Iberiabank (IBKC) 10-Q 6 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Trading Symbol	IBKC
Entity Registrant Name	IBERIABANK CORP
Entity Central Index Key	933,141
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		41,133,561

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets
Cash and due from banks	$ 370,657	$ 251,994
Interest-bearing deposits in banks	311,615	296,101
Total cash and cash equivalents	682,272	548,095
Securities available for sale, at fair value	2,827,805	2,158,853
Securities held to maturity (fair values of $100,611 and $119,481, respectively)	98,330	116,960
Mortgage loans held for sale ($202,168 and $139,950 recorded at fair value, respectively)	202,168	140,072
Loans covered by loss share agreements	253,541	444,544
Non-covered loans, net of unearned income	13,863,478	10,996,500
Total loans, net of unearned income	14,117,019	11,441,044
Allowance for loan losses	(130,254)	(130,131)
Loans, net	13,986,765	11,310,913
FDIC loss share receivables	43,443	69,627
Premises and equipment, net	333,273	307,159
Goodwill	719,463	517,526
Other assets	640,706	588,699
Total Assets	19,534,225	15,757,904
Deposits:
Non-interest-bearing	4,392,808	3,195,430
Interest-bearing	11,910,257	9,325,095
Total deposits	16,303,065	12,520,525
Short-term borrowings	222,460	845,742
Long-term debt	341,973	403,254
Other liabilities	183,526	136,235
Total Liabilities	17,051,024	13,905,756
Shareholders’ Equity
Preferred stock, $1 par value - 5,000,000 shares authorized	8	0
Common stock, $1 par value - 100,000,000 shares and 50,000,000 shares authorized, respectively; 41,128,766 and 35,262,901 shares issued and outstanding, respectively	41,129	35,263
Additional paid-in capital	1,871,016	1,398,633
Retained earnings	554,065	496,573
Accumulated other comprehensive income	16,983	7,525
Treasury stock at cost - 0 and 1,809,497 shares, respectively	0	(85,846)
Total Shareholders’ Equity	2,483,201	1,852,148
Total Liabilities and Shareholders’ Equity	$ 19,534,225	$ 15,757,904

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Securities held to maturity, fair values	$ 100,611	$ 119,481
Mortgage loans held for sale recorded at fair value	$ 202,168	$ 139,950
Preferred stock, par value (in usd per share)	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Liquidation preference (per share)	$ 10,000	$ 10,000
Preferred stock, shares issued	8,000	0
Preferred stock, shares outstanding	8,000	0
Common stock, par value (in usd per share)	$ 1	$ 1
Common stock, shares authorized	100,000,000	50,000,000
Common stock, shares issued	41,128,766	35,262,901
Common stock, shares outstanding	41,128,766	35,262,901
Treasury stock, shares	0	1,809,497

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest and Dividend Income
Loans, including fees	$ 159,915	$ 145,472	$ 443,441	$ 390,044
Mortgage loans held for sale, including fees	1,847	1,594	4,742	3,953
Investment securities:
Taxable interest	12,184	9,552	33,906	28,411
Tax-exempt interest	1,546	1,442	4,111	4,500
Amortization of FDIC loss share receivable	(5,600)	(25,120)	(19,011)	(61,393)
Other	1,185	853	3,018	2,024
Total interest and dividend income	171,077	133,793	470,207	367,539
Deposits:
NOW and MMDA	7,968	5,046	19,409	13,353
Savings	217	88	525	235
Time deposits	5,039	3,983	14,410	10,009
Short-term borrowings	116	406	699	1,022
Long-term debt	2,620	2,519	8,566	7,488
Total interest expense	15,960	12,042	43,609	32,107
Net interest income	155,117	121,751	426,598	335,432
Provision for loan losses	5,062	5,714	19,197	12,565
Net interest income after provision for loan losses	150,055	116,037	407,401	322,867
Non-interest Income
Mortgage income	20,730	14,263	63,999	38,150
Service charges on deposit accounts	11,342	10,205	30,766	25,421
Title revenue	6,627	5,577	17,402	15,007
ATM/debit card fee income	3,562	3,287	10,420	8,691
Income from bank owned life insurance	1,093	1,047	3,260	4,423
Gain on sale of available for sale securities	280	582	1,569	609
Broker commissions	3,839	5,297	13,462	14,823
Other non-interest income	10,005	6,854	27,012	19,430
Total non-interest income	57,478	47,112	167,890	126,554
Non-interest Expense
Salaries and employee benefits	82,416	64,934	239,131	193,641
Net occupancy and equipment	17,987	14,883	51,613	44,977
Impairment of FDIC loss share receivables and other long-lived assets	1,896	4,741	1,884	5,378
Communication and delivery	3,420	2,525	10,164	8,756
Marketing and business development	3,260	2,624	11,003	8,886
Data processing	6,727	5,693	27,928	21,196
Professional services	5,825	4,267	18,657	13,575
Credit and other loan related expense	5,241	4,569	14,154	11,208
Insurance	4,614	3,846	12,402	10,518
Travel and entertainment	2,248	2,289	7,489	6,745
Other non-interest expense	11,334	9,741	36,905	29,599
Total non-interest expense	144,968	120,112	431,330	354,479
Income before income tax expense	62,565	43,037	143,961	94,942
Income tax expense	20,090	12,144	45,524	25,497
Net Income	42,475	30,893	98,437	69,445
Income Available to Common Shareholders - Basic	42,475	30,893	98,437	69,445
Earnings Allocated to Unvested Restricted Stock	(492)	(462)	(1,171)	(1,114)
Earnings Allocated to Common Shareholders	$ 41,983	$ 30,431	$ 97,266	$ 68,331
Earnings per common share - Basic (in usd per share)	$ 1.04	$ 0.93	$ 2.60	$ 2.22
Earnings per common share - Diluted (in usd per share)	1.03	0.92	2.59	2.21
Cash dividends declared per share (in usd per share)	$ 0.34	$ 0.34	$ 1.02	$ 1.02
Comprehensive Income
Net Income	$ 42,475	$ 30,893	$ 98,437	$ 69,445
Unrealized gains (losses) on securities:
Unrealized holding gains (losses) arising during the period (net of tax effects of $6,681, $2,461, $5,843 and $8,955, respectively)	12,408	(4,571)	10,852	16,631
Reclassification adjustment for gains included in net income (net of tax effects of $98, $204, $549 and $213, respectively)	(182)	(378)	(1,020)	(396)
Unrealized gains (losses) on securities, net of tax	12,226	(4,949)	9,832	16,235
Fair value of derivative instruments designated as cash flow hedges:
Change in fair value of derivative instruments designated as cash flow hedges during the period (net of tax effects of $1,837, $0, $201 and $0, respectively)	(3,412)	0	(374)	0
Reclassification adjustment for losses included in net income	0	0	0	0
Fair value of derivative instruments designated as cash flow hedges, net of tax	(3,412)	0	(374)	0
Other comprehensive income (loss), net of tax	8,814	(4,949)	9,458	16,235
Comprehensive Income	$ 51,289	$ 25,944	$ 107,895	$ 85,680

Consolidated Statements of Com5

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Unrealized holding gains arising during the period net of tax effects	$ 6,681	$ 2,461	$ 5,843	$ 8,955
Reclassification adjustment for gains included in net income net of tax effects	98	204	549	213
Change in fair value of derivative instruments designated as cash flow hedges net of tax effects	$ 1,837	$ 0	$ 201	$ 0

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands		Total	Preferred Stock	Common Stock		Additional Paid-In Capital		Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock at Cost
Beginning balance (in shares) at Dec. 31, 2013			0	31,917,385
Beginning balance at Dec. 31, 2013		$ 1,530,346	$ 0	$ 31,917		$ 1,178,284		$ 435,508	$ (16,491)	$ (98,872)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		69,445						69,445
Other comprehensive income		16,235							16,235
Cash dividends declared, $1.02 per share		(32,943)						(32,943)
Common stock issued under incentive plans, net of shares surrendered in payment, including tax benefit		8,999				2,168				6,831
Common stock issued for acquisitions (in shares)				3,345,516
Common stock issued for acquisitions		214,665		$ 3,346		211,319
Stock issued		0				(6,080)				6,080
Share-based compensation cost		8,927				8,927
Ending balance (in shares) at Sep. 30, 2014			0	35,262,901
Ending balance at Sep. 30, 2014		1,815,674	$ 0	$ 35,263		1,394,618		472,010	(256)	(85,961)
Beginning balance (in shares) at Dec. 31, 2014			0	35,262,901
Beginning balance at Dec. 31, 2014		1,852,148	$ 0	$ 35,263		1,398,633		496,573	7,525	(85,846)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		98,437						98,437
Other comprehensive income		9,458							9,458
Cash dividends declared, $1.02 per share		(40,945)						(40,945)
Reclassification of treasury stock under the LBCA (in shares)	[1]			(1,809,497)
Reclassification of treasury stock under the LBCA		0		$ (1,809)	[1]	(84,037)	[1]			85,846	[1]
Common stock issued under incentive plans, net of shares surrendered in payment, including tax benefit (in shares)				200,958
Common stock issued under incentive plans, net of shares surrendered in payment, including tax benefit		1,748		$ 201		1,547				0
Common stock issued for acquisitions (in shares)				7,474,404
Common stock issued for acquisitions		474,753		$ 7,474		467,279
Preferred stock issued, shares			8,000
Stock issued		77,463	$ 8			77,455
Share-based compensation cost		10,139				10,139
Ending balance (in shares) at Sep. 30, 2015			8,000	41,128,766
Ending balance at Sep. 30, 2015		$ 2,483,201	$ 8	$ 41,129		$ 1,871,016		$ 554,065	$ 16,983	$ 0
[1]	Effective January 1, 2015, companies incorporated in Louisiana became subject to the Louisiana Business Corporation Act (“LBCA”), which eliminates the concept of treasury stock and provides that shares reacquired by a company are to be treated as authorized but unissued. Refer to Note 1 for further discussion.

Consolidated Statements of Sha7

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per share	$ 0.34	$ 0.34	$ 1.02	$ 1.02

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash Flows from Operating Activities
Net Income	$ 98,437	$ 69,445
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, and accretion	11,839	12,241
Amortization of purchase accounting adjustments, net	(14,657)	7,129
Provision for loan losses	19,197	12,565
Share-based compensation cost	10,139	8,927
Gain on sale of assets, net	(2,384)	7
Gain on sale of available for sale securities	(1,569)	(609)
Gain on sale of OREO, net	(3,216)	(3,253)
Impairment of FDIC loss share receivables and other long-lived assets	1,884	5,378
Amortization of premium/discount on securities, net	13,217	10,248
Provision (benefit) for deferred income taxes	3,244	(24,328)
Originations of mortgage loans held for sale	(1,880,856)	(1,218,684)
Proceeds from sales of mortgage loans held for sale	1,887,468	1,234,694
Gain on sale of mortgage loans held for sale, net	(60,109)	(41,412)
Tax benefit associated with share-based payment arrangements	(408)	(1,163)
Change in other assets, net of other assets acquired	25,633	23,514
Other operating activities, net	15,493	(14,914)
Net Cash Provided by Operating Activities	123,352	79,785
Cash Flows from Investing Activities
Proceeds from sales of available for sale securities	212,278	20,531
Proceeds from maturities, prepayments and calls of available for sale securities	367,064	413,069
Purchases of available for sale securities	(934,638)	(540,197)
Proceeds from maturities, prepayments and calls of held to maturity securities	17,937	32,880
Reimbursement of recoverable covered asset losses from (to) the FDIC	1,429	(457)
Increase in loans, net	(491,545)	(476,329)
Proceeds from sale of premises and equipment	9,113	6,217
Purchases of premises and equipment, net of premises and equipment acquired	(14,144)	(26,587)
Proceeds from disposition of OREO	38,739	69,124
Cash paid for additional investment in tax credit entities	(7,868)	(10,384)
Cash received in excess of cash paid for acquisitions	425,581	188,803
Other investing activities, net	14,695	(16,073)
Net Cash Used in Investing Activities	(361,359)	(339,403)
Cash Flows from Financing Activities
Increase in deposits, net of deposits acquired	1,092,943	497,970
Net change in short-term borrowings, net of borrowings acquired	(624,811)	77,338
Proceeds from long-term debt	63,125	4,637
Repayments of long-term debt	(200,031)	(21,012)
Cash dividends paid on common stock	(38,334)	(31,701)
Proceeds from common stock transactions	4,825	11,141
Payments to repurchase common stock	(3,404)	(3,307)
Net proceeds from issuance of preferred stock	77,463	0
Tax benefit associated with share-based payment arrangements	408	1,163
Net Cash Provided by Financing Activities	372,184	536,229
Net Increase in Cash and Cash Equivalents	134,177	276,611
Cash and Cash Equivalents at Beginning of Period	548,095	391,396
Cash and Cash Equivalents at End of Period	682,272	668,007
Supplemental Schedule of Noncash Activities
Acquisition of real estate in settlement of loans	14,921	20,219
Common stock issued in acquisitions	474,753	214,665
Supplemental Disclosures Cash paid for:
Income taxes, net	42,899	30,984
Income taxes, net	$ 28,929	$ 42,933

