524			1,208,508
	Commercial real estate: farmland & commercial	6,216			520			6,990			417			13,726			1,736,313			1,750,039
	Commercial real estate: multifamily	39			142			295			—			476			101,622			102,098
	Residential: first lien	4,758			3,046			4,541			3,518			12,345			426,117			438,462
	Residential: junior lien	606			198			1,900			368			2,704			406,526			409,230
	Consumer	1,523			469			803			781			2,795			63,619			66,414
	Foreign	1,467			417			—			—			1,884			179,958			181,842
	Total past due loans	$	19,891		$	5,330		$	60,537		$	7,197		$	85,758		$	5,113,477		$	5,199,235
Summary of the loan portfolio by credit quality indicator, by loan class	'
					March 31, 2014
		Pass			Special			Watch List			Watch List -			Watch List -
					Review			- Pass			Substandard			Impaired
					(Dollars in Thousands)
	Domestic
	Commercial	$	1,001,514		$	7,213		$	4,887		$	45,410		$	35,539
	Commercial real estate: other construction & land development	1,242,189			6,296			8,577			8,383			13,558
	Commercial real estate: farmland & commercial	1,608,212			61,709			22,371			14,024			15,607
	Commercial real estate: multifamily	106,984			—			—			842			280
	Residential: first lien	414,523			118			—			95			6,273
	Residential: junior lien	415,575			—			—			458			3,123
	Consumer	61,977			—			—			—			1,453
	Foreign	178,542			—			—			338			430
	Total	$	5,029,516		$	75,336		$	35,835		$	69,550		$	76,263
					December 31, 2013
		Pass			Special			Watch List			Watch List -			Watch List -
					Review			- Pass			Substandard			Impaired
					(Dollars in Thousands)
	Domestic
	Commercial	$	955,522		$	2,270		$	4,389		$	46,278		$	34,183
	Commercial real estate: other construction & land development	1,167,295			14,247			9,318			3,672			13,976
	Commercial real estate: farmland & commercial	1,635,179			56,438			21,912			20,472			16,038
	Commercial real estate: multifamily	100,948			—			—			855			295
	Residential: first lien	432,067			122			—			120			6,153
	Residential: junior lien	405,731			—			—			293			3,206
	Consumer	64,808			—			—			—			1,606
	Foreign	180,837			—			—			569			436
	Total	$	4,942,387		$	73,077		$	35,619		$	72,259		$	75,893

Stock_Options_Tables

Stock Options (Tables)	3 Months Ended
	Mar. 31, 2014
Stock Options	'
Summary of option activity under stock option plan	'
		Number of	Weighted		Weighted	Aggregate
		options	average		average	intrinsic
			exercise price		remaining	value ($)
					contractual term
					(years)
						(Dollars in Thousands)
	Options outstanding at December 31, 2013	515,143	$	15.98
	Plus: Options granted	549,750	21.42
	Less:
	Options exercised	8,399	14.23
	Options expired	—	—
	Options forfeited	500	10.4
	Options outstanding at March 31, 2014	1,055,994	18.83		6	6,711
	Options fully vested and exercisable at March 31, 2014	222,942	18.43		2.42	1,593