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION General The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information or footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments, consisting of normal and recurring items, necessary for a fair presentation of the consolidated financial statements have been made. These interim financial statements should be read in conjunction with the audited consolidated financial statements and footnote disclosures for IBERIABANK Corporation (the “Company”) previously filed with the Securities and Exchange Commission (the “SEC”) in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. Operating results for the three and nine month periods ended September 30, 2015 are not necessarily indicative of the results that may be expected for the year ended December 31, 2015. The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, IBERIABANK, Lenders Title Company (“LTC”), IBERIA Capital Partners, LLC (“ICP”), 1887 Leasing, LLC, IBERIA Asset Management, Inc. (“IAM”), and IBERIA CDE, LLC (“CDE”). All significant intercompany balances and transactions have been eliminated in consolidation. The Company offers commercial and retail banking products and services to customers throughout locations in seven states through IBERIABANK. The Company also operates mortgage production offices in 10 states through IBERIABANK Mortgage Company (“IMC”), a subsidiary of IBERIABANK, and offers a full line of title insurance and closing services throughout Arkansas and Louisiana through LTC and its subsidiaries. ICP provides equity research, institutional sales and trading, and corporate finance services. 1887 Leasing, LLC owns an aircraft used by management of the Company. IAM provides wealth management and trust services for commercial and private banking clients. CDE is engaged in the purchase of tax credits. Reclassifications Certain amounts reported in prior periods have been reclassified to conform to the current period presentation. These reclassifications did not have a material effect on previously reported consolidated net income, shareholders’ equity or cash flows. Louisiana Business Corporation Act Effective January 1, 2015, companies incorporated under Louisiana law became subject to the Louisiana Business Corporation Act (which replaced the Louisiana Business Corporation Law). Provisions of the Louisiana Business Corporation Act eliminate the concept of treasury stock and provide that shares reacquired by a company are to be treated as authorized but unissued shares. As a result of this change in law, shares previously classified as treasury stock are presented as a reduction to issued shares of common stock in the consolidated financial statements as of September 30, 2015 , reducing the stated value of common stock and additional paid-in capital. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Material estimates that are susceptible to significant change in the near term are the allowance for credit losses, accounting for loans covered by loss sharing arrangements with the FDIC and the related loss share receivables, and determination of the fair value of net assets acquired in acquisitions. Concentrations of Credit Risk Most of the Company’s business activity is with customers located within the states of Louisiana, Florida, Arkansas, Alabama, Texas, Tennessee and Georgia. The Company’s lending activity is concentrated in its market areas in those states. The Company has emphasized originations of commercial loans and private banking loans, defined as loans to larger consumer clients. Repayments on loans are expected to come from cash flows of the borrower and/or guarantor. Losses on secured loans are limited by the value of the collateral upon default of the borrowers. The Company does not have any significant concentrations to any one industry or customer.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2015
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS ASU No. 2014-01 In January 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-01, “ Investments – Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects (a consensus of the FASB Emerging Issues Task Force)”. The ASU allows for use of the proportional amortization method for investments in qualified affordable housing projects if certain conditions are met. Under the proportional amortization method, the initial cost of the investment is amortized in proportion to the tax credits and other tax benefits received and the net investment performance is recognized in the consolidated statements of comprehensive income as a component of income tax expense. ASU 2014-01 provides for a practical expedient, which allows for amortization of the investment in proportion to only the tax credits if it produces a measurement that is substantially similar to the measurement that would result from using both tax credits and other tax benefits. ASU 2014-01 was effective for fiscal years and interim periods beginning after December 15, 2014. The Company adopted this guidance effective January 1, 2015, utilizing the practical expedient method. Amortization expense related to qualified affordable housing investments has been presented net of the income tax credits in income tax expense in the unaudited consolidated statements of comprehensive income. The standard was required to be applied retrospectively, therefore, prior periods have been restated in accordance with GAAP. The impact of the adoption of ASU 2014-01 was not material to the consolidated financial statements in current or prior periods. ASU No. 2015-02 In February 2015, the FASB issued ASU No. 2015-02, Consolidation: Amendments to the Consolidation Analysis , which changes the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The amendments in the guidance: 1) modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities (VIEs) or voting interest entities, 2) eliminate the presumption that a general partner should consolidate a limited partnership, 3) affect the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships, and 4) provide a scope exception from consolidation guidance for certain investment funds. ASU No. 2015-02 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The guidance may be applied using a modified retrospective approach by recording a cumulative effect adjustment to equity as of the beginning of the fiscal year of adoption. The amendments may also be applied retrospectively. The Company is still evaluating this ASU but does not expect that adoption will have a significant impact on the Company’s consolidated financial statements. ASU No. 2015-16 In September 2015, the FASB issued ASU No. 2015-16, Business Combinations: Simplifying the Accounting for Measurement-Period Adjustments. ASU No. 2015-16 requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined and present separately on the face of the income statement or disclose in the notes the portion of the amount recorded in current-period earnings by line item that would have been have been recorded in previous reporting periods if the adjustment had been recognized as of the acquisition date. ASU No. 2015-16 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The guidance must be applied prospectively to adjustments to provisional amounts that occur after the effective date of this update with earlier application permitted for financial statements that have not been issued. The Company adopted this guidance effective September 30, 2015. The adoption of this ASU did not have a significant impact on the Company’s consolidated financial statements.

Acquisition Activity

Acquisition Activity	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Acquisition Activity	ACQUISITION ACTIVITY Acquisition of Florida Bank Group, Inc. On February 28, 2015 , the Company acquired Florida Bank Group, Inc. (“Florida Bank Group”), the holding company of Florida Bank, a Tampa, Florida-based commercial bank servicing Tampa, Tallahassee and Jacksonville, Florida. Under the terms of the agreement, Florida Bank Group shareholders received a combination of cash and shares of the Company’s common stock. Florida Bank Group shareholders received cash equal to $7.81 per share of then outstanding Florida Bank Group common stock, including shares of preferred stock that converted to common shares in the acquisition. Each Florida Bank Group common share was exchanged for 0.149 share of the Company’s common stock, as well as a cash payment for any fractional share. All unexercised Florida Bank Group stock options at the closing date were settled for cash at fair value based on the closing price. The Company acquired all of the outstanding common stock of the former Florida Bank Group shareholders for total consideration of $90.5 million , which resulted in goodwill of $16.7 million , as shown in the table below. With this acquisition, IBERIABANK expanded its presence in the Tampa, Tallahassee and Jacksonville areas of Florida through the addition of 12 bank offices and an experienced in-market team that enhances IBERIABANK’s ability to compete in that market. The Company projects cost savings will be recognized in future periods through the elimination of redundant operations. The following summarizes consideration paid and a preliminary allocation of purchase price to net assets acquired. (Dollars in thousands) Number of Shares Amount Equity consideration Common stock issued 752,493 $ 47,497 Total equity consideration 47,497 Non-Equity consideration Cash 42,988 Total consideration paid 90,485 Fair value of net assets assumed including identifiable intangible assets 73,736 Goodwill $ 16,749 Acquisition of Old Florida Bancshares, Inc. On March 31, 2015 , the Company acquired Old Florida Bancshares, Inc. (“Old Florida”), the holding company of Old Florida Bank and New Traditions Bank, Orlando, which were Florida-based commercial banks. Under terms of the agreement, for each share of Old Florida common stock outstanding, Old Florida shareholders received 0.34 of a share of the Company’s common stock, as well as a cash payment for any fractional share. The Company acquired all of the outstanding common stock of the former Old Florida shareholders for total consideration of $253.2 million , which resulted in goodwill of $99.5 million , as shown in the table below. With this acquisition, IBERIABANK expanded its presence into the Orlando, Florida MSA through the addition of 14 bank offices and an experienced in-market team. The Company projects cost savings will be recognized in future periods through the elimination of redundant operations. The following summarizes consideration paid and a preliminary allocation of purchase price to net assets acquired. (Dollars in thousands) Number of Shares Amount Equity consideration Common stock issued 3,839,554 $ 242,007 Total equity consideration 242,007 Non-Equity consideration Cash 11,145 Total consideration paid 253,152 Fair value of net assets assumed including identifiable intangible assets 153,621 Goodwill $ 99,531 Acquisition of Georgia Commerce Bancshares, Inc. On May 31, 2015, the Company acquired Georgia Commerce Bancshares, Inc. (“Georgia Commerce”), holding company of Georgia Commerce Bank. Under the terms of the agreement, Georgia Commerce shareholders received 0.6134 of a share of the Company’s common stock for each of the Georgia Commerce common stock shares outstanding, as well as a cash payment for any fractional share. All unexercised Georgia Commerce stock options on the closing date were settled for cash at fair value based on the closing price. The Company acquired all of the outstanding common stock of the former Georgia Commerce shareholders for total consideration of $ 190.3 million , which resulted in goodwill of $ 81.2 million , as shown in the table below. With this acquisition, IBERIABANK expanded its presence into the Atlanta, Georgia MSA through the addition of nine bank offices and an experienced in-market team. The Company projects cost savings will be recognized in future periods through the elimination of redundant operations. The following summarizes consideration paid and a preliminary allocation of purchase price to net assets acquired. (Dollars in thousands) Number of Shares Amount Equity consideration Common stock issued 2,882,357 $ 185,249 Total equity consideration 185,249 Non-Equity consideration Cash 5,015 Total consideration paid 190,264 Fair value of net assets assumed including identifiable intangible assets 109,024 Goodwill $ 81,240 The Company accounted for the aforementioned business combinations under the acquisition method in accordance with ASC Topic 805, Business Combinations . Accordingly, the purchase price is allocated to the fair value of the assets acquired and liabilities assumed as of the date of acquisition. The following purchase price allocations on these acquisitions are preliminary and will be finalized upon the receipt of final valuations on certain assets and liabilities. In conjunction with the adoption of ASU 2015-16 as of September 30, 2015, upon receipt of final fair value estimates during the measurement period, which must be within one year of the acquisition dates, the Company will record any adjustments to the preliminary fair value estimates in the reporting period in which the adjustments are determined. Information regarding the Company’s loan discount and related deferred tax asset, core deposit intangible asset and related deferred tax liability, as well as income taxes payable and the related deferred tax balances, among other assets and liabilities recorded in the acquisitions may be adjusted as the Company refines its estimates. Determining the fair value of assets and liabilities, particularly illiquid assets and liabilities, is a complicated process involving significant judgment regarding estimates and assumptions used to calculate estimated fair value. Fair value adjustments based on updated estimates could materially affect the goodwill recorded on the acquisition. The Company may incur losses on the acquired loans that are materially different from losses the Company originally projected. The acquired assets and liabilities, as well as the preliminary adjustments to record the assets and liabilities at their estimated fair values, are presented in the following tables. Florida Bank Group (Dollars in thousands) As Acquired Preliminary Fair Value Adjustments As recorded by the Company Assets Cash and cash equivalents $ 72,982 $ — $ 72,982 Investment securities 107,236 136 (1) 107,372 Loans 312,902 (7,073 ) (2) 305,829 Other real estate owned 498 (75 ) (3) 423 Core deposit intangible — 4,489 (4) 4,489 Deferred tax asset, net 19,889 9,232 (5) 29,121 Other assets 29,810 (8,949 ) (6) 20,861 Total Assets $ 543,317 $ (2,240 ) $ 541,077 Liabilities Interest-bearing deposits $ 282,417 $ 263 (7) $ 282,680 Non-interest-bearing deposits 109,548 — 109,548 Borrowings 60,000 8,598 (8) 68,598 Other liabilities 1,897 4,618 (9) 6,515 Total Liabilities $ 453,862 $ 13,479 $ 467,341 Explanation of certain fair value adjustments: (1) The amount represents the adjustment of the book value of Florida Bank Group’s investments to their estimated fair value on the date of acquisition. (2) The amount represents the adjustment of the book value of Florida Bank Group's loans to their estimated fair value based on current interest rates and expected cash flows, which includes estimates of expected credit losses inherent in the portfolio. (3) The adjustment represents the adjustment of Florida Bank Group's OREO to its estimated fair value on the date of acquisition. (4) The amount represents the fair value of the core deposit intangible asset created in the acquisition. (5) The amount represents the deferred tax asset recognized on the fair value adjustment of Florida Bank Group acquired assets and assumed liabilities. (6) The amount represents the adjustment of the book value of Florida Bank Group’s property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value. (7) The adjustment is necessary because the weighted average interest rate of Florida Bank Group’s deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio, which is estimated at 51 months . (8) The amount represents the adjustment of the book value of Florida Bank Group’s borrowings to their estimated fair value based on current interest rates and the credit characteristics inherent in the liability. (9) The amount is necessary to record Florida Bank Group's rent liability at fair value. Old Florida (Dollars in thousands) As Acquired Preliminary Fair Value Adjustments As recorded by the Company Assets Cash and cash equivalents $ 360,688 $ — $ 360,688 Investment securities 67,209 — 67,209 Loans held for sale 5,952 — 5,952 Loans 1,073,773 (9,342 ) (1) 1,064,431 Other real estate owned 4,515 (2 ) (2) 4,513 Core deposit intangible — 10,055 (3) 10,055 Deferred tax asset, net 8,470 3,181 (4) 11,651 Other assets 30,732 (7,238 ) (5) 23,494 Total Assets $ 1,551,339 $ (3,346 ) $ 1,547,993 Liabilities Interest-bearing deposits $ 1,048,765 $ 123 (6) $ 1,048,888 Non-interest-bearing deposits 340,869 — 340,869 Borrowings 1,528 — 1,528 Other liabilities 3,011 76 (7) 3,087 Total Liabilities $ 1,394,173 $ 199 $ 1,394,372 Explanation of certain fair value adjustments: (1) The amount represents the adjustment of the book value of Old Florida's loans to their estimated fair value based on current interest rates and expected cash flows, which includes estimates of expected credit losses inherent in the portfolio. (2) The adjustment represents the adjustment of Old Florida's OREO to its estimated fair value on the date of acquisition. (3) The amount represents the fair value of the core deposit intangible asset created in the acquisition. (4) The amount represents the net deferred tax asset recognized on the fair value adjustment of Old Florida acquired assets and assumed liabilities. (5) The amount represents the adjustment of the book value of Old Florida’s property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value. (6) The adjustment is necessary because the weighted average interest rate of Old Florida’s deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio, which is estimated at 56 months . (7) The adjustment is necessary to record Old Florida's rent liability at fair value. Georgia Commerce (Dollars in thousands) As Acquired Preliminary As recorded by Assets Cash and cash equivalents $ 51,059 $ — $ 51,059 Investment securities 139,035 (806 ) (1) 138,229 Loans held for sale 1,249 — 1,249 Loans 807,726 (6,622 ) (2) 801,104 Other real estate owned 9,795 (4,182 ) (3) 5,613 Core deposit intangible — 7,448 (4) 7,448 Deferred tax asset, net 5,030 1,849 (5) 6,879 Other assets 30,587 (657 ) (6) 29,930 Total Assets $ 1,044,481 $ (2,970 ) $ 1,041,511 Liabilities Interest-bearing deposits 658,133 176 (7) 658,309 Non-interest-bearing deposits 249,739 — 249,739 Borrowings 13,203 — 13,203 Other liabilities 11,236 — 11,236 Total Liabilities $ 932,311 $ 176 $ 932,487 Explanation of certain fair value adjustments: (1) The amount represents the adjustment of the book value of Georgia Commerce’s investments to their estimated fair value on the date of acquisition. (2) The amount represents the adjustment of the book value of Georgia Commerce's loans to their estimated fair value based on current interest rates and expected cash flows, which includes estimates of expected credit losses inherent in the portfolio. (3) The adjustment represents the adjustment of Georgia Commerce's OREO to its estimated fair value on the date of acquisition. (4) The amount represents the fair value of the core deposit intangible asset created in the acquisition. (5) The amount represents the net deferred tax asset recognized on the fair value adjustment of Georgia Commerce acquired assets and assumed liabilities. (6) The amount represents the adjustment of the book value of Georgia Commerce’s property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value. (7) The adjustment is necessary because the weighted average interest rate of Georgia Commerce’s deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio, which is estimated at 60 months . Supplemental unaudited pro forma information The following unaudited pro forma information for the nine months ended September 30, 2014 reflects the Company’s estimated consolidated results of operations as if the acquisitions of Florida Bank Group, Old Florida, and Georgia Commerce occurred at January 1, 2014, unadjusted for potential cost savings and/or synergies and preliminary purchase price adjustments. For the Nine Months Ended (Dollars in thousands, except per share data) September 30, 2014 Interest and non-interest income $ 586,979 Net income 88,615 Earnings per share - basic 2.28 Earnings per share - diluted 2.28 The Company’s consolidated financial statements as of and for the nine months ended September 30, 2015 include the operating results of the acquired assets and assumed liabilities for the days subsequent to the respective acquisition dates. Due to the system conversion of the acquired entities throughout the current nine-month period and subsequent integration of the operating activities of the acquired branches into existing Company markets, historical reporting for the former Florida Bank Group, Old Florida and Georgia Commerce branches is impracticable and thus disclosure of the revenue from the assets acquired and income before income taxes is impracticable for the period subsequent to acquisition.