Investment_Securities_Tables

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2014
Investment Securities	'
Amortized cost and estimated fair value by type of investment security	'
	The amortized cost and estimated fair value by type of investment security at March 31, 2014 are as follows:
		Held to Maturity
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value
				Gains			Losses
		(Dollars in Thousands)
	Other securities	$	2,400	$	—		$	—		$	2,400		$	2,400
	Total investment securities	$	2,400	$	—		$	—		$	2,400		$	2,400
		Available for Sale
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value (1)
				Gains			Losses
		(Dollars in Thousands)
	Residential mortgage-backed securities	$	4,976,280	$	52,022		$	(95,797	)	$	4,932,505		$	4,932,505
	Obligations of states and political subdivisions	255,085		12,780			(6,740		)	261,125			261,125
	Equity securities	28,075		1,243			(391		)	28,927			28,927
	Total investment securities	$	5,259,440	$	66,045		$	(102,928	)	$	5,222,557		$	5,222,557
	(1)         Included in the carrying value of residential mortgage-backed securities are $ 1,639,116,000 of mortgage-backed securities issued by Ginnie Mae, $3,266,433,000, of mortgage-backed securities issued by Fannie Mae and Freddie Mac and $26,956,000 issued by non-government entities
	The amortized cost and estimated fair value by type of investment security at December 31, 2013 are as follows:
		Held to Maturity
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value
				Gains			Losses
		(Dollars in Thousands)
	Other securities	$	2,400	$	—		$	—		$	2,400		$	2,400
	Total investment securities	$	2,400	$	—		$	—		$	2,400		$	2,400
		Available for Sale
		Amortized		Gross			Gross			Estimated			Carrying
		Cost		Unrealized			Unrealized			Fair Value			Value (1)
				Gains			Losses
		(Dollars in Thousands)
	Residential mortgage-backed securities	$	5,096,165	$	56,110		$	(124,574	)	$	5,027,701		$	5,027,701
	Obligations of states and political subdivisions	248,354		8,063			(8,007		)	248,410			248,410
	Equity securities	28,075		931			(538		)	28,468			28,468
	Total investment securities	$	5,372,594	$	65,104		$	(133,119	)	$	5,304,579		$	5,304,579
	(1)         Included in the carrying value of residential mortgage-backed securities are $1,799,807 of mortgage-backed securities issued by Ginnie Mae, $3,200,042 of mortgage-backed securities issued by Fannie Mae and Freddie Mac and $27,852 issued by non-government entities
Amortized cost and fair value of investment securities, by contractual maturity	'
	The amortized cost and estimated fair value of investment securities at March 31, 2014, by contractual maturity, are shown below.  Expected maturities will differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties.
		Held to Maturity					Available for Sale
		Amortized		Estimated			Amortized			Estimated
		Cost		Fair Value			Cost			Fair Value
		(Dollars in Thousands)
	Due in one year or less	$	1,200	$	1,200		$	—		$	—
	Due after one year through five years	1,200		1,200			—			—
	Due after five years through ten years	—		—			712			777
	Due after ten years	—		—			254,373			260,348
	Residential mortgage-backed securities	—		—			4,976,280			4,932,505
	Equity securities	—		—			28,075			28,927
	Total investment securities	$	2,400	$	2,400		$	5,259,440		$	5,222,557
Gross unrealized losses on investment securities and the related fair value	'
	Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at March 31, 2014, were as follows:
		Less than 12 Months					12 Months or More						Total
		Fair Value		Unrealized			Fair Value			Unrealized			Fair Value		Unrealized
				Losses						Losses					Losses
		(Dollars in Thousands)
	Available for sale:
	Residential mortgage-backed securities	$	1,028,459	$	(22,666	)	$	1,747,859		$	(73,131	)	$	2,776,318	$	(95,797	)
	Obligations of states and political subdivisions	35,096		(1,166		)	22,377			(5,574		)	57,473		(6,740		)
	Other equity securities	14,816		(184		)	4,042			(207		)	18,858		(391		)
		$	1,078,371	$	(24,016	)	$	1,774,278		$	(78,912	)	$	2,852,649	$	(102,928	)
	Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2013 were as follows:
		Less than 12 Months					12 Months or More						Total
		Fair Value		Unrealized			Fair Value			Unrealized			Fair Value		Unrealized
				Losses						Losses					Losses
		(Dollars in Thousands)
	Available for sale:
	Residential mortgage-backed securities	$	2,459,565	$	(98,022	)	$	420,262		$	(26,552	)	$	2,879,827	$	(124,574	)
	Obligations of states and political subdivisions	55,327		(3,025		)	14,292			(4,982		)	69,619		(8,007		)
	Equity securities	19,462		(538		)	—			—			19,462		(538		)
		$	2,534,354	$	(101,585	)	$	434,554		$	(31,534	)	$	2,968,908	$	(133,119	)
Reconciliation of credit-related impairment charges on available-for-sale investment	'
	The following table presents a reconciliation of credit-related impairment charges on available-for-sale investments recognized in earnings for the three months ended March 31, 2014 and 2013, respectively (Dollars in Thousands):
	Balance at December 31, 2013	$	11,806
	Impairment charges recognized in earnings during period	90
	Balance at March 31, 2014	$	11,896
	Balance at December 31, 2012	$	10,432
	Impairment charges recognized in earnings during period	310
	Balance at March 31, 2013	$	10,742

Junior_Subordinated_Interest_D1

Junior Subordinated Interest Deferrable Debentures (Tables)	3 Months Ended
	Mar. 31, 2014
Junior Subordinated Interest Deferrable Debentures	'
Junior subordinated deferrable interest debentures, major types of business trusts	'
	The following table illustrates key information about each of the Capital and Common Securities and their interest rate at March 31, 2014:
		Junior		Repricing	Interest Rate		Interest Rate	Maturity Date	Optional
		Subordinated		Frequency			Index		Redemption
		Deferrable							Date(1)
		Interest
		Debentures
		(Dollars in Thousands)
	Trust VI	$	25,774	Quarterly	3.69	%	LIBOR + 3.45	November 2032	February 2008
	Trust VIII	25,774		Quarterly	3.29	%	LIBOR + 3.05	October 2033	October 2008
	Trust IX	41,238		Quarterly	1.87	%	LIBOR + 1.62	October 2036	October 2011
	Trust X	34,021		Quarterly	1.89	%	LIBOR + 1.65	February 2037	February 2012
	Trust XI	32,990		Quarterly	1.87	%	LIBOR + 1.62	July 2037	July 2012
	Trust XII	20,619		Quarterly	1.69	%	LIBOR + 1.45	September 2037	September 2012
		$	180,416
	(1)         The Capital Securities may be redeemed in whole or in part on any interest payment date after the Optional Redemption Date.

Basis_of_Presentation_Details

Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2014
	item
Basis of Presentation	'
Number of operating segments	1
Number of active operating bank subsidiaries	4

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Assets:	'	'
Available for sale securities	$5,222,557,000	$5,304,579,000
Assets/Liabilities Measured at Fair Value	'	'
Assets:	'	'
Available for sale securities	5,222,557,000	'
Measured on a recurring basis: | Assets/Liabilities Measured at Fair Value	'	'
Assets:	'	'
Available for sale securities	5,222,557,000	5,304,579,000
Measured on a recurring basis: | Assets/Liabilities Measured at Fair Value | Residential mortgage-backed securities	'	'
Assets:	'	'
Available for sale securities	4,932,505,000	5,027,701,000
Measured on a recurring basis: | Assets/Liabilities Measured at Fair Value | States and political subdivisions	'	'
Assets:	'	'
Available for sale securities	261,125,000	248,410,000
Measured on a recurring basis: | Assets/Liabilities Measured at Fair Value | Other	'	'
Assets:	'	'
Available for sale securities	28,927,000	28,468,000
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets (Level 1)	'	'
Assets:	'	'
Available for sale securities	28,927,000	28,468,000
Measured on a recurring basis: | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other	'	'
Assets:	'	'
Available for sale securities	28,927,000	28,468,000
Measured on a recurring basis: | Significant Other Observable Inputs (Level 2)	'	'
Assets:	'	'
Available for sale securities	5,166,674,000	5,248,259,000
Measured on a recurring basis: | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities	'	'
Assets:	'	'
Available for sale securities	4,905,549,000	4,999,849,000
Measured on a recurring basis: | Significant Other Observable Inputs (Level 2) | States and political subdivisions	'	'
Assets:	'	'
Available for sale securities	261,125,000	248,410,000
Measured on a recurring basis: | Significant Unobservable Inputs (Level 3)	'	'
Assets:	'	'
Available for sale securities	26,956,000	27,852,000
Measured on a recurring basis: | Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities	'	'
Assets:	'	'
Available for sale securities	$26,956,000	$27,852,000