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Investment Securities	INVESTMENT SECURITIES The amortized cost and fair values of investment securities, with gross unrealized gains and losses, consist of the following: September 30, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 277,822 $ 2,743 $ (45 ) $ 280,520 Obligations of states and political subdivisions 181,626 4,502 — 186,128 Mortgage-backed securities 2,246,002 22,157 (3,647 ) 2,264,512 Other securities 96,301 694 (350 ) 96,645 Total securities available for sale $ 2,801,751 $ 30,096 $ (4,042 ) $ 2,827,805 Securities held to maturity: Obligations of states and political subdivisions $ 73,821 $ 2,878 $ (74 ) $ 76,625 Mortgage-backed securities 24,509 103 (626 ) 23,986 Total securities held to maturity $ 98,330 $ 2,981 $ (700 ) $ 100,611 December 31, 2014 Amortized Cost Gross Gross Estimated (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 317,386 $ 1,700 $ (3,533 ) $ 315,553 Obligations of states and political subdivisions 86,513 3,679 (2 ) 90,190 Mortgage-backed securities 1,741,917 16,882 (7,184 ) 1,751,615 Other securities 1,460 35 — 1,495 Total securities available for sale $ 2,147,276 $ 22,296 $ (10,719 ) $ 2,158,853 Securities held to maturity: U.S. Government-sponsored enterprise obligations $ 10,000 $ 88 $ — $ 10,088 Obligations of states and political subdivisions 77,597 3,153 (145 ) 80,605 Mortgage-backed securities 29,363 151 (726 ) 28,788 Total securities held to maturity $ 116,960 $ 3,392 $ (871 ) $ 119,481 Securities with carrying values of $1.3 billion and $1.4 billion were pledged to secure public deposits and other borrowings at September 30, 2015 and December 31, 2014 , respectively. Information pertaining to securities with gross unrealized losses, aggregated by investment category and length of time that individual securities have been in a continuous loss position, is as follows: September 30, 2015 Less Than Twelve Months Over Twelve Months Total Gross Unrealized Losses Estimated Fair Value Gross Estimated Gross Estimated (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ — $ — $ (45 ) $ 28,449 $ (45 ) $ 28,449 Mortgage-backed securities (954 ) 252,358 (2,693 ) 191,836 (3,647 ) 444,194 Other securities (346 ) 27,626 (4 ) 505 (350 ) 28,131 Total securities available for sale $ (1,300 ) $ 279,984 $ (2,742 ) $ 220,790 $ (4,042 ) $ 500,774 Securities held to maturity: Obligations of states and political subdivisions $ (6 ) $ 3,642 $ (68 ) $ 4,199 $ (74 ) $ 7,841 Mortgage-backed securities (17 ) 1,054 (609 ) 18,286 (626 ) 19,340 Total securities held to maturity $ (23 ) $ 4,696 $ (677 ) $ 22,485 $ (700 ) $ 27,181 December 31, 2014 Less Than Twelve Months Over Twelve Months Total Gross Estimated Gross Estimated Gross Estimated (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ — $ — $ (3,533 ) $ 240,498 $ (3,533 ) $ 240,498 Obligations of states and political subdivisions (2 ) 185 — — (2 ) 185 Mortgage-backed securities (1,189 ) 304,686 (5,995 ) 294,549 (7,184 ) 599,235 Total securities available for sale $ (1,191 ) $ 304,871 $ (9,528 ) $ 535,047 $ (10,719 ) $ 839,918 Securities held to maturity: Obligations of states and political subdivisions $ (9 ) $ 2,287 $ (136 ) $ 8,590 $ (145 ) $ 10,877 Mortgage-backed securities — — (726 ) 20,812 (726 ) 20,812 Total securities held to maturity $ (9 ) $ 2,287 $ (862 ) $ 29,402 $ (871 ) $ 31,689 The Company assessed the nature of the losses in its portfolio as of September 30, 2015 and December 31, 2014 to determine if there are losses that should be deemed other-than-temporary. In its analysis of these securities, management considered numerous factors to determine whether there were instances where the amortized cost basis of the debt securities would not be fully recoverable, including, but not limited to: • The length of time and extent to which the estimated fair value of the securities was less than their amortized cost, • Whether adverse conditions were present in the operations, geographic area, or industry of the issuer, • The payment structure of the security, including scheduled interest and principal payments, the issuer’s failure to make scheduled payments, if any, and the likelihood of failure to make scheduled payments in the future, • Changes to the rating of the security by a rating agency, and • Subsequent recoveries or additional declines in fair value after the balance sheet date. Management believes it has considered these factors, as well as all relevant information available, when determining the expected future cash flows of the securities in question. In each instance, management has determined the cost basis of the securities would be fully recoverable. Management also has the intent to hold debt securities until their maturity or anticipated recovery if the security is classified as available for sale. In addition, management does not believe the Company will be required to sell debt securities before the anticipated recovery of the amortized cost basis of the security. As a result of the Company’s analysis, no declines in the estimated fair value of the Company’s investment securities were deemed to be other-than-temporary at September 30, 2015 or December 31, 2014 . At September 30, 2015 , 103 debt securities had unrealized losses of 0.89% of the securities’ amortized cost basis. At December 31, 2014 , 112 debt securities had unrealized losses of 1.31% of the securities’ amortized cost basis. The unrealized losses for each of the securities related to market interest rate changes and not credit concerns of the issuers. Additional information on securities that have been in a continuous loss position for over twelve months at September 30, 2015 and December 31, 2014 is presented in the following table. (Dollars in thousands) September 30, 2015 December 31, 2014 Number of securities Issued by Fannie Mae, Freddie Mac, or Ginnie Mae 39 66 Issued by political subdivisions 2 5 Other 1 — 42 71 Amortized cost basis Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 241,918 $ 566,113 Issued by political subdivisions 4,267 8,727 Other 509 — $ 246,694 $ 574,840 Unrealized loss Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 3,347 $ 10,254 Issued by political subdivisions 68 136 Other 4 — $ 3,419 $ 10,390 The Fannie Mae, Freddie Mac, and Ginnie Mae securities are rated AA+ by S&P and Aaa by Moody’s. Two of the securities in a continuous loss position for over twelve months were issued by political subdivisions. The securities issued by political subdivisions have credit ratings by S&P ranging from AA to AAA and credit ratings from Moody’s ranging from Aa2 to Aaa. The amortized cost and estimated fair value of investment securities by maturity at September 30, 2015 are shown in the following table. Securities are classified according to their contractual maturities without consideration of principal amortization, potential prepayments or call options. Accordingly, actual maturities may differ from contractual maturities. Weighted average yields are calculated on the basis of the yield to maturity based on the amortized cost of each security. Securities Available for Sale Securities Held to Maturity Weighted Average Yield Amortized Cost Estimated Fair Value Weighted Amortized Cost Estimated (Dollars in thousands) Within one year or less 1.63 % $ 25,724 $ 25,824 3.85 % $ 75 $ 75 One through five years 1.69 % 298,322 301,724 2.79 % 11,552 11,808 After five through ten years 2.23 % 516,467 524,969 3.09 % 20,663 21,494 Over ten years 2.12 % 1,961,238 1,975,288 2.98 % 66,040 67,234 2.09 % $ 2,801,751 $ 2,827,805 2.98 % $ 98,330 $ 100,611 The following is a summary of realized gains and losses from the sale of securities classified as available for sale. Gains or losses on securities sold are recorded on the trade date, using the specific identification method. Three Months Ended September 30, Nine Months Ended September 30, (Dollars in thousands) 2015 2014 2015 2014 Realized gains $ 425 $ 582 $ 1,786 $ 609 Realized losses (145 ) — (217 ) — $ 280 $ 582 $ 1,569 $ 609 In addition to the gains above, the Company realized certain immaterial gains on calls of held to maturity securities. Other Equity Securities The Company included the following securities, accounted for at amortized cost, which approximates fair value, in “Other assets” on the consolidated balance sheets: (Dollars in thousands) September 30, 2015 December 31, 2014 Federal Home Loan Bank (FHLB) stock $ 14,603 $ 38,476 Federal Reserve Bank (FRB) stock 48,584 34,348 Other investments 1,158 1,306 $ 64,345 $ 74,130