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (Residential mortgage-backed securities, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Residential mortgage-backed securities	'
Reconciliation of activity for mortgage-backed securities on a net basis	'
Balance at the beginning of the period	$27,852
Principal paydowns	-928
Total unrealized gains included in:	'
Other comprehensive loss	122
Impairment realized	-90
Balance at the end of the period	$26,956

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 3) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Assets:	'	'
Impaired Loans	$65,436,000	$64,585,000
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3	'	'
Charges to allowance for probable loan losses in connection with other real estate owned	37,000	402,000
Adjustment to fair value in connection with other real estate owned	138,000	1,204,000
Impaired commercial collateral dependent loans	65,436,000	64,585,000
Impaired commercial collateral dependent receivables appraisals to determine fair value within immediately preceding twelve months	43,571,000	50,346,000
Significant Unobservable Inputs (Level 3) | Bond meeting the original contract terms	'	'
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3	'	'
Minimum period of residential mortgage loan performance under original contract terms	'24 months	'24 months
Estimated future principal prepayment rate assumption, low end of range (as a percent)	7.00%	7.00%
Default rate assumptions (as a percent)	1.00%	1.00%
Loss severity rate assumptions, first year (as a percent)	25.00%	25.00%
Estimated future principal prepayment rate assumption, discount rate (as a percent)	13.00%	13.00%
Significant Unobservable Inputs (Level 3) | Bond not meeting the original contract terms	'	'
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3	'	'
Estimated future principal prepayment rate assumption, low end of range (as a percent)	2.00%	2.00%
Default rate assumptions (as a percent)	4.50%	4.50%
Loss severity rate assumptions, first year (as a percent)	60.00%	60.00%
Decrease in loss severity rates, following five years (as a percent)	5.00%	5.00%
Loss severity rate, thereafter (as a percent)	25.00%	25.00%
Estimated future principal prepayment rate assumption, discount rate (as a percent)	13.00%	13.00%
Measured on a non-recurring basis:	'	'
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3	'	'
Change in net provision, impaired loans	5,208,000	13,229,000
Change in net provision, other real estate owned	138,000	1,204,000
Measured on a non-recurring basis: | Assets/Liabilities Measured at Fair Value	'	'
Assets:	'	'
Impaired Loans	21,419,000	28,391,000
Non-financial assets:	'	'
Other real estate owned	5,152,000	16,329,000
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3	'	'
Impaired commercial collateral dependent loans	21,419,000	28,391,000
Measured on a non-recurring basis: | Significant Unobservable Inputs (Level 3)	'	'
Assets:	'	'
Impaired Loans	21,419,000	28,391,000
Non-financial assets:	'	'
Other real estate owned	5,152,000	16,329,000
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3	'	'
Impaired commercial collateral dependent loans	$21,419,000	$28,391,000

Fair_Value_Measurements_Detail3

Fair Value Measurements (Details 4) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Deposits	'	'
Carrying amount of time deposits	$2,640,186,000	$2,651,303,000
Significant Other Observable Inputs (Level 2)	'	'
Other borrowed funds	'	'
Carrying amount of the long-term FHLB borrowings	8,903,000	8,951,000
Estimated fair value of long-term FHLB borrowings	8,911,000	8,950,000
Significant Unobservable Inputs (Level 3)	'	'
Loans	'	'
Carrying amount of fixed rate performing loans	1,254,640,000	1,243,252,000
Estimated fair value of fixed rate performing loans	1,206,449,000	1,196,916,000
Deposits	'	'
Carrying amount of time deposits	2,640,186,000	2,651,303,000
Estimated fair value of time deposits	2,638,519,000	2,648,452,000
Securities Sold Under Repurchase Agreements	'	'
Carrying amount of long-term repurchase agreements	610,000,000	710,000,000
Estimated fair value of long-term repurchase agreements	$674,938,000	$792,215,500

Loans_Details

Loans (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Summary of loans, by loan type	'	'
Total loans	$5,286,500	$5,199,235
Commercial, financial and agricultural	'	'
Summary of loans, by loan type	'	'
Total loans	2,924,592	2,894,779
Real estate - mortgage	'	'
Summary of loans, by loan type	'	'
Total loans	840,165	847,692
Real estate - construction	'	'
Summary of loans, by loan type	'	'
Total loans	1,279,003	1,208,508
Consumer	'	'
Summary of loans, by loan type	'	'
Total loans	63,430	66,414
Foreign	'	'
Summary of loans, by loan type	'	'
Total loans	$179,310	$181,842