Loans

Loans	9 Months Ended
	Sep. 30, 2015
Receivables [Abstract]
Loans	LOANS Loans consist of the following, segregated into non-covered and covered loans, for the periods indicated: September 30, 2015 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans Total Commercial loans: Real estate $ 4,321,723 $ 1,614,438 $ 43,590 $ 5,979,751 Commercial and industrial 2,779,503 512,049 11,419 3,302,971 Energy-related 713,935 5,521 — 719,456 7,815,161 2,132,008 55,009 10,002,178 Residential mortgage loans: Residential 1-4 family 596,428 398,398 119,926 1,114,752 Construction / Owner Occupied 64,115 11,074 — 75,189 660,543 409,472 119,926 1,189,941 Consumer and other loans: Home equity 1,488,796 449,665 77,226 2,015,687 Indirect automobile 281,522 127 — 281,649 Other 533,236 92,948 1,380 627,564 2,303,554 542,740 78,606 2,924,900 Total $ 10,779,258 $ 3,084,220 $ 253,541 $ 14,117,019 December 31, 2014 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans (1) Total Commercial loans: Real estate $ 3,676,811 $ 495,842 $ 189,126 $ 4,361,779 Commercial and industrial 2,452,521 87,914 31,260 2,571,695 Energy-related 872,866 7,742 — 880,608 7,002,198 591,498 220,386 7,814,082 Residential mortgage loans: Residential 1-4 family 495,638 424,579 128,024 1,048,241 Construction / Owner Occupied 32,056 — — 32,056 527,694 424,579 128,024 1,080,297 Consumer and other loans: Home equity 1,290,976 217,699 92,430 1,601,105 Indirect automobile 396,766 392 — 397,158 Other 451,080 93,618 3,704 548,402 2,138,822 311,709 96,134 2,546,665 Total $ 9,668,714 $ 1,327,786 $ 444,544 $ 11,441,044 (1) Included as covered loans at December 31, 2014 is $174.7 million of assets whose reimbursable loss periods ended as of January 1, 2015. Since 2009, the Company has acquired certain assets and liabilities of six failed banks. Substantially all of the loans and foreclosed real estate that were acquired through these transactions are covered by loss share agreements between the FDIC and IBERIABANK, which afford IBERIABANK loss protection. Refer to Note 7 for additional information regarding the Company’s loss sharing agreements. Because of the loss protection provided by the FDIC, the risks of the loans and foreclosed real estate from these acquisitions are significantly different from those assets not covered under the loss share agreements. Accordingly, the Company presents loans subject to the loss share agreements as “covered loans” and loans that are not subject to the loss share agreements as “non-covered loans.” Deferred loan origination fees were $26.3 million and $20.6 million and deferred loan expenses were $10.7 million and $9.4 million at September 30, 2015 and December 31, 2014 , respectively. In addition to loans issued in the normal course of business, the Company considers overdrafts on customer deposit accounts to be loans and reclassifies these overdrafts as loans in its consolidated balance sheets. At September 30, 2015 and December 31, 2014 , overdrafts of $5.2 million and $5.6 million , respectively, have been reclassified to loans. Loans with carrying values of $4.0 billion and $ 3.1 billion were pledged as collateral for borrowings at September 30, 2015 and December 31, 2014 , respectively. Non-covered Loans The following tables provide an analysis of the aging of non-covered loans as of September 30, 2015 and December 31, 2014 . Due to the difference in accounting for acquired loans, the tables below further segregate the Company’s non-covered loans between loans originated by the Company (“legacy loans”) and acquired loans. September 30, 2015 Legacy loans Total Legacy Loans, Net of Unearned Income Recorded Investment > 90 days and Accruing Past Due (1) (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ — $ — $ 180 $ 180 $ 559,028 $ 559,208 $ — Commercial real estate - Other 1,225 1,763 14,541 17,529 3,744,986 3,762,515 242 Commercial and industrial 1,087 672 11,139 12,898 2,766,605 2,779,503 363 Energy-related — — 3,478 3,478 710,457 713,935 — Residential mortgage 1,832 2,054 15,730 19,616 640,927 660,543 851 Consumer - Home equity 2,232 853 5,343 8,428 1,480,368 1,488,796 65 Consumer - Indirect automobile 1,927 470 1,129 3,526 277,996 281,522 — Consumer - Credit card 247 116 335 698 76,018 76,716 — Consumer - Other 900 339 920 2,159 454,361 456,520 — Total $ 9,450 $ 6,267 $ 52,795 $ 68,512 $ 10,710,746 $ 10,779,258 $ 1,521 December 31, 2014 Legacy loans Total Legacy Recorded Investment > 90 days and Accruing Past Due (1) (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ 507 $ — $ 69 $ 576 $ 483,663 $ 484,239 $ — Commercial real estate - Other 11,799 148 6,859 18,806 3,173,766 3,192,572 — Commercial and industrial 1,589 1,860 3,225 6,674 2,445,847 2,452,521 200 Energy-related — — 27 27 872,839 872,866 — Residential mortgage 1,389 2,616 14,900 18,905 508,789 527,694 538 Consumer - Home equity 4,096 595 7,420 12,111 1,278,865 1,290,976 16 Consumer - Indirect automobile 2,447 396 1,419 4,262 392,504 396,766 — Consumer - Credit card 253 163 1,032 1,448 71,297 72,745 — Consumer - Other 1,285 424 773 2,482 375,853 378,335 — Total $ 23,365 $ 6,202 $ 35,724 $ 65,291 $ 9,603,423 $ 9,668,714 $ 754 (1) Past due loans greater than 90 days days include all loans on non-accrual status, regardless of past due status, as of the period indicated. Non-accrual loans are presented separately in the “Non-accrual Loans” section below. September 30, 2015 Non-covered acquired loans Past Due (1) Discount/Premium Total Non-covered Acquired Loans, Net of Unearned Income Recorded Investment > 90 days and Accruing (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ — $ 260 $ 6,965 $ 7,225 $ 118,084 $ (1,548 ) $ 123,761 $ 6,965 Commercial real estate - Other 3,267 25 40,206 43,498 1,487,123 (39,944 ) 1,490,677 39,066 Commercial and industrial 1,464 346 6,566 8,376 508,047 (4,374 ) 512,049 5,882 Energy-related 95 382 1,392 1,869 3,652 — 5,521 1,392 Residential mortgage 85 846 5,470 6,401 407,673 (4,602 ) 409,472 4,430 Consumer - Home equity 1,063 221 6,097 7,381 452,928 (10,644 ) 449,665 5,643 Consumer - Indirect automobile — 5 19 24 142 (39 ) 127 19 Consumer - Other 593 116 646 1,355 95,353 (3,760 ) 92,948 575 Total $ 6,567 $ 2,201 $ 67,361 $ 76,129 $ 3,073,002 $ (64,911 ) $ 3,084,220 $ 63,972 December 31, 2014 Non-covered acquired loans Past Due (1) Discount/Premium Total Non-covered Acquired Loans, Net of Unearned Income Recorded Investment > 90 days and Accruing (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ 2,740 $ 57 $ 1,284 $ 4,081 $ 26,667 $ (1,170 ) $ 29,578 $ 1,284 Commercial real estate - Other 4,419 840 26,480 31,739 473,644 (39,119 ) 466,264 26,376 Commercial and industrial 2,106 70 1,624 3,800 89,338 (5,224 ) 87,914 1,635 Energy-related — — 11 11 7,731 — 7,742 — Residential mortgage 152 2,367 9,339 11,858 418,552 (5,831 ) 424,579 8,087 Consumer - Home equity 649 385 8,774 9,808 216,310 (8,419 ) 217,699 8,383 Consumer - Indirect automobile 13 17 9 39 393 (40 ) 392 9 Consumer - Other 1,458 113 1,949 3,520 94,315 (4,217 ) 93,618 1,829 Total $ 11,537 $ 3,849 $ 49,470 $ 64,856 $ 1,326,950 $ (64,020 ) $ 1,327,786 $ 47,603 (1) Past due information presents acquired loans at the gross loan balance, prior to application of discounts. Non-accrual Loans The following table provides the recorded investment of legacy loans on non-accrual status at the periods indicated. (Dollars in thousands) September 30, 2015 December 31, 2014 Commercial real estate - Construction $ 180 $ 69 Commercial real estate - Other 14,299 6,859 Commercial and industrial 10,776 3,025 Energy-related 3,478 27 Residential mortgage 14,879 14,362 Consumer - Home equity 5,278 7,404 Consumer - Indirect automobile 1,129 1,419 Consumer - Credit card 335 1,032 Consumer - Other 920 773 Total $ 51,274 $ 34,970 Covered Loans The carrying amount of the acquired covered loans at September 30, 2015 and December 31, 2014 consisted of loans determined to be impaired at the acquisition date, which are accounted for in accordance with ASC Topic 310-30, Receivables – Loans and Debt Securities Acquired with Deteriorated Credit Quality , and loans that were considered to be performing at the acquisition date, accounted for by analogy to ASC Topic 310-30, as detailed in the following tables. September 30, 2015 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Loans Total Covered Loans Commercial loans: Real estate $ 18,576 $ 25,014 $ 43,590 Commercial and industrial 567 10,852 11,419 19,143 35,866 55,009 Residential mortgage loans: Residential 1-4 family 25,100 94,826 119,926 25,100 94,826 119,926 Consumer and other loans: Home equity 8,038 69,188 77,226 Other 20 1,360 1,380 8,058 70,548 78,606 Total $ 52,301 $ 201,240 $ 253,541 December 31, 2014 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Loans Total Covered Loans Commercial loans: Real estate $ 1,253 $ 187,873 $ 189,126 Commercial and industrial — 31,260 31,260 1,253 219,133 220,386 Residential mortgage loans: Residential 1-4 family 22,918 105,106 128,024 22,918 105,106 128,024 Consumer and other loans: Home equity 12,872 79,558 92,430 Other 489 3,215 3,704 13,361 82,773 96,134 Total $ 37,532 $ 407,012 $ 444,544 Loans Acquired As discussed in Note 3, during the first nine months of 2015 , the Company acquired loans with fair values of $0.3 billion from Florida Bank Group, $1.1 billion from Old Florida and $0.8 billion from Georgia Commerce. Of the total $2.2 billion of loans acquired, $2.1 billion were determined to have no evidence of deteriorated credit quality and are accounted for under ASC Topics 310-10 and 310-20. The remaining $41.1 million were determined to exhibit deteriorated credit quality since origination under ASC 310-30. The tables below show the balances acquired during the first nine months of 2015 for these two subsections of the portfolio as of the acquisition date. These amounts are subject to change due to the finalization of purchase accounting adjustments. (Dollars in thousands) Contractually required principal and interest at acquisition $ 2,402,890 Expected losses and foregone interest (18,979 ) Cash flows expected to be collected at acquisition 2,383,911 Fair value of acquired loans at acquisition $ 2,130,276 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Impaired Loans Total Acquired Loans Contractually required principal and interest at acquisition $ 53,532 $ — $ 53,532 Non-accretable difference (expected losses and foregone interest) (7,852 ) — (7,852 ) Cash flows expected to be collected at acquisition 45,680 — 45,680 Accretable yield (4,592 ) — (4,592 ) Basis in acquired loans at acquisition $ 41,088 $ — $ 41,088 The following is a summary of changes in the accretable difference for loans accounted for under ASC 310-30 during the nine months ended September 30: 2015 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Impaired Loans Total Acquired Loans Balance at beginning of period $ 74,249 $ 213,402 $ 287,651 Acquisition 4,592 — 4,592 Transfers from non-accretable difference to accretable yield 70 7,129 7,199 Accretion (9,774 ) (50,531 ) (60,305 ) Changes in expected cash flows not affecting non-accretable differences (1) 1,209 (2,720 ) (1,511 ) Balance at end of period $ 70,346 $ 167,280 $ 237,626 2014 Acquired Impaired Loans Acquired Performing Impaired Loans Total Acquired Loans Balance at beginning of period $ 78,349 $ 276,543 $ 354,892 Acquisition 8,242 1,536 9,778 Transfers from non-accretable difference to accretable yield 3,952 13,872 17,824 Accretion (12,766 ) (66,590 ) (79,356 ) Changes in expected cash flows not affecting non-accretable differences (1) (6,873 ) (19,377 ) (26,250 ) Balance at end of period $ 70,904 $ 205,984 $ 276,888 (1) Includes changes in cash flows expected to be collected due to the impact of changes in actual or expected timing of liquidation events, modifications, changes in interest rates and changes in prepayment assumptions. Troubled Debt Restructurings Information about the Company’s troubled debt restructurings (“TDRs”) at September 30, 2015 and 2014 is presented in the following tables. Modifications of loans that are accounted for within a pool under ASC Topic 310-30, which include the covered loans above, as well as certain acquired loans are excluded as TDRs. Accordingly, such modifications do not result in the removal of those loans from the pool, even if the modification of those loans would otherwise be considered a TDR. As a result, all covered and certain acquired loans that would otherwise meet the criteria for classification as a TDR are excluded from the tables below. TDRs totaling $48.6 million occurred during the nine -month period ended September 30, 2015 through modification of the original loan terms. No material TDRs occurred during the nine months ended September 30, 2014 . The following table provides information on how the TDRs were modified during the nine months ended September 30, 2015 : (Dollars in thousands) 2015 Extended maturities $ 15,932 Maturity and interest rate adjustment 23,552 Forbearance 1,228 Other concession(s) (1) 7,887 Total $ 48,599 (1) Other concessions include concessions or a combination of concessions that do not consist of maturity extensions, interest rate adjustments, forbearance or covenant modifications. Of the $48.6 million of TDRs occurring during the nine months ended September 30, 2015 , $3.4 million is energy-related and $21.8 million is on accrual status. The Company had no material residential mortgage or consumer TDRs occur during the nine months ended September 30, 2015 and 2014 . The following table presents the end of period balance for loans modified in a TDR during the nine-month period ended September 30, 2015 and the financial impact of those modifications. September 30, 2015 (In thousands, except number of loans) Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment (1) Commercial real estate 8 $ 26,408 $ 25,572 Commercial and industrial 18 19,798 19,643 Energy-related 1 3,434 3,384 Total 27 $ 49,640 $ 48,599 (1) Recorded investment includes any allowance for credit losses recorded on the TDRs at the dates indicated. Information detailing TDRs which defaulted during the nine months ended September 30, 2015 and 2014 , and which were modified in the previous twelve months (i.e., the twelve months prior to the default) is presented in the following table. The Company has defined a default as any loan with a loan payment that is currently past due greater than 30 days , or was past due greater than 30 days at any point during the previous twelve months, or since the date of modification, whichever is shorter. September 30, 2015 September 30, 2014 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate 4 $ 12,939 31 $ 58 Commercial and industrial 15 13,145 11 1,767 Energy-related 1 3,384 — — Consumer - Home Equity — — — — Consumer - Other — — 1 — Total 20 $ 29,468 43 $ 1,825

Allowance for Credit Losses and

Allowance for Credit Losses and Credit Quality	9 Months Ended
	Sep. 30, 2015
Receivables [Abstract]
Allowance for Credit Losses and Credit Quality	ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY Allowance for Credit Losses Activity A summary of changes in the allowance for credit losses for the covered loan and non-covered loan portfolios for the nine months ended September 30, is as follows: 2015 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans Total Allowance for loans losses at beginning of period $ 76,174 $ 9,193 $ 44,764 $ 130,131 Provision for loan losses before benefit attributable to FDIC loss share agreements 17,743 143 (31 ) 17,855 Adjustment attributable to FDIC loss share arrangements — — 1,342 1,342 Net provision for loan losses 17,743 143 1,311 19,197 Adjustment attributable to FDIC loss share arrangements — — (1,342 ) (1,342 ) Transfer of balance to OREO — (209 ) (357 ) (566 ) Transfer of balance to non-covered — 28,700 (28,700 ) — Loans charged-off (12,073 ) (8,973 ) (1,188 ) (22,234 ) Recoveries 4,556 504 8 5,068 Allowance for loans losses at end of period 86,400 29,358 14,496 130,254 Reserve for unfunded commitments at beginning of period 11,801 — — 11,801 Provision for unfunded lending commitments 2,724 — — 2,724 Reserve for unfunded commitments at end of period 14,525 — — 14,525 Allowance for credit losses at end of period $ 100,925 $ 29,358 $ 14,496 $ 144,779 2014 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans Total Allowance for loans losses at beginning of period $ 67,342 $ 4,557 $ 71,175 $ 143,074 Provision for (Reversal of) loan losses before benefit attributable to FDIC loss share agreements 9,635 (1,795 ) 5,878 13,718 Adjustment attributable to FDIC loss share arrangements — — (1,153 ) (1,153 ) Net provision for (reversal of) loan losses 9,635 (1,795 ) 4,725 12,565 Adjustment attributable to FDIC loss share arrangements — — 1,153 1,153 Transfer of balance to OREO — (207 ) (5,171 ) (5,378 ) Loans charged-off (8,242 ) (586 ) (12,823 ) (21,651 ) Recoveries 4,338 401 38 4,777 Allowance for loans losses at end of period 73,073 2,370 59,097 134,540 Reserve for unfunded commitments at beginning of period 11,147 — — 11,147 Provision for unfunded lending commitments 952 — — 952 Reserve for unfunded commitments at end of period 12,099 — — 12,099 Allowance for credit losses at end of period $ 85,172 $ 2,370 $ 59,097 $ 146,639 A summary of changes in the allowance for credit losses for non-covered loans, by loan portfolio type, for the nine months ended September 30, is as follows: 2015 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 32,630 $ 26,486 $ 5,999 $ 2,875 $ 17,377 $ 85,367 (Reversal of) Provision for loan losses (356 ) 1,327 9,339 1,897 5,679 17,886 Transfer of balance to OREO 174 (169 ) — (143 ) (71 ) (209 ) Transfer of balance to non-covered 20,763 1,445 — — 6,492 28,700 Loans charged off (7,091 ) (1,162 ) (3 ) (283 ) (12,507 ) (21,046 ) Recoveries 1,543 164 — 48 3,305 5,060 Allowance for loans losses at end of period 47,663 28,091 15,335 4,394 20,275 115,758 Reserve for unfunded commitments Balance at beginning of period 3,370 3,733 1,596 168 2,934 11,801 (Reversal of) Provision for unfunded commitments 218 (149 ) 2,037 650 (32 ) 2,724 Balance at end of period 3,588 3,584 3,633 818 2,902 14,525 Allowance for credit losses at end of period $ 51,251 $ 31,675 $ 18,968 $ 5,212 $ 23,177 $ 130,283 Allowance on loans individually evaluated for impairment $ 883 $ 817 $ — $ — $ 16 $ 1,716 Allowance on loans collectively evaluated for impairment 50,368 30,858 18,968 5,212 23,161 128,567 Loans, net of unearned income: Balance at end of period $ 5,936,161 $ 3,291,552 $ 719,456 $ 1,070,015 $ 2,846,294 $ 13,863,478 Balance at end of period individually evaluated for impairment 27,299 25,231 — — 214 52,744 Balance at end of period collectively evaluated for impairment 5,874,262 3,255,580 719,456 1,056,797 2,838,500 13,744,595 Balance at end of period acquired with deteriorated credit quality 34,600 10,741 — 13,218 7,580 66,139 2014 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 26,126 $ 22,101 $ 6,878 $ 2,546 $ 14,248 $ 71,899 Provision for (Reversal of) loan losses 630 3,283 (1,115 ) 514 4,528 7,840 Transfer of balance to OREO — (130 ) — (12 ) (65 ) (207 ) Loans charged off (1,214 ) (1,097 ) — (607 ) (5,910 ) (8,828 ) Recoveries 2,209 93 — 134 2,303 4,739 Allowance for loans losses at end of period 27,751 24,250 5,763 2,575 15,104 75,443 Reserve for unfunded commitments at beginning of period 3,071 1,814 3,043 72 3,147 11,147 Provision for unfunded commitments 671 1,674 (1,427 ) 11 23 952 Reserve for unfunded commitments at end of period 3,742 3,488 1,616 83 3,170 12,099 Allowance for credit losses at end of period $ 31,493 $ 27,738 $ 7,379 $ 2,658 $ 18,274 $ 87,542 Allowance on loans individually evaluated for impairment $ 25 $ — $ — $ — $ — $ 25 Allowance on loans collectively evaluated for impairment 31,468 27,738 7,379 2,658 18,274 87,517 Loans, net of unearned income: Balance at end of period $ 3,988,172 $ 2,398,010 $ 839,823 $ 931,803 $ 2,398,890 $ 10,556,698 Balance at end of period individually evaluated for impairment 7,357 3,276 — — 706 11,339 Balance at end of period collectively evaluated for impairment 3,965,754 2,392,172 839,823 931,643 2,396,477 10,525,869 Balance at end of period acquired with deteriorated credit quality 15,061 2,562 — 160 1,707 19,490 A summary of changes in the allowance for credit losses for covered loans, by loan portfolio type, for the nine months ended September 30, is as follows: 2015 Commercial Real Estate Commercial and Industrial Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 24,072 $ 1,235 $ 6,286 $ 13,171 $ 44,764 Provision for loan losses 217 152 841 101 1,311 (Decrease) Increase in FDIC loss share receivable 748 59 (277 ) (1,872 ) (1,342 ) Transfer of balance to OREO — (1 ) (339 ) (17 ) (357 ) Transfer of balance to non-covered (20,763 ) (1,445 ) — (6,492 ) (28,700 ) Loans charged off (1,188 ) — — — (1,188 ) Recoveries — — 8 — 8 Allowance for loans losses at end of period $ 3,086 $ — $ 6,519 $ 4,891 $ 14,496 Allowance on loans individually evaluated for impairment $ — $ — $ — $ — $ — Allowance on loans collectively evaluated for impairment 3,086 — 6,519 4,891 14,496 Loans, net of unearned income: Balance at end of period $ 43,590 $ 11,419 $ 119,926 $ 78,606 $ 253,541 Balance at end of period individually evaluated for impairment — — — — — Balance at end of period collectively evaluated for impairment 25,014 10,852 94,826 70,548 201,240 Balance at end of period acquired with deteriorated credit quality 18,576 567 25,100 8,058 52,301 2014 Commercial Real Estate Commercial and Industrial Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 38,772 $ 5,380 $ 10,889 $ 16,134 $ 71,175 Provision for loan losses 2,544 376 971 834 4,725 (Decrease) Increase in FDIC loss share receivable 734 609 (2,911 ) 2,721 1,153 Transfer of balance to OREO (1,874 ) (1,162 ) (648 ) (1,487 ) (5,171 ) Loans charged off (9,578 ) (2,192 ) (90 ) (963 ) (12,823 ) Recoveries 38 — — — 38 Allowance for loans losses at end of period $ 30,636 $ 3,011 $ 8,211 $ 17,239 $ 59,097 Allowance on loans individually evaluated for impairment $ — $ — $ — $ — $ — Allowance on loans collectively evaluated for impairment 30,636 3,011 8,211 17,239 59,097 Loans, net of unearned income: Balance at end of period $ 247,156 $ 34,234 $ 130,976 $ 111,823 $ 524,189 Balance at end of period individually evaluated for impairment — — — — — Balance at end of period collectively evaluated for impairment 242,478 33,614 106,672 95,124 477,888 Balance at end of period acquired with deteriorated credit quality 4,678 620 24,304 16,699 46,301 Credit Quality The Company’s investment in non-covered loans by credit quality indicator is presented in the following tables. Because of the difference in accounting for acquired loans, the tables below further segregate the Company’s non-covered loans between acquired loans and loans that were not acquired. Loan premiums/discounts in the tables below represent the adjustment of non-covered acquired loans to fair value at the acquisition date, as adjusted for income accretion and changes in cash flow estimates in subsequent periods. Asset risk classifications for commercial loans reflect the classification as of September 30, 2015 and December 31, 2014 . Credit quality information in the tables below includes loans acquired at the gross loan balance, prior to the application of premiums/discounts, at September 30, 2015 and December 31, 2014 . Legacy loans September 30, 2015 December 31, 2014 (Dollars in thousands) Pass Special Mention Sub-standard Doubtful Loss Total Pass Special Mention Sub-standard Doubtful Total Commercial real estate - Construction $ 557,603 $ 100 $ 1,503 $ — $ 2 $ 559,208 $ 483,930 $ 240 $ 69 $ — $ 484,239 Commercial real estate - Other 3,699,714 24,473 37,874 454 — 3,762,515 3,120,370 49,847 22,193 162 3,192,572 Commercial and industrial 2,732,122 18,821 27,763 579 218 2,779,503 2,414,293 7,330 28,965 1,933 2,452,521 Energy-related 656,525 15,827 41,583 — — 713,935 872,842 — 24 — 872,866 Total $ 7,645,964 $ 59,221 $ 108,723 $ 1,033 $ 220 $ 7,815,161 $ 6,891,435 $ 57,417 $ 51,251 $ 2,095 $ 7,002,198 Legacy loans September 30, 2015 December 31, 2014 (Dollars in thousands) Current 30+ Days Past Due Total Current 30+ Days Past Due Total Residential mortgage $ 640,927 $ 19,616 $ 660,543 $ 508,789 $ 18,905 $ 527,694 Consumer - Home equity 1,480,368 8,428 1,488,796 1,278,865 12,111 1,290,976 Consumer - Indirect automobile 277,996 3,526 281,522 392,504 4,262 396,766 Consumer - Credit card 76,018 698 76,716 71,297 1,448 72,745 Consumer - Other 454,361 2,159 456,520 375,853 2,482 378,335 Total $ 2,929,670 $ 34,427 $ 2,964,097 $ 2,627,308 $ 39,208 $ 2,666,516 Non-covered acquired loans September 30, 2015 December 31, 2014 (Dollars in thousands) Pass Special Mention Sub- standard Doubtful Loss Discount Total Pass Special Mention Sub- standard Doubtful Discount Total Commercial real estate-Construction $ 114,684 $ 1,226 $ 8,538 $ 861 $ — $ (1,548 ) $ 123,761 $ 24,118 $ 2,006 $ 4,624 $ — $ (1,170 ) $ 29,578 Commercial real estate - Other 1,434,860 23,421 69,084 3,256 — (39,944 ) 1,490,677 443,450 12,794 49,139 — (39,119 ) 466,264 Commercial and industrial 498,286 3,671 12,905 1,022 539 (4,374 ) 512,049 86,213 1,861 4,807 257 (5,224 ) 87,914 Energy-related 3,358 771 1,392 — — — 5,521 7,731 — 11 — — 7,742 Total $ 2,051,188 $ 29,089 $ 91,919 $ 5,139 $ 539 $ (45,866 ) $ 2,132,008 $ 561,512 $ 16,661 $ 58,581 $ 257 $ (45,513 ) $ 591,498 Non-covered acquired loans September 30, 2015 December 31, 2014 (Dollars in thousands) Current 30+ Days Past Due Premium (discount) Total Current 30+ Days Past Due Premium (discount) Total Residential mortgage $ 407,673 $ 6,401 $ (4,602 ) $ 409,472 $ 418,552 $ 11,858 $ (5,831 ) $ 424,579 Consumer - Home equity 452,928 7,381 (10,644 ) 449,665 216,310 9,808 (8,419 ) 217,699 Consumer - Indirect automobile 142 24 (39 ) 127 393 39 (40 ) 392 Consumer - Other 95,353 1,355 (3,760 ) 92,948 94,315 3,520 (4,217 ) 93,618 Total $ 956,096 $ 15,161 $ (19,045 ) $ 952,212 $ 729,570 $ 25,225 $ (18,507 ) $ 736,288 The Company’s investment in covered loans by credit quality indicator is presented in the following table. Loan premiums/discounts in the tables below represent the adjustment of covered loans to net book value before allowance at the reporting date. Covered loans September 30, 2015 December 31, 2014 (Dollars in thousands) Pass Special Mention Sub- standard Doubtful Total Pass Special Mention Sub- standard Doubtful Total Commercial real estate - Construction $ 113 $ 820 $ 23 $ 1,091 $ 2,047 $ 34,731 $ 1,928 $ 8,008 $ — $ 44,667 Commercial real estate - Other 25,820 1,922 22,705 754 51,201 87,509 20,422 51,252 — 159,183 Commercial and industrial 5,637 810 6,846 2,358 15,651 23,380 395 9,275 — 33,050 $ 31,570 $ 3,552 $ 29,574 $ 4,203 $ 68,899 $ 145,620 $ 22,745 $ 68,535 $ — $ 236,900 Discount (13,890 ) (16,514 ) Total $ 55,009 $ 220,386 Covered loans September 30, 2015 December 31, 2014 30+ Days Premium 30+ Days Premium (Dollars in thousands) Current Total Current Total Residential mortgage $ 128,804 $ 20,672 $ (29,550 ) $ 119,926 $ 140,628 $ 22,058 $ (34,662 ) $ 128,024 Consumer - Home equity 85,772 9,643 (18,189 ) 77,226 99,478 16,542 (23,590 ) 92,430 Consumer - Credit card 542 27 — 569 614 34 — 648 Consumer - Other 216 15 580 811 337 18 2,701 3,056 Total $ 215,334 $ 30,357 $ (47,159 ) $ 198,532 $ 241,057 $ 38,652 $ (55,551 ) $ 224,158 Legacy Impaired Loans Information on the Company’s investment in legacy impaired loans is presented in the following tables as of and for the periods indicated. September 30, 2015 December 31, 2014 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 16,491 $ 16,491 $ — $ 6,680 $ 6,680 $ — Commercial and industrial 20,360 20,360 — 2,483 2,483 — Energy-related 3,384 3,384 — — — — Consumer - Home equity 214 214 — 682 682 — With an allowance recorded: Commercial real estate 10,681 11,566 (885 ) 1,044 1,069 (25 ) Commercial and industrial 1,009 1,829 (820 ) 1,209 1,617 (408 ) Energy-related 91 94 (3 ) 27 27 — Residential mortgage 14,808 14,879 (71 ) 14,111 14,363 (252 ) Consumer - Home equity 5,248 5,278 (30 ) 7,121 7,165 (44 ) Consumer - Indirect automobile 1,120 1,129 (9 ) 1,410 1,419 (9 ) Consumer - Credit card 329 335 (6 ) 1,012 1,032 (20 ) Consumer - Other 895 920 (25 ) 781 790 (9 ) Total $ 74,630 $ 76,479 $ (1,849 ) $ 36,560 $ 37,327 $ (767 ) Total commercial loans $ 52,016 $ 53,724 $ (1,708 ) $ 11,443 $ 11,876 $ (433 ) Total mortgage loans 14,808 14,879 (71 ) 14,111 14,363 (252 ) Total consumer loans 7,806 7,876 (70 ) 11,006 11,088 (82 ) Three Months Ended Three Months Ended Nine Months Ended Nine Months Ended Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Interest Average Interest (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 16,018 $ 37 $ 7,026 $ 6 $ 16,036 $ 79 7,114 20 Commercial and industrial 20,055 159 3,553 11 20,630 465 4,417 48 Energy-related 3,409 — — — 3,425 — — — Consumer - Home equity 215 3 692 — 204 4 700 14 With an allowance recorded: Commercial real estate 11,649 128 1,631 — 8,247 385 1,533 91 Commercial and industrial 2,121 — 312 — 2,634 — 584 9 Energy-related 99 — — — 106 — — — Residential mortgage 15,008 — 17,305 — 15,100 — 16,341 119 Consumer - Home equity 5,344 — 7,177 5 5,462 — 7,404 40 Consumer - Indirect automobile 1,361 — 1,544 — 1,551 — 1,720 27 Consumer - Credit card 721 — 1,051 — 1,038 — 724 — Consumer - Other 1,030 — 470 — 1,068 — 489 11 Total $ 77,030 $ 327 $ 40,761 $ 22 $ 75,501 $ 933 $ 41,026 $ 379 Total commercial loans $ 53,351 $ 324 $ 12,522 $ 17 $ 51,078 $ 929 $ 13,648 168 Total mortgage loans 15,008 — 17,305 — 15,100 — 16,341 119 Total consumer loans 8,671 3 10,934 5 9,323 4 11,037 92 As of September 30, 2015 and December 31, 2014 , the Company was not committed to lend a material amount of additional funds to any customer whose loan was classified as impaired or as a troubled debt restructuring.