Allowance_for_Probable_Loan_Lo2

Allowance for Probable Loan Losses (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Allowance for probable loan losses	'	'
Balance at the beginning of the period	$70,161	$58,193
Losses charged to allowance	-2,844	-3,509
Recoveries credited to allowance	1,013	865
Net losses charged to allowance	-1,831	-2,644
Provision charged to operations	2,078	7,419
Balance at the end of the period	70,408	62,968
Commercial	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	22,433	11,632
Losses charged to allowance	-2,481	-2,663
Recoveries credited to allowance	796	694
Net losses charged to allowance	-1,685	-1,969
Provision charged to operations	7,175	11,263
Balance at the end of the period	27,923	20,926
Commercial real estate: other construction and land development	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	12,541	12,720
Losses charged to allowance	'	-128
Recoveries credited to allowance	31	13
Net losses charged to allowance	31	-115
Provision charged to operations	903	-1,552
Balance at the end of the period	13,475	11,053
Commercial real estate: farmland and commercial	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	24,467	21,880
Losses charged to allowance	'	-60
Recoveries credited to allowance	23	13
Net losses charged to allowance	23	-47
Provision charged to operations	-5,556	-1,182
Balance at the end of the period	18,934	20,651
Commercial real estate: multifamily	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	776	694
Provision charged to operations	43	-85
Balance at the end of the period	819	609
Residential: first lien	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	3,812	4,390
Losses charged to allowance	-27	-172
Recoveries credited to allowance	4	5
Net losses charged to allowance	-23	-167
Provision charged to operations	-265	-355
Balance at the end of the period	3,524	3,868
Residential: junior lien	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	4,249	4,448
Losses charged to allowance	-146	-255
Recoveries credited to allowance	33	94
Net losses charged to allowance	-113	-161
Provision charged to operations	-168	-276
Balance at the end of the period	3,968	4,011
Consumer	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	750	1,289
Losses charged to allowance	-187	-211
Recoveries credited to allowance	80	46
Net losses charged to allowance	-107	-165
Provision charged to operations	105	-304
Balance at the end of the period	748	820
Foreign	'	'
Allowance for probable loan losses	'	'
Balance at the beginning of the period	1,133	1,140
Losses charged to allowance	-3	-20
Recoveries credited to allowance	46	'
Net losses charged to allowance	43	-20
Provision charged to operations	-159	-90
Balance at the end of the period	$1,017	$1,030

Allowance_for_Probable_Loan_Lo3

Allowance for Probable Loan Losses (Details 2) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	$76,263	$75,893
Loans individually evaluated for impairment, Allowance	20,942	16,002
Loans collectively evaluated for impairment, Recorded Investment	5,210,237	5,123,342
Loans collectively evaluated for impairment, Allowance	49,466	54,159
Commercial	'	'
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	35,539	34,183
Loans individually evaluated for impairment, Allowance	17,424	12,234
Loans collectively evaluated for impairment, Recorded Investment	1,059,024	1,008,459
Loans collectively evaluated for impairment, Allowance	10,499	10,199
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	13,558	13,976
Loans individually evaluated for impairment, Allowance	852	852
Loans collectively evaluated for impairment, Recorded Investment	1,265,445	1,194,532
Loans collectively evaluated for impairment, Allowance	12,623	11,689
Commercial real estate: farmland and commercial	'	'
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	15,607	16,038
Loans individually evaluated for impairment, Allowance	2,666	2,916
Loans collectively evaluated for impairment, Recorded Investment	1,706,316	1,734,001
Loans collectively evaluated for impairment, Allowance	16,268	21,551
Commercial real estate: multifamily	'	'
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	280	295
Loans collectively evaluated for impairment, Recorded Investment	107,826	101,803
Loans collectively evaluated for impairment, Allowance	819	776
Residential: first lien	'	'
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	6,273	6,153
Loans collectively evaluated for impairment, Recorded Investment	414,736	432,309
Loans collectively evaluated for impairment, Allowance	3,524	3,812
Residential: junior lien	'	'
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	3,123	3,206
Loans collectively evaluated for impairment, Recorded Investment	416,033	406,024
Loans collectively evaluated for impairment, Allowance	3,968	4,249
Consumer	'	'
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	1,453	1,606
Loans collectively evaluated for impairment, Recorded Investment	61,977	64,808
Loans collectively evaluated for impairment, Allowance	748	750
Foreign	'	'
Loan loss allowances, impaired financing receivable, evaluated individually or collectively	'	'
Loans individually evaluated for impairment, Recorded Investment	430	436
Loans collectively evaluated for impairment, Recorded Investment	178,880	181,406
Loans collectively evaluated for impairment, Allowance	$1,017	$1,133

Allowance_for_Probable_Loan_Lo4

Allowance for Probable Loan Losses (Details 3) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	$63,266	$62,823
Commercial	'	'
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	35,476	34,110
Commercial real estate: other construction and land development	'	'
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	11,307	11,726
Commercial real estate: farmland and commercial	'	'
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	13,344	13,775
Commercial real estate: multifamily	'	'
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	280	295
Residential: first lien	'	'
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	1,259	1,266
Residential: junior lien	'	'
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	1,555	1,576
Consumer	'	'
Loan loss allowances, financing receivable past due	'	'
Non-accrual loans, total	$45	$75

Allowance_for_Probable_Loan_Lo5

Allowance for Probable Loan Losses (Details 4) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Interest Recognized	'	'
Loans accounted for as troubled debt restructuring	$19,148,000	$20,358,000
Period of charge off for past due unsecured commercial loans	'90 days	'
Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with related allowance	31,197,000	31,255,000
Total impaired loans with no related allowance	45,066,000	44,638,000
Unpaid principal balance:	'	'
Total impaired loans with an allowance recorded	31,553,000	34,699,000
Total impaired loans with no related allowance recorded	46,539,000	45,986,000
Related Allowance	20,942,000	16,002,000
Average recorded investment:	'	'
Total impaired loans with an allowance recorded	30,809,000	31,244,000
Total impaired loans with no related allowance recorded	44,098,000	51,616,000
Interest Recognized	'	'
Total impaired loans with an allowance recorded	23,000	130,000
Total impaired loans with no related allowance recorded	112,000	374,000
Commercial | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with related allowance	17,684,000	17,178,000
Total impaired loans with no related allowance	17,855,000	17,005,000
Unpaid principal balance:	'	'
Total impaired loans with an allowance recorded	17,674,000	17,177,000
Total impaired loans with no related allowance recorded	17,876,000	17,023,000
Related Allowance	17,424,000	12,234,000
Average recorded investment:	'	'
Total impaired loans with an allowance recorded	17,287,000	18,019,000
Total impaired loans with no related allowance recorded	17,060,000	16,778,000
Interest Recognized	'	'
Total impaired loans with an allowance recorded	'	38,000
Total impaired loans with no related allowance recorded	1,000	2,000
Commercial real estate: other construction and land development | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with related allowance	6,898,000	6,818,000
Total impaired loans with no related allowance	6,660,000	7,158,000
Unpaid principal balance:	'	'
Total impaired loans with an allowance recorded	6,906,000	6,825,000
Total impaired loans with no related allowance recorded	6,704,000	7,187,000
Related Allowance	852,000	852,000
Average recorded investment:	'	'
Total impaired loans with an allowance recorded	6,898,000	6,058,000
Total impaired loans with no related allowance recorded	6,801,000	18,164,000
Interest Recognized	'	'
Total impaired loans with no related allowance recorded	18,000	74,000
Commercial real estate: farmland and commercial | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with related allowance	6,615,000	7,259,000
Total impaired loans with no related allowance	8,992,000	8,779,000
Unpaid principal balance:	'	'
Total impaired loans with an allowance recorded	6,963,000	10,697,000
Total impaired loans with no related allowance recorded	10,310,000	9,949,000
Related Allowance	2,666,000	2,916,000
Average recorded investment:	'	'
Total impaired loans with an allowance recorded	6,624,000	7,167,000
Total impaired loans with no related allowance recorded	8,656,000	7,313,000
Interest Recognized	'	'
Total impaired loans with an allowance recorded	23,000	92,000
Commercial real estate: multifamily | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with no related allowance	280,000	295,000
Unpaid principal balance:	'	'
Total impaired loans with no related allowance recorded	280,000	295,000
Average recorded investment:	'	'
Total impaired loans with no related allowance recorded	285,000	322,000
Residential: first lien | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with no related allowance	6,273,000	6,153,000
Unpaid principal balance:	'	'
Total impaired loans with no related allowance recorded	6,337,000	6,258,000
Average recorded investment:	'	'
Total impaired loans with no related allowance recorded	6,287,000	4,860,000
Interest Recognized	'	'
Total impaired loans with no related allowance recorded	63,000	179,000
Residential: junior lien | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with no related allowance	3,123,000	3,206,000
Unpaid principal balance:	'	'
Total impaired loans with no related allowance recorded	3,142,000	3,226,000
Average recorded investment:	'	'
Total impaired loans with no related allowance recorded	3,133,000	2,347,000
Interest Recognized	'	'
Total impaired loans with no related allowance recorded	24,000	99,000
Consumer | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with no related allowance	1,453,000	1,606,000
Unpaid principal balance:	'	'
Total impaired loans with no related allowance recorded	1,460,000	1,612,000
Average recorded investment:	'	'
Total impaired loans with no related allowance recorded	1,444,000	1,380,000
Interest Recognized	'	'
Total impaired loans with no related allowance recorded	1,000	1,000
Foreign | Class of financing receivable	'	'
Recorded investment:	'	'
Total impaired loans with no related allowance	430,000	436,000
Unpaid principal balance:	'	'
Total impaired loans with no related allowance recorded	430,000	436,000
Average recorded investment:	'	'
Total impaired loans with no related allowance recorded	432,000	452,000
Interest Recognized	'	'
Total impaired loans with no related allowance recorded	$5,000	$19,000

Allowance_for_Probable_Loan_Lo6

Allowance for Probable Loan Losses (Details 5) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing receivable recorded investment	'	'
Past due 30-59 days	$19,796	$19,891
Past due 60-89 days	6,464	5,330
Past due 90 days or greater	59,497	60,537
Past due 90 days or greater and still accruing	6,334	7,197
Past due, total	85,757	85,758
Loans, current	5,200,743	5,113,477
Total loans	5,286,500	5,199,235
Commercial	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	4,622	4,240
Past due 60-89 days	1,477	538
Past due 90 days or greater	35,819	36,066
Past due 90 days or greater and still accruing	2,225	2,051
Past due, total	41,918	40,844
Loans, current	1,052,645	1,001,798
Total loans	1,094,563	1,042,642
Commercial real estate: other construction and land development	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	642	1,042
Past due 60-89 days	309	'
Past due 90 days or greater	10,537	9,942
Past due 90 days or greater and still accruing	68	62
Past due, total	11,488	10,984
Loans, current	1,267,515	1,197,524
Total loans	1,279,003	1,208,508
Commercial real estate: farmland and commercial	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	4,988	6,216
Past due 60-89 days	2,861	520
Past due 90 days or greater	7,327	6,990
Past due 90 days or greater and still accruing	1,099	417
Past due, total	15,176	13,726
Loans, current	1,706,747	1,736,313
Total loans	1,721,923	1,750,039
Commercial real estate: multifamily	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	343	39
Past due 60-89 days	217	142
Past due 90 days or greater	280	295
Past due, total	840	476
Loans, current	107,266	101,622
Total loans	108,106	102,098
Residential: first lien	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	5,211	4,758
Past due 60-89 days	1,005	3,046
Past due 90 days or greater	2,613	4,541
Past due 90 days or greater and still accruing	1,588	3,518
Past due, total	8,829	12,345
Loans, current	412,180	426,117
Total loans	421,009	438,462
Residential: junior lien	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	855	606
Past due 60-89 days	96	198
Past due 90 days or greater	1,708	1,900
Past due 90 days or greater and still accruing	183	368
Past due, total	2,659	2,704
Loans, current	416,497	406,526
Total loans	419,156	409,230
Consumer	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	1,119	1,523
Past due 60-89 days	489	469
Past due 90 days or greater	884	803
Past due 90 days or greater and still accruing	842	781
Past due, total	2,492	2,795
Loans, current	60,938	63,619
Total loans	63,430	66,414
Foreign	'	'
Financing receivable recorded investment	'	'
Past due 30-59 days	2,016	1,467
Past due 60-89 days	10	417
Past due 90 days or greater	329	'
Past due 90 days or greater and still accruing	329	'
Past due, total	2,355	1,884
Loans, current	176,955	179,958
Total loans	$179,310	$181,842