Loss Sharing Agreements and FDI

Loss Sharing Agreements and FDIC Loss Share Receivable	9 Months Ended
	Sep. 30, 2015
Loss Sharing Agreements and FDIC Loss Share Receivable [Abstract]
Loss Sharing Agreements and FDIC Loss Share Receivable	LOSS SHARING AGREEMENTS AND FDIC LOSS SHARE RECEIVABLE Loss Sharing Agreements Since 2009, the Company has acquired certain assets and liabilities of six failed banks. Substantially all of the loans and foreclosed real estate acquired through these transactions are covered by loss share agreements between the FDIC and IBERIABANK, which afford IBERIABANK loss protection. During the reimbursable loss periods, the FDIC will cover 80% of covered loan and foreclosed real estate losses up to certain thresholds for the six acquisitions, and 95% of losses that exceed contractual thresholds for three acquisitions. The reimbursable loss periods, excluding single family residential assets, ended in 2014 for three acquisitions, ended during 2015 for one acquisition and will end during 2016 for two acquisitions. The reimbursable loss period for single family residential assets will end in 2019 for three acquisitions, in 2020 for one acquisition, and in 2021 for two acquisitions. To the extent that loss share coverage ends prior to triggering events on covered assets that would enable the Company to collect these amounts from the FDIC, future impairments may be required. In addition, all covered assets, excluding single family residential assets, have a three year recovery period, which begins upon expiration of the reimbursable loss period. During the recovery periods, the Company must reimburse the FDIC for its share of any recovered losses, net of certain expenses, consistent with the covered loss reimbursement rates in effect during the recovery periods. FDIC loss share receivables The Company recorded indemnification assets in the form of FDIC loss share receivables as of the acquisition date of each of the six banks covered by loss share agreements. At acquisition, the indemnification assets represented the fair value of the expected cash flows to be received from the FDIC under the loss share agreements. Subsequent to acquisition, the FDIC loss share receivables are updated to reflect changes in actual and expected amounts collectible adjusted for amortization. The following is a summary of FDIC loss share receivables year-to-date activity: Nine Months Ended September 30, (Dollars in thousands) 2015 2014 Balance at beginning of period $ 69,627 $ 162,312 Change due to (reversal of) loan loss provision recorded on FDIC covered loans (1,342 ) 1,153 Amortization (19,011 ) (61,393 ) (Submission of reimbursable losses) recoveries payable to the FDIC (4,084 ) 4,901 Impairment — (5,097 ) Changes due to a change in cash flow assumptions on OREO and other changes (1,747 ) (7,164 ) Balance at end of period $ 43,443 $ 94,712 FDIC loss share receivables collectibility assessment The Company assesses the FDIC loss share receivables for collectibility on a quarterly basis. Based on the collectibility analysis completed as of September 30, 2015, the Company concluded that the $43.4 million FDIC loss share receivable is fully collectible as of September 30, 2015 . 2014 Impairment of FDIC loss share receivables Based on improving economic trends, their impact on the amount and timing of expected future cash flows, and delays in the foreclosure process, during the loss share receivable collectibility assessment completed as of September 30, 2014, the Company concluded that certain expected losses were probable of not being collected from either the FDIC or the customer because such projected losses were no longer expected to occur or were expected to occur beyond the reimbursable loss periods specified within the loss share agreements. Management deemed an impairment charge necessary for the nine-month period ended September 30, 2014 for $5.1 million .

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill Changes to the carrying amount of goodwill by reporting unit for the nine months ended September 30, 2015, and the year ended December 31, 2014 are provided in the following table. (Dollars in thousands) IBERIABANK IMC LTC Total Balance, December 31, 2013 $ 373,905 $ 23,178 $ 4,789 $ 401,872 Goodwill acquired during the year 115,278 — 376 115,654 Balance, December 31, 2014 $ 489,183 $ 23,178 $ 5,165 $ 517,526 Goodwill acquired during the period 201,937 — — 201,937 Balance, September 30, 2015 $ 691,120 $ 23,178 $ 5,165 $ 719,463 The goodwill acquired during the first nine months of 2015 is primarily the result of the Florida Bank Group, Old Florida, and Georgia Commerce acquisitions. The goodwill acquired in 2014 was the result of the Trust One-Memphis, Teche, First Private, and The Title Company, LLC acquisitions. See Note 3 and the Annual Report on Form 10-K as of December 31, 2014 for further information on these acquisitions. The Company performed the required annual goodwill impairment test as of October 1, 2014. The Company’s annual impairment test did not indicate impairment in any of the Company’s reporting units as of the testing date. Following the testing date, management periodically evaluated the events and changes that would indicate that goodwill might be impaired and concluded that subsequent interim tests were not necessary. The Company is currently in the process of performing its annual impairment test as of October 1, 2015. Mortgage Servicing Rights Mortgage servicing rights are recorded at the lower of cost or market value in “Other assets” on the Company's consolidated balance sheets and amortized over the remaining servicing life of the loans, with consideration given to prepayment assumptions. Mortgage servicing rights had the following carrying values as of the periods indicated: September 30, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Mortgage servicing rights $ 6,110 $ (2,021 ) $ 4,089 $ 4,751 $ (1,253 ) $ 3,498 Title Plant The Company held title plant assets recorded in "Other assets" on the Company's consolidated balance sheets totaling $6.7 million at both September 30, 2015 and December 31, 2014 . No events or changes in circumstances occurred during the nine months ended September 30, 2015 to suggest the carrying value of the title plant was not recoverable. Intangible assets subject to amortization Definite-lived intangible assets had the following carrying values included in “Other assets” on the Company’s consolidated balance sheets as of the periods indicated: September 30, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Core deposit intangibles $ 77,941 $ (42,195 ) $ 35,746 $ 55,949 $ (36,354 ) $ 19,595 Customer relationship intangible asset 1,348 (946 ) 402 1,348 (822 ) 526 Non-compete agreement 100 (67 ) 33 163 (82 ) 81 Other intangible assets 205 (97 ) 108 205 (46 ) 159 Total $ 79,594 $ (43,305 ) $ 36,289 $ 57,665 $ (37,304 ) $ 20,361

Derivative Instruments and Othe

Derivative Instruments and Other Hedging Activities	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Other Hedging Activities	DERIVATIVE INSTRUMENTS AND OTHER HEDGING ACTIVITIES The Company enters into derivative financial instruments to manage interest rate risk, asset sensitivity, and other exposures such as liquidity and credit risk. The primary types of derivatives used by the Company include interest rate swap agreements, foreign exchange contracts, interest rate lock commitments, forward sales commitments, and written and purchased options. All derivative instruments are recognized on the consolidated balance sheets as other assets or other liabilities at fair value, as required by ASC Topic 815, Derivatives and Hedging . For cash flow hedges, the effective portion of the gain or loss related to the derivative instrument is initially reported as a component of other comprehensive income and subsequently reclassified into earnings when the forecasted transaction affects earnings or when the hedge is terminated. The ineffective portion of the gain or loss is reported in earnings immediately. In applying hedge accounting for derivatives, the Company establishes and documents a method for assessing the effectiveness of the hedging derivative and a measurement approach for determining the ineffective aspect of the hedge upon the inception of the hedge. For derivative instruments that are not designated as hedging instruments, changes in the fair value of the derivatives are recognized in earnings immediately. Information pertaining to outstanding derivative instruments is as follows: (Dollars in thousands) Asset Derivatives Fair Value Liability Derivatives Fair Value Balance Sheet September 30, 2015 December 31, 2014 Balance Sheet September 30, 2015 December 31, 2014 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ — $ — Other liabilities $ 575 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ — $ 575 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ 23,960 $ 15,434 Other liabilities $ 23,960 $ 15,434 Foreign exchange contracts Other assets 4,369 — Other liabilities 4,369 — Forward sales contracts Other assets 452 25 Other liabilities 3,108 2,556 Written and purchased options Other assets 12,659 17,444 Other liabilities 6,135 13,364 Total derivatives not designated as hedging instruments under ASC Topic 815 41,440 32,903 37,572 31,354 Total $ 41,440 $ 32,903 $ 38,147 $ 31,354 (Dollars in thousands) Asset Derivatives Liability Derivatives September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts $ — $ — $ 108,500 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ — $ 108,500 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts $ 565,820 $ 444,703 $ 565,820 $ 444,703 Foreign exchange contracts 4,392 — 4,370 — Forward sales contracts 55,412 15,897 428,547 391,992 Written and purchased options 361,565 362,580 190,186 225,741 Total derivatives not designated as hedging instruments under ASC Topic 815 987,189 823,180 1,188,923 1,062,436 Total $ 987,189 $ 823,180 $ 1,297,423 $ 1,062,436 The Company is party to collateral agreements with certain derivative counterparties. Such agreements require that the Company maintain collateral based on the fair values of individual derivative transactions. In the event of default by the Company, the counterparty would be entitled to the collateral. At September 30, 2015 and December 31, 2014 , the Company was required to post $27.2 million and $11.5 million , respectively, in cash as collateral for its derivative transactions, which are included in interest-bearing deposits in banks on the Company’s consolidated balance sheets. The Company does not anticipate additional assets will be required to be posted as collateral, nor does it believe additional assets would be required to settle its derivative instruments immediately if contingent features were triggered at September 30, 2015 . The Company’s master netting agreements represent written, legally enforceable bilateral agreements that (1) create a single legal obligation for all individual transactions covered by the master agreement and (2) in the event of default, provide the non-defaulting counterparty the right to accelerate, terminate, and close-out on a net basis all transactions under the agreement and to promptly liquidate or set-off collateral posted by the defaulting counterparty. As permitted by U.S. GAAP, the Company does not offset fair value amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral against recognized fair value amounts of derivatives executed with the same counterparty under a master netting agreement. The following table reconciles the gross amounts presented in the consolidated balance sheets to the net amounts that would result in the event of offset. September 30, 2015 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 23,959 — — 23,959 Written and purchased options 6,127 — — 6,127 Total derivative assets subject to master netting arrangements $ 30,086 $ — $ — $ 30,086 Derivative liabilities Interest rate contracts designated as hedging instruments 575 — (508 ) 67 Interest rate contracts not designated as hedging instruments 23,959 — (14,704 ) 9,255 Total derivative liabilities subject to master netting arrangements $ 24,534 $ — $ (15,212 ) $ 9,322 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. December 31, 2014 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 15,411 — — 15,411 Written and purchased options 13,387 — — 13,387 Total derivative assets subject to master netting arrangements $ 28,798 $ — $ — $ 28,798 Derivative liabilities Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 15,411 — (3,735 ) 11,676 Total derivative liabilities subject to master netting arrangements $ 15,411 $ — $ (3,735 ) $ 11,676 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. During the nine months ended September 30, 2015 and 2014 , the Company has not reclassified into earnings any gain or loss as a result of the discontinuance of cash flow hedges because it was probable the original forecasted transaction would not occur by the end of the originally specified term. At September 30, 2015 , the Company does not expect to reclassify any amount from accumulated other comprehensive income into interest income over the next twelve months for derivatives that will be settled. At September 30, 2015 and 2014, and for the three and nine months then ended, information pertaining to the effect of the hedging instruments on the consolidated financial statements is as follows: Location of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Gain (Loss) Recognized in OCI net of taxes (Effective Portion) Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) (Dollars in thousands) For the Three Months Ended September 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2015 2014 2015 2014 2015 2014 Interest rate contracts $ (3,412 ) $ — Other income (expense) $ — $ — Other income (expense) $ — $ — Total $ (3,412 ) $ — $ — $ — $ — $ — Location of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Gain (Loss) Recognized in OCI net of taxes (Effective Portion) Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) (Dollars in thousands) For the Nine Months Ended September 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2015 2014 2015 2014 2015 2014 Interest rate contracts $ (374 ) $ — Other income (expense) $ — $ — Other income (expense) $ — $ (1 ) Total $ (374 ) $ — $ — $ — $ — $ (1 ) Information pertaining to the effect of derivatives not designated as hedging instruments on the consolidated financial statements for the three and nine months ended September 30, 2015 is as follows: (Dollars in thousands) Amount of Gain (Loss) Recognized Location of Gain (Loss) For the Three Months Ended September 30 For the Nine Months Ended September 30 2015 2014 2015 2014 Interest rate contracts Other income $ 1,130 $ 406 $ 3,069 $ 1,971 Forward sales contracts Mortgage income (6,524 ) (3,648 ) 1,526 (7,512 ) Written and purchased options Mortgage income (526 ) 773 (1,711 ) 2,401 Total $ (5,920 ) $ (2,469 ) $ 2,884 $ (3,140 )

Shareholders' Equity, Capital R

Shareholders' Equity, Capital Ratios and Other Regulatory Matters	9 Months Ended
	Sep. 30, 2015
Banking and Thrift [Abstract]
Shareholders' Equity, Capital Ratios and Other Regulatory Matters	SHAREHOLDERS' EQUITY, CAPITAL RATIOS AND OTHER REGULATORY MATTERS During the third quarter of 2015, the Company issued an aggregate of 3,200,000 depositary shares (the “Depositary Shares”), each representing a 1/400th ownership interest in a share of the Company’s 6.625% Fixed-to-Floating Non-Cumulative Perpetual Preferred Stock, Series B, par value $1.00 per share, (“Series B Preferred Stock”), with a liquidation preference of $10,000 per share of Series B Preferred Stock (equivalent to $25 per depositary share) which represents $80,000,000 in aggregate liquidation preference. Dividends will accrue and be payable on the Series B preferred stock, subject to declaration by the Company’s board of directors, from the date of issuance to, but excluding August 1, 2025, at a rate of 6.625% per annum, payable semi-annually, in arrears, and from and including August 1, 2025, dividends will accrue and be payable at a floating rate equal to three-month LIBOR plus a spread of 426.2 basis points, payable quarterly, in arrears. The Company may redeem the Series B preferred stock at its option, subject to regulatory approval, as described in the Prospectus. The Company and IBERIABANK are subject to various regulatory capital requirements administered by the federal and state banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and IBERIABANK, as applicable, must meet specific capital guidelines that involve quantitative measures of their assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. The capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. On January 1, 2015, the Company and IBERIABANK became subject to revised capital adequacy standards as implemented by new final rules approved by the U.S. banking regulatory agencies, including the FRB, to address relevant provisions of the Dodd-Frank Act. Certain provisions of the new rules will be phased in from that date to January 1, 2019. The final rules: • Require that non-qualifying capital instruments, including trust preferred securities and cumulative perpetual preferred stock, must be fully phased out of Tier 1 capital by January 1, 2016, • Establish new qualifying criteria for regulatory capital, including new limitations on the inclusion of deferred tax assets and mortgage servicing rights, • Require a minimum ratio of common equity Tier 1 capital (“CET1”) to risk-weighted assets of 4.5% , • Increase the minimum Tier 1 capital to risk-weighted assets ratio requirements from 4% to 6% , • Implement a new capital conservation buffer requirement for a banking organization to maintain a CET1 capital ratio more than 2.5% above the minimum CET1 capital, Tier 1 capital and total risk-based capital ratios in order to avoid limitations on capital distributions, including dividend payments, and certain discretionary bonus payments to executive officers, with the buffer to be phased in beginning on January 1, 2016 at 0.625% and increasing annually until fully phased in at 2.5% by January 1, 2019. A banking organization with a buffer of less than the required amount would be subject to increasingly stringent limitations on certain distributions and payments as the buffer approaches zero, and • Increase capital requirements for past-due loans, high volatility commercial real estate exposures, and certain short-term commitments and securitization exposures. Management believes that, as of September 30, 2015 , the Company and IBERIABANK met all capital adequacy requirements to which they are subject. As of September 30, 2015 , the most recent notification from the FDIC categorized IBERIABANK as well capitalized under the regulatory framework for prompt corrective action (the prompt corrective action requirements are not applicable to the Company) existing at the time of notification. To be categorized as well capitalized, an institution must maintain minimum total risk-based, Tier 1 risk-based and Tier 1 leverage ratios as set forth in the following table. There are no conditions or events since the notification that management believes have changed that categorization. The Company’s and IBERIABANK’s actual capital amounts and ratios as of September 30, 2015 and December 31, 2014 are presented in the following table. September 30, 2015 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 754,230 4.00 % N/A N/A $ 1,758,666 9.33 % IBERIABANK 751,378 4.00 939,222 5.00 1,647,804 8.77 Common Equity Tier 1 (CET1) (1) Consolidated $ 737,629 4.50 % N/A N/A $ 1,652,078 10.08 % IBERIABANK 735,647 4.50 1,062,601 6.50 1,647,804 10.08 Tier 1 Risk-Based Capital (1) Consolidated $ 983,506 6.00 % N/A N/A $ 1,758,666 10.73 % IBERIABANK 980,863 6.00 1,307,817 8.00 1,647,804 10.08 Total Risk-Based Capital (1) Consolidated $ 1,311,341 8.00 % N/A N/A $ 1,990,821 12.15 % IBERIABANK 1,307,817 8.00 1,634,772 10.00 1,792,584 10.97 December 31, 2014 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 602,387 4.00 % N/A N/A $ 1,408,842 9.36 % IBERIABANK 600,149 4.00 750,186 5.00 1,266,241 8.44 Tier 1 Risk-Based Capital Consolidated $ 504,114 4.00 % N/A N/A $ 1,408,842 11.18 % IBERIABANK 502,421 4.00 753,631 6.00 1,266,241 10.08 Total Risk-Based Capital Consolidated $ 1,008,227 8.00 % N/A N/A $ 1,550,789 12.31 % IBERIABANK 1,004,841 8.00 1,256,052 10.00 1,408,188 11.21 (1) Beginning January 1, 2016, minimum capital ratios will be subject to a capital conservation buffer of 0.625% . This capital conservation buffer will increase in subsequent years by 0.625% annually until it is fully phased in on January 1, 2019 at 2.50% .