Allowance_for_Probable_Loan_Lo7

Allowance for Probable Loan Losses (Details 6) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Loan portfolio by credit quality indicator	'	'
Portfolio, total	$5,286,500	$5,199,235
Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	5,029,516	4,942,387
Special Review	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	75,336	73,077
Watch List - Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	35,835	35,619
Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	69,550	72,259
Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	76,263	75,893
Commercial	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	1,094,563	1,042,642
Commercial | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	1,001,514	955,522
Commercial | Special Review	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	7,213	2,270
Commercial | Watch List - Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	4,887	4,389
Commercial | Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	45,410	46,278
Commercial | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	35,539	34,183
Commercial real estate: other construction and land development	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	1,279,003	1,208,508
Commercial real estate: other construction and land development | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	1,242,189	1,167,295
Commercial real estate: other construction and land development | Special Review	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	6,296	14,247
Commercial real estate: other construction and land development | Watch List - Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	8,577	9,318
Commercial real estate: other construction and land development | Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	8,383	3,672
Commercial real estate: other construction and land development | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	13,558	13,976
Commercial real estate: farmland and commercial	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	1,721,923	1,750,039
Commercial real estate: farmland and commercial | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	1,608,212	1,635,179
Commercial real estate: farmland and commercial | Special Review	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	61,709	56,438
Commercial real estate: farmland and commercial | Watch List - Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	22,371	21,912
Commercial real estate: farmland and commercial | Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	14,024	20,472
Commercial real estate: farmland and commercial | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	15,607	16,038
Commercial real estate: multifamily	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	108,106	102,098
Commercial real estate: multifamily | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	106,984	100,948
Commercial real estate: multifamily | Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	842	855
Commercial real estate: multifamily | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	280	295
Residential: first lien	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	421,009	438,462
Residential: first lien | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	414,523	432,067
Residential: first lien | Special Review	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	118	122
Residential: first lien | Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	95	120
Residential: first lien | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	6,273	6,153
Residential: junior lien	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	419,156	409,230
Residential: junior lien | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	415,575	405,731
Residential: junior lien | Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	458	293
Residential: junior lien | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	3,123	3,206
Consumer	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	63,430	66,414
Consumer | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	61,977	64,808
Consumer | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	1,453	1,606
Foreign	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	179,310	181,842
Foreign | Pass	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	178,542	180,837
Foreign | Watch List - Substandard	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	338	569
Foreign | Watch List - Impaired	'	'
Loan portfolio by credit quality indicator	'	'
Portfolio, total	$430	$436

Stock_Options_Details

Stock Options (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Apr. 05, 2012
Stock options under 2012 Plan	'	'	'
Stock option details	'	'	'
Shares available for future grants	199,250	'	800,000
Maximum exercisable period for options granted	'10 years	'	'
Stock option activity	'	'	'
Options outstanding at the beginning of the period (in shares)	515,143	'	'
Plus: Options granted (in shares)	549,750	'	'
Less:	'	'	'
Options exercised (in shares)	8,399	'	'
Options forfeited (in shares)	500	'	'
Options outstanding at the end of the period (in shares)	1,055,994	'	'
Options fully vested and exercisable at the end of the period (in shares)	222,942	'	'
Stock options, weighted average exercise price	'	'	'
Options outstanding at the beginning, weighted average exercise price (in dollars per share)	$15.98	'	'
Plus: Options granted, weighted average exercise price (in dollars per share)	$21.42	'	'
Less:	'	'	'
Options exercised, weighted average exercise price (in dollars per share)	$14.23	'	'
Options forfeited, weighted average exercise price (in dollars per share)	$10.40	'	'
Options outstanding at the end, weighted average exercise price (in dollars per share)	$18.83	'	'
Options fully vested and exercisable at the end, weighted average exercise price (in dollars per share)	$18.43	'	'
Stock options, weighted average remaining contractual term	'	'	'
Options outstanding at the end, weighted average remaining contractual term	'6 years	'	'
Options fully vested and exercisable at the end, weighted average remaining contractual term	'2 years 5 months 1 day	'	'
Stock options, aggregate intrinsic value	'	'	'
Options outstanding at the end, aggregate intrinsic value	$6,711,000	'	'
Options fully vested and exercisable at the end, aggregate intrinsic value	1,593,000	'	'
Stock-based compensation expense	161,000	114,000	'
Stock-based compensation cost, unrecognized, related to non-vested options	$4,831,000	'	'
Stock-based compensation cost, unrecognized, related to non-vested options, weighted-average period of recognition	'2 years 7 months 6 days	'	'
Incentive stock options granted to 10% shareholders	'	'	'
Stock option details	'	'	'
Maximum exercisable period for options granted	'5 years	'	'

Investment_Securities_Details

Investment Securities (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Held-to-maturity securities	'	'
Amortized Cost	$2,400,000	$2,400,000
Estimated Fair Value	2,400,000	2,400,000
Carrying Value	2,400,000	2,400,000
Available-for-sale securities	'	'
Amortized Cost	5,259,440,000	5,372,594,000
Gross Unrealized Gains	66,045,000	65,104,000
Gross Unrealized Losses	-102,928,000	-133,119,000
Total investment securities	5,222,557,000	5,304,579,000
Estimated Fair Value	'	'
Available-for-sale securities	'	'
Total investment securities	5,222,557,000	5,304,579,000
Carrying Value	'	'
Available-for-sale securities	'	'
Total investment securities	5,222,557,000	5,304,579,000
Other securities	'	'
Held-to-maturity securities	'	'
Amortized Cost	2,400,000	2,400,000
Estimated Fair Value	2,400,000	2,400,000
Carrying Value	2,400,000	2,400,000
Residential mortgage-backed securities	'	'
Available-for-sale securities	'	'
Amortized Cost	4,976,280,000	5,096,165,000
Gross Unrealized Gains	52,022,000	56,110,000
Gross Unrealized Losses	-95,797,000	-124,574,000
Residential mortgage-backed securities | Estimated Fair Value	'	'
Available-for-sale securities	'	'
Total investment securities	4,932,505,000	5,027,701,000
Residential mortgage-backed securities | Carrying Value	'	'
Available-for-sale securities	'	'
Total investment securities	4,932,505,000	5,027,701,000
Mortgage-backed securities by Ginnie Mae	'	'
Available-for-sale securities	'	'
Total investment securities	1,639,116,000	1,799,807,000
Mortgage-backed securities by Fannie Mae and Freddie Mac	'	'
Available-for-sale securities	'	'
Total investment securities	3,266,433,000	3,200,042,000
Mortgage-backed securities by non-government entities	'	'
Available-for-sale securities	'	'
Total investment securities	26,956,000	27,852,000
Obligations of states and political subdivisions	'	'
Available-for-sale securities	'	'
Amortized Cost	255,085,000	248,354,000
Gross Unrealized Gains	12,780,000	8,063,000
Gross Unrealized Losses	-6,740,000	-8,007,000
Obligations of states and political subdivisions | Estimated Fair Value	'	'
Available-for-sale securities	'	'
Total investment securities	261,125,000	248,410,000
Obligations of states and political subdivisions | Carrying Value	'	'
Available-for-sale securities	'	'
Total investment securities	261,125,000	248,410,000
Equity Securities	'	'
Available-for-sale securities	'	'
Amortized Cost	28,075,000	28,075,000
Gross Unrealized Gains	1,243,000	931,000
Gross Unrealized Losses	-391,000	-538,000
Equity Securities | Estimated Fair Value	'	'
Available-for-sale securities	'	'
Total investment securities	28,927,000	28,468,000
Equity Securities | Carrying Value	'	'
Available-for-sale securities	'	'
Total investment securities	$28,927,000	$28,468,000

Investment_Securities_Details_

Investment Securities (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Held-to-maturity debt securities amortized cost disclosures	'	'	'
Due in one year or less, held-to-maturity debt securities amortized cost	$1,200,000	'	'
Due after one year through five years, held-to-maturity debt securities amortized cost	1,200,000	'	'
Amortized cost, held-to-maturity debt securities	2,400,000	'	2,400,000
Held-to-maturity debt securities, Estimated fair value disclosures	'	'	'
Due in one year or less, held-to-maturity debt securities, Estimated fair value	1,200,000	'	'
Due after one year through five years, held-to-maturity debt securities, Estimated fair value	1,200,000	'	'
Estimated Fair Value	2,400,000	'	2,400,000
Available-for-sale debt securities amortized cost disclosures	'	'	'
Due after five years through ten years, available-for-sale debt securities amortized cost	712,000	'	'
Due after ten years, available-for-sale debt securities amortized cost	254,373,000	'	'
Residential mortgage-backed securities, amortized cost	4,976,280,000	'	'
Equity securities, amortized cost	28,075,000	'	'
Amortized cost, Available for sale securities	5,259,440,000	'	5,372,594,000
Available for sale debt securities, Estimated Fair Value Disclosures	'	'	'
Due after five years through ten years, available-for-sale debt securities, Estimated Fair Value	777,000	'	'
Due after ten years, available-for-sale debt securities, Estimated Fair Value	260,348,000	'	'
Residential mortgage-backed securities, Estimated Fair Value	4,932,505,000	'	'
Equity securities, Estimated Fair Value	28,927,000	'	'
Estimated fair value, Available for sale securities	5,222,557,000	'	5,304,579,000
Amortized cost of available for sale investment securities pledged	2,643,050,000	'	'
Fair value of available for sale investment securities pledged	2,640,974,000	'	'
Proceeds from sales and calls of available for sale securities	258,277,000	178,124,000	'
Proceeds from sales of mortgage-backed securities	257,621,000	177,623,000	'
Gross gains realized on sales	8,108,000	9,601,000	'
Gross losses realized on sales	0	0	'
Impairment charges on available for sale securities	90,000	310,000	'
Impairment charges on available-for-sale investment securities, after tax	$58,500	$201,500	'