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE Share-based payment awards that entitle holders to receive non-forfeitable dividends before vesting are considered participating securities that are included in the calculation of earnings per share using the two-class method. The two-class method is an earnings allocation formula under which earnings per share is calculated for common stock and participating securities according to dividends declared and participating rights in undistributed earnings. Under this method, all earnings, distributed and undistributed, are allocated to common shares and participating securities based on their respective rights to receive dividends. The following table presents the calculation of basic and diluted earnings per share for the periods indicated. Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share data) 2015 2014 2015 2014 Earnings per common share - basic Net income $ 42,475 $ 30,893 $ 98,437 $ 69,445 Dividends and undistributed earnings allocated to unvested restricted shares (492 ) (462 ) (1,171 ) (1,114 ) Net income allocated to common shareholders - basic $ 41,983 $ 30,431 $ 97,266 $ 68,331 Weighted average common shares outstanding 40,514 32,803 37,436 30,791 Earnings per common share - basic $ 1.04 $ 0.93 $ 2.60 $ 2.22 Earnings per common share - diluted Net income allocated to common shareholders - basic $ 41,983 $ 30,431 $ 97,266 $ 68,331 Dividends and undistributed earnings allocated to unvested restricted shares (3 ) (4 ) (41 ) (24 ) Net income allocated to common shareholders - diluted $ 41,980 $ 30,427 $ 97,225 $ 68,307 Weighted average common shares outstanding 40,514 32,803 37,436 30,791 Dilutive potential common shares - stock options 100 124 96 132 Weighted average common shares outstanding - diluted 40,614 32,927 37,532 30,923 Earnings per common share - diluted $ 1.03 $ 0.92 $ 2.59 $ 2.21 For the three months ended September 30, 2015 , and 2014 , the calculations for basic shares outstanding exclude the weighted average shares owned by the Recognition and Retention Plan (“RRP”) of 616,307 , and 621,341 , respectively. For the nine months ended September 30, 2015, and 2014, basic shares outstanding exclude 606,621 and 630,320 shares owned by the RRP, respectively. The effects from the assumed exercises of 82,310 , and 12,765 stock options were not included in the computation of diluted earnings per share for the three months ended September 30, 2015 , and 2014 , respectively, because such amounts would have had an antidilutive effect on earnings per common share. For the nine months ended September 30, 2015, and 2014, the effects from the assumed exercise of 79,690 and 12,765 stock options, respectively, were not included in the computation of diluted earnings per share because such amounts would have had an antidilutive effect on earnings per common share.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	SHARE-BASED COMPENSATION The Company has various types of share-based compensation plans that permit the granting of awards in the form of stock options, restricted stock, restricted share units, phantom stock and performance units. These plans are administered by the Compensation Committee of the Board of Directors, which selects persons eligible to receive awards and determines the terms, conditions and other provisions of the awards. At September 30, 2015 , awards of 788,196 shares could be made under approved incentive compensation plans. Stock option awards The Company issues stock options under various plans to directors, officers and other key employees. The option exercise price cannot be less than the fair value of the underlying common stock as of the date of the option grant and the maximum option term cannot exceed ten years. The following table represents the activity related to stock options during the periods indicated: Number of shares Weighted Average Exercise Price Outstanding options, December 31, 2014 867,682 $ 55.92 Granted 81,313 62.53 Exercised (95,265 ) 50.64 Forfeited or expired (15,733 ) 66.57 Outstanding options, September 30, 2015 837,997 $ 56.96 Exercisable options, September 30, 2015 570,148 $ 56.53 Outstanding options, December 31, 2013 1,072,829 $ 53.47 Granted 77,098 65.30 Exercised (234,363 ) 48.36 Forfeited or expired (13,446 ) 60.82 Outstanding options, September 30, 2014 902,118 $ 55.70 Exercisable options, September 30, 2014 581,423 $ 55.65 The Company uses the Black-Scholes option pricing model to estimate the fair value of stock option awards. The following weighted-average assumptions were used for option awards issued during the nine-month periods ended September 30: 2015 2014 Expected dividends 2.2 % 2.1 % Expected volatility 35.6 % 35.8 % Risk-free interest rate 2.0 % 2.3 % Expected term (in years) 7.5 7.5 Weighted-average grant-date fair value $ 19.60 $ 21.25 The assumptions above are based on multiple factors, including historical stock option exercise patterns and post-vesting employment termination behaviors, expected future exercise patterns and the expected volatility of the Company’s stock price. The following table represents the compensation expense that is included in non-interest expense in the accompanying consolidated statements of comprehensive income related to stock options for the three-month and nine-month periods ended September 30: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2015 2014 2015 2014 Compensation expense related to stock options $ 455 $ 508 $ 1,400 $ 1,545 At September 30, 2015 , there was $3.1 million of unrecognized compensation cost related to stock options that is expected to be recognized over a weighted-average period of 5.2 years. Restricted stock awards The Company issues restricted stock under various plans for certain officers and directors. The restricted stock awards may not be sold or otherwise transferred until certain restrictions have lapsed. The holders of the restricted stock receive dividends and have the right to vote the shares. The compensation expense for these awards is determined based on the market price of the Company’s common stock at the date of grant applied to the total number of shares granted and is recognized over the vesting period. As of September 30, 2015 and 2014 , unrecognized share-based compensation associated with these awards totaled $22.2 million for both periods. Restricted share units During the first nine months of 2015 and 2014 , the Company issued restricted share units to certain of its executive officers. Restricted share units vest after the end of a three -year performance period, based on satisfaction of the market and performance conditions set forth in the restricted share unit agreement. Recipients do not possess voting or investment power over the common stock underlying such units until vesting. The grant date fair value of these restricted share units is the same as the value of the corresponding number of shares of common stock, adjusted for assumptions surrounding the market-based conditions contained in the respective agreements. The following table represents the compensation expense that was included in non-interest expense in the accompanying consolidated statements of comprehensive income related to restricted stock awards and restricted share units for the three-month and nine-month periods ended September 30: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2015 2014 2015 2014 Compensation expense related to restricted stock awards and restricted share units $ 2,935 $ 2,497 $ 8,739 $ 7,382 The following table represents unvested restricted stock award and restricted share unit activity for the nine months ended September 30: 2015 2014 Balance at beginning of period 506,289 523,756 Granted 203,762 165,634 Forfeited (23,471 ) (18,171 ) Earned and issued (170,513 ) (152,112 ) Balance at end of period 516,067 519,107 Phantom stock awards The Company issues phantom stock awards to certain key officers and employees. The awards are subject to a vesting period of five to seven years and are paid out in cash upon vesting. The amount paid per vesting period is calculated as the number of vested “share equivalents” multiplied by the closing market price of a share of the Company’s common stock on the vesting date. Share equivalents are calculated on the date of grant as the total award’s dollar value divided by the closing market price of a share of the Company’s common stock on the grant date. Award recipients are also entitled to a “dividend equivalent” on each unvested share equivalent held by the award recipient. A dividend equivalent is a dollar amount equal to the cash dividends that the participant would have been entitled to receive if the participant’s share equivalents were issued in shares of common stock. Dividend equivalents are reinvested as share equivalents that will vest and be paid out on the same date as the underlying share equivalents on which the dividend equivalents were paid. The number of share equivalents acquired with a dividend equivalent is determined by dividing the aggregate of dividend equivalents paid on the unvested share equivalents by the closing price of a share of the Company’s common stock on the dividend payment date. Performance units During the first nine months of 2015 and 2014 , the Company issued shares of performance units to certain of its executive officers. Performance units are tied to the value of shares of the Company’s common stock, are payable in cash, and vest in increments of one-third per year after attainment of one or more performance measures. The value of performance units is the same as the value of the corresponding number of shares of common stock. The following table indicates compensation expense recorded for phantom stock and performance units based on the number of share equivalents vested at September 30 of the periods indicated and the current market price of the Company’s stock at that time: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2015 2014 2015 2014 Compensation expense related to phantom stock and performance units $ 2,976 $ 619 $ 9,482 $ 3,692 The following table represents phantom stock award and performance unit activity during the periods indicated: Number of share equivalents Dividend equivalents Total share equivalents Value of share equivalents (1) Balance, December 31, 2014 460,212 22,648 482,860 $ 31,313,000 Granted 156,505 7,261 163,766 9,533,000 Forfeited share equivalents (29,180 ) (1,541 ) (30,721 ) (1,788,000 ) Vested share equivalents (130,380 ) (9,134 ) (139,514 ) (8,829,000 ) Balance, September 30, 2015 457,157 19,234 476,391 $ 27,731,000 Balance, December 31, 2013 417,238 22,351 439,589 $ 27,628,000 Granted 115,620 7,147 122,767 7,674,000 Forfeited share equivalents (19,498 ) (1,751 ) (21,249 ) (1,328,000 ) Vested share equivalents (68,480 ) (6,615 ) (75,095 ) (5,002,000 ) Balance, September 30, 2014 444,880 21,132 466,012 $ 29,130,000 (1) Except for share equivalents at the beginning of each period, which are based on the value at that time, and vested share payments, which are based on the cash paid at the time of vesting, the value of share equivalents is calculated based on the market price of the Company’s stock at the end of the respective periods. The market price of the Company’s stock was $58.21 and $62.51 on September 30, 2015 , and 2014 , respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value guidance establishes a framework for using fair value to measure assets and liabilities. The Company estimates fair value based on the assumptions market participants would use when selling an asset or transferring a liability and characterizes such measurements within the fair value hierarchy based on the inputs used to develop those assumptions and measure fair value. The hierarchy requires the Company to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: • Level 1 - Quoted prices in active markets for identical assets or liabilities. • Level 2 - Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. A description of the valuation methodologies used for instruments measured at fair value follows, as well as the classification of such instruments within the valuation hierarchy. Recurring fair value measurements Securities available for sale Securities are classified within Level 1 where quoted market prices are available in an active market. Inputs include securities that have quoted prices in active markets for identical assets. If quoted market prices are unavailable, fair value is estimated using quoted prices of securities with similar characteristics, at which point the securities would be classified within Level 2 of the hierarchy. Mortgage loans held for sale Mortgage loans originated and held for sale are recorded at fair value under the fair value option and are based on quotes or bids received directly from the purchasing financial institutions (Level 2). Derivative financial instruments The Company enters into commitments to originate loans whereby the interest rate on the prospective loan is determined prior to funding. Rate locks on mortgage loans that are intended to be sold are considered to be derivatives. The Company offers its customers a certificate of deposit that provides the purchaser a guaranteed return of principal at maturity plus potential return, which allows the Company to identify a known cost of funds. The rate of return is based on an equity index, and as such represents an embedded derivative. Fair value of interest rate swaps, interest rate locks, foreign exchange contracts, forward sales commitments, and equity-linked written and purchased options are estimated using prices of financial instruments with similar characteristics, and thus are classified within Level 2 of the fair value hierarchy. The Company has segregated all financial assets and liabilities that are measured at fair value on a recurring basis into the most appropriate level within the fair value hierarchy based on the inputs used to estimate the fair value at the measurement date in the tables below. September 30, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,827,805 $ — $ 2,827,805 Mortgage loans held for sale — 202,168 — 202,168 Derivative instruments — 41,440 — 41,440 Total $ — $ 3,071,413 $ — $ 3,071,413 Liabilities Derivative instruments $ — $ 38,147 $ — $ 38,147 Total $ — $ 38,147 $ — $ 38,147 December 31, 2014 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,158,853 $ — $ 2,158,853 Mortgage loans held for sale — 139,950 — 139,950 Derivative instruments — 32,903 — 32,903 Total $ — $ 2,331,706 $ — $ 2,331,706 Liabilities Derivative instruments $ — $ 31,354 $ — $ 31,354 Total $ — $ 31,354 $ — $ 31,354 During the nine months ended September 30, 2015 there were no transfers between the Level 1 and Level 2 fair value categories. Gains and losses (realized and unrealized) included in earnings (or accumulated other comprehensive income) during the first nine months of 2015 related to assets and liabilities measured at fair value on a recurring basis are reported in non-interest income or other comprehensive income as follows: (Dollars in thousands) Non-interest Other Net gains included in earnings $ 2,643 $ — Change in unrealized net gains relating to assets still held at September 30, 2015 — 9,458 Non-recurring fair value measurements Other real estate owned (OREO) Fair values of OREO are determined by sales agreement or appraisal, and costs to sell are based on estimation per the terms and conditions of the sales agreement or amounts commonly used in real estate transactions. Inputs include appraisal values on the properties or recent sales activity for similar assets in the property’s market, and thus OREO measured at fair value would be classified within Level 2 of the hierarchy. The Company included property write-downs of $3.4 million and $ 1.9 million in earnings for the nine -month periods ending September 30, 2015 and 2014 , respectively. The Company has segregated all financial assets and liabilities that are measured at fair value on a non-recurring basis into the most appropriate level within the fair value hierarchy based on the inputs used to determine the fair value at the measurement date in the tables below. September 30, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets OREO, net $ — $ 1,904 $ — $ 1,904 Total $ — $ 1,904 $ — $ 1,904 December 31, 2014 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets OREO, net $ — $ 1,483 $ — $ 1,483 Total $ — $ 1,483 $ — $ 1,483 The tables above exclude the initial measurement of assets and liabilities that were acquired as part of the acquisitions completed in 2014 through the third quarter of 2015. These assets and liabilities were recorded at their fair value upon acquisition in accordance with U.S. GAAP and were not re-measured during the periods presented unless specifically required by U.S. GAAP. Acquisition date fair values represent either Level 2 fair value measurements (investment securities, OREO, property, equipment, and debt) or Level 3 fair value measurements (loans, deposits, and core deposit intangible asset). The Company did not record any liabilities at fair value for which measurement of the fair value was made on a non-recurring basis at September 30, 2015 and December 31, 2014 . Fair value option The Company has elected the fair value option for certain originated residential mortgage loans held for sale, which allows for a more effective offset of the changes in fair values of the loans and the derivative instruments used to hedge them without the burden of complying with the requirements for hedge accounting. The following table summarizes the difference between the aggregate fair value and the aggregate unpaid principal balance for mortgage loans held for sale measured at fair value: September 30, 2015 December 31, 2014 (Dollars in thousands) Aggregate Aggregate Aggregate Aggregate Aggregate Aggregate Mortgage loans held for sale, at fair value $ 202,168 $ 194,376 $ 7,792 $ 139,950 $ 134,639 $ 5,311 Interest income on mortgage loans held for sale is recognized based on contractual rates and is reflected in interest income on loans held for sale in the consolidated statements of comprehensive income. Net gains resulting from the change in fair value of these loans that were recorded in mortgage income in the consolidated statements of comprehensive income for the three and nine months ended September 30, 2015 totaled $0.6 million and $ 2.4 million , respectively. Net losses resulting from the change in fair value of these loans totaled $1.6 million for the three months ended September 30, 2014 , while net gains totaled $4.0 million for the nine months ended September 30, 2014 . The changes in fair value are mostly offset by economic hedging activities, with an immaterial portion of these changes attributable to changes in instrument-specific credit risk.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	FAIR VALUE OF FINANCIAL INSTRUMENTS The estimated fair value of a financial instrument is the current amount that would be exchanged between willing parties, other than in a forced liquidation. Fair value is best determined based upon quoted market prices. However, in many instances, there are no quoted market prices for the Company’s various financial instruments. In cases where quoted market prices are not available, fair values are based on estimates using present value or other valuation techniques. Those techniques are significantly affected by the assumptions used, including the discount rate and estimates of future cash flows. Accordingly, the fair value estimates may not be realized in an immediate settlement of the instrument. ASC Topic 825, Financial Instruments , excludes certain financial instruments and all non-financial instruments from its disclosure requirements. Consequently, the aggregate fair value amounts presented may not necessarily represent the underlying fair value of the Company. The following methods and assumptions were used to estimate the fair value of each class of financial instruments for which it is practicable to estimate that value. Refer to Note 13 to these consolidated financial statements for the methods and assumptions used to measure the fair value of investment securities and derivative instruments. Cash and cash equivalents The carrying amounts of cash and cash equivalents approximate their fair values. Loans The fair values of non-covered mortgage loans are estimated based on present values using entry-value rates (the interest rate that would be charged for a similar loan to a borrower with similar risk at the indicated balance sheet date) at September 30, 2015 and December 31, 2014 , weighted for varying maturity dates. Other non-covered loans are valued based on present values using entry-value interest rates at September 30, 2015 and December 31, 2014 applicable to each category of loans, which would be classified within Level 3 of the hierarchy. Fair values of mortgage loans held for sale are based on commitments on hand from investors or prevailing market prices, a Level 2 measurement. Covered loans are measured using projections of expected cash flows, exclusive of the loss sharing agreements with the FDIC. Fair value of the covered loans included in the table below reflects the current fair value of these loans, which is based on an updated estimate of the projected cash flow as of the dates indicated. The fair value associated with the loans includes estimates related to expected prepayments and the amount and timing of undiscounted expected principal, interest and other cash flows, which also would be classified within Level 3 of the hierarchy. FDIC Loss Share Receivables The fair value is determined using projected cash flows from loss sharing agreements based on expected reimbursements for losses at the applicable loss sharing percentages based on the terms of the loss share agreements. Cash flows are discounted to reflect the timing and receipt of the loss sharing reimbursements from the FDIC. The fair value of the Company’s FDIC loss share receivable would be categorized within Level 3 of the hierarchy. Deposits The fair values of NOW accounts, money market deposits and savings accounts are the amounts payable on demand at the reporting date. Certificates of deposit were valued using a discounted cash flow model based on the weighted-average rate at September 30, 2015 and December 31, 2014 for deposits with similar remaining maturities. The fair value of the Company’s deposits would therefore be categorized within Level 3 of the hierarchy. Short-term borrowings The carrying amounts of short-term borrowings maturing within ninety days approximate their fair values. Long-term debt The fair values of long-term debt are estimated using discounted cash flow analyses based on the Company’s current incremental borrowing rates for similar types of borrowing arrangements. The fair value of the Company’s long-term debt would therefore be categorized within Level 3 of the fair value hierarchy. Off-balance sheet items The Company has outstanding commitments to extend credit and standby letters of credit. These off-balance sheet financial instruments are generally exercisable at the market rate prevailing at the date the underlying transaction will be completed. At September 30, 2015 and December 31, 2014 , the fair value of guarantees under commercial and standby letters of credit was immaterial. The carrying amount and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments are as follows: September 30, 2015 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 682,272 $ 682,272 $ 682,272 $ — $ — Investment securities 2,926,135 2,928,416 — 2,928,416 — Loans and loans held for sale, net of unearned income and allowance for loan losses 14,188,933 14,637,107 — 212,764 14,424,343 FDIC loss share receivables 43,443 8,437 — — 8,437 Derivative instruments 41,440 41,440 — 41,440 — Financial Liabilities Deposits $ 16,303,065 $ 15,996,499 $ — $ — $ 15,996,499 Short-term borrowings 222,460 222,460 222,460 — — Long-term debt 341,973 311,982 — — 311,982 Derivative instruments 38,147 38,147 — 38,147 — December 31, 2014 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 548,095 $ 548,095 $ 548,095 $ — $ — Investment securities 2,275,813 2,278,334 — 2,278,334 — Loans and loans held for sale, net of unearned income and allowance for loan losses 11,450,985 11,475,315 — 139,950 11,335,365 FDIC loss share receivables 69,627 19,606 — — 19,606 Derivative instruments 32,903 32,903 — 32,903 — Financial Liabilities Deposits $ 12,520,525 $ 12,298,017 $ — $ — $ 12,298,017 Short-term borrowings 845,742 845,742 845,742 — — Long-term debt 403,254 376,139 — — 376,139 Derivative instruments 31,354 31,354 — 31,354 — The fair value estimates presented herein are based upon pertinent information available to management as of September 30, 2015 and December 31, 2014 . Although management is not aware of any factors that would significantly affect the estimated fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since that date and, therefore, current estimates of fair value may differ significantly from the amounts presented herein.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS Each of the Company’s reportable operating segments is a business unit that serves the specific needs of the Company’s customers based on the products and services it offers. The reportable segments are based upon those revenue-producing components for which separate financial information is produced internally and are subject to evaluation by the chief operating decision maker in deciding how to allocate resources to segments. The Company reports the results of its operations through three business segments: IBERIABANK, IMC, and LTC. The IBERIABANK segment represents the Company’s commercial and retail banking functions including its lending, investment, and deposit activities. IBERIABANK also includes the Company’s wealth management, capital markets, and other corporate functions that are not specifically related to a strategic business unit. The IMC segment represents the Company’s origination, funding and subsequent sale of one-to-four family residential mortgage loans. The LTC segment represents the Company’s title insurance and loan closing services. Certain expenses not directly attributable to a specific reportable segment are allocated to segments based on pre-determined means that reflect utilization. Also within IBERIABANK are certain reconciling items in order to translate reportable segment results into consolidated results. The following tables present certain information regarding our operations by reportable segment, including a reconciliation of segment results to reported consolidated results for the periods presented. Reconciling items between segment results and reported results include: • Elimination of interest income and interest expense representing interest earned by IBERIABANK on interest-bearing checking accounts held by related companies, as well as the elimination of the related deposit balances at the IBERIABANK segment; • Elimination of investment in subsidiary balances on certain operating segments included in total and average segment assets; and • Elimination of intercompany due to and due from balances on certain operating segments that are included in total and average segment assets. Three Months Ended September 30, 2015 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 169,005 $ 2,071 $ 1 $ 171,077 Interest expense 15,109 851 — 15,960 Net interest income 153,896 1,220 1 155,117 Provision for loan losses 5,062 — — 5,062 Mortgage income 365 20,365 — 20,730 Title revenue — — 6,627 6,627 Other non-interest income 30,120 1 — 30,121 Allocated expenses (3,518 ) 2,693 825 — Non-interest expense 124,909 15,605 4,454 144,968 Income before income tax expense 57,928 3,288 1,349 62,565 Income tax expense 18,253 1,306 531 20,090 Net income $ 39,675 $ 1,982 $ 818 $ 42,475 Total loans and loans held for sale $ 14,094,936 $ 224,251 $ — $ 14,319,187 Total assets 19,242,690 264,914 26,621 19,534,225 Total deposits 16,293,681 9,384 — 16,303,065 Average assets 19,321,164 256,897 26,009 19,604,070 Three Months Ended September 30, 2014 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 131,987 $ 1,805 $ 1 $ 133,793 Interest expense 11,416 626 — 12,042 Net interest income 120,571 1,179 1 121,751 Provision for loan losses 5,621 93 — 5,714 Mortgage income (4 ) 14,267 — 14,263 Title revenue — — 5,577 5,577 Other non-interest income 27,310 (36 ) (2 ) 27,272 Allocated expenses (2,386 ) 1,697 689 — Non-interest expense 104,172 11,624 4,316 120,112 Income before income tax expense 40,470 1,996 571 43,037 Income tax expense 11,128 785 231 12,144 Net income $ 29,342 $ 1,211 $ 340 $ 30,893 Total loans and loans held for sale $ 11,057,497 $ 171,920 $ — $ 11,229,417 Total assets 15,288,142 200,778 25,529 15,514,449 Total deposits 12,371,522 6,169 — 12,377,691 Average assets 15,240,567 210,345 25,296 15,476,208 Nine Months Ended September 30, 2015 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 464,775 $ 5,430 $ 2 $ 470,207 Interest expense 41,410 2,199 — 43,609 Net interest income 423,365 3,231 2 426,598 Provision for loan losses 19,197 — — 19,197 Mortgage income 932 63,067 — 63,999 Title revenue — — 17,402 17,402 Other non-interest income 86,498 (2 ) (7 ) 86,489 Allocated expenses (11,603 ) 8,685 2,918 — Non-interest expense 373,948 44,259 13,123 431,330 Income before income tax expense 129,253 13,352 1,356 143,961 Income tax expense 39,695 5,286 543 45,524 Net income $ 89,558 $ 8,066 $ 813 $ 98,437 Total loans and loans held for sale $ 14,094,936 $ 224,251 $ — $ 14,319,187 Total assets 19,242,690 264,914 26,621 19,534,225 Total deposits 16,293,681 9,384 — 16,303,065 Average assets 17,760,033 230,379 25,268 18,015,680 Nine Months Ended September 30, 2014 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 362,974 $ 4,563 $ 2 $ 367,539 Interest expense 30,784 1,323 — 32,107 Net interest income 332,190 3,240 2 335,432 Provision for loan losses 12,481 84 — 12,565 Mortgage income 80 38,070 — 38,150 Title revenue — — 15,007 15,007 Other non-interest income 73,459 (60 ) (2 ) 73,397 Allocated expenses (9,110 ) 6,432 2,678 — Non-interest expense 308,515 33,558 12,406 354,479 Income (loss) before income tax expense 93,843 1,176 (77 ) 94,942 Income tax expense (benefit) 25,038 473 (14 ) 25,497 Net income (loss) $ 68,805 $ 703 $ (63 ) $ 69,445 Total loans and loans held for sale $ 11,057,497 $ 171,920 $ — $ 11,229,417 Total assets 15,288,142 200,778 25,529 15,514,449 Total deposits 12,371,522 6,169 — 12,377,691 Average assets 14,097,954 177,995 25,003 14,300,952