Investment_Securities_Details_1

Investment Securities (Details 3) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Available for sale:	'	'
Fair value, less than 12 months	$1,078,371	$2,534,354
Unrealized losses, less than 12 months	-24,016	-101,585
Fair value, 12 months or more	1,774,278	434,554
Unrealized losses, 12 months or more	-78,912	-31,534
Fair value, total	2,852,649	2,968,908
Unrealized losses, total	-102,928	-133,119
Residential mortgage-backed securities	'	'
Available for sale:	'	'
Fair value, less than 12 months	1,028,459	2,459,565
Unrealized losses, less than 12 months	-22,666	-98,022
Fair value, 12 months or more	1,747,859	420,262
Unrealized losses, 12 months or more	-73,131	-26,552
Fair value, total	2,776,318	2,879,827
Unrealized losses, total	-95,797	-124,574
Obligations of states and political subdivisions	'	'
Available for sale:	'	'
Fair value, less than 12 months	35,096	55,327
Unrealized losses, less than 12 months	-1,166	-3,025
Fair value, 12 months or more	22,377	14,292
Unrealized losses, 12 months or more	-5,574	-4,982
Fair value, total	57,473	69,619
Unrealized losses, total	-6,740	-8,007
Equity Securities	'	'
Available for sale:	'	'
Fair value, less than 12 months	14,816	19,462
Unrealized losses, less than 12 months	-184	-538
Fair value, 12 months or more	4,042	'
Unrealized losses, 12 months or more	-207	'
Fair value, total	18,858	19,462
Unrealized losses, total	($391)	($538)

Investment_Securities_Details_2

Investment Securities (Details 4) (Available for sale investments, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Available for sale investments	'	'
Reconciliation of credit-related impairment charges on investments recognized in earnings	'	'
Balance at the beginning	$11,806	$10,432
Impairment charges recognized in earnings during period	90	310
Balance at the end	$11,896	$10,742

Other_Borrowed_Funds_Details

Other Borrowed Funds (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Other Borrowed Funds	'	'
Other borrowed funds	$1,148,403	$1,223,950
Percentage of decrease in other borrowed funds	-6.20%	'

Junior_Subordinated_Interest_D2

Junior Subordinated Interest Deferrable Debentures (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Feb. 11, 2014
	item		IB Capital Trust VII
Junior Subordinated Interest Deferrable Debentures	'	'	'
Number of statutory business trusts issuing trust preferred securities	7	'	'
Junior subordinated deferrable interest debentures	$180,416,000	$190,726,000	'
Junior subordinated deferrable interest debentures, major types of business trusts	'	'	'
Redemption price discount (as a percent)	'	'	6.00%
Retirement of capital securities	'	'	10,310,000
Maximum number of consecutive quarterly period available for deferral of interest payment on Trusts VI, VII, VIII, IX, X, XI and XII	20	'	'
Percentage of capital securities issued by trust qualifying as Tier I capital, maximum	25.00%	'	'
Percentage of capital securities issued by trust qualifying as Tier II capital, minimum	25.00%	'	'
Capital securities issued by the trust, qualifying as Tier I capital	$180,416,000	$190,726,000	'

Junior_Subordinated_Interest_D3

Junior Subordinated Interest Deferrable Debentures (Details 2) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified			Trust VI	Trust VIII	Trust IX	Trust X	Trust XI	Trust XII
Junior subordinated deferrable interest debentures, major types of business trusts	'	'	'	'	'	'	'	'
Junior subordinated deferrable interest debentures	$180,416	$190,726	$25,774	$25,774	$41,238	$34,021	$32,990	$20,619
Interest rate (as a percent)	'	'	3.69%	3.29%	1.87%	1.89%	1.87%	1.69%
Interest rate index	'	'	'LIBOR	'LIBOR	'LIBOR	'LIBOR	'LIBOR	'LIBOR
Spread on interest rate index (as a percent)	'	'	3.45%	3.05%	1.62%	1.65%	1.62%	1.45%

Common_Stock_and_Dividends_Det

Common Stock and Dividends (Details) (USD $)	0 Months Ended					1 Months Ended	3 Months Ended
	Apr. 18, 2014	Apr. 09, 2014	Mar. 07, 2014	Oct. 15, 2013	Apr. 20, 2013	Apr. 30, 2009	Mar. 31, 2014	Apr. 29, 2014
Common Stock and Dividends	'	'	'	'	'	'	'	'
Series A cumulative perpetual preferred shares, outstanding	'	'	'	'	'	'	216,000	'
Warrants to purchase entity's common stock (in shares)	'	'	'	'	'	'	1,326,238	'
Warrants, exercise price (in dollars per share)	'	'	'	'	'	'	$24.43	'
Percentage of aggregate common stock investment on exercise of warrant to Senior Preferred Stock investment	'	'	'	'	'	'	15.00%	'
Warrants, term	'	'	'	'	'	'	'10 years	'
Cash dividends paid to common shareholders (in dollars per share)	$0.25	'	'	$0.23	$0.20	'	'	'
Repurchase of common stock, authorized amount	'	'	$40,000,000	'	'	$40,000,000	'	'
Period of repurchase of common stock	'	'12 months	'	'	'	'12 months	'	'
Cumulative number of shares repurchased under all stock repurchase programs	'	'	'	'	'	'	'	8,093,502
Cumulative cost of shares repurchased under all stock repurchase programs	'	'	'	'	'	'	'	$264,264,000

Capital_Ratios_Details

Capital Ratios (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Capital Ratios	'	'
Tier 1 Capital (to Average Assets), Actual Ratio (as a percent)	11.72%	11.61%
Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	19.22%	19.33%
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	20.24%	20.36%
Identified intangibles and goodwill	$284,737,000	'
Percentage of capital securities issued by trust qualifying as Tier I capital, maximum	25.00%	'
Percentage of capital securities issued by trust qualifying as Tier II capital, minimum	25.00%	'
Capital securities issued by the trust, qualifying as Tier I capital	$180,416,000	$190,726,000