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Off-balance sheet commitments The Company is a party to credit related financial instruments with risk not reflected in the consolidated financial statements in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit, standby letters of credit, and commercial letters of credit. Such commitments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheets. The credit policies used for these commitments are consistent with those used for on-balance sheet instruments. The Company’s exposure to credit loss in the event of non-performance by its customers under such commitments or letters of credit represents the contractual amount of the financial instruments as indicated in the table below. At September 30, 2015 , and December 31, 2014 , the fair value of guarantees under commercial and standby letters of credit was $1.5 million and $1.3 million , respectively. This fair value amount represents the unamortized fee associated with these guarantees and is included in “Other liabilities” on the Company's consolidated balance sheets. This fair value will decrease as the existing commercial and standby letters of credit approach their expiration dates. The Company had the following financial instruments outstanding, whose contract amounts represent credit risk: (Dollars in thousands) September 30, 2015 December 31, 2014 Commitments to grant loans $ 140,139 $ 161,350 Unfunded commitments under lines of credit 4,602,464 4,007,954 Commercial and standby letters of credit 147,208 134,882 Reserve for unfunded lending commitments 14,525 11,801 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the commitments are expected to be drawn upon, the total commitment amounts generally represent future cash requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral, if any, is based on management’s credit evaluation of the customer. Unfunded commitments under commercial lines of credit, revolving credit lines and overdraft protection agreements are commitments for possible future extensions of credit to existing customers. Many of these types of commitments do not contain a specified maturity date and may or may not be drawn upon to the total extent to which the Company is committed. See Note 6 for additional discussion related to the Company’s unfunded lending commitments. Commercial and standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. These letters of credit are primarily issued to support public and private borrowing arrangements, including commercial paper issuance, bond financing, and similar transactions. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers and as such, are collateralized when necessary, generally in the form of marketable securities and cash equivalents. Legal proceedings The nature of the business of the Company’s banking and other subsidiaries ordinarily results in a certain amount of claims, litigation, investigations and legal and administrative cases and proceedings, all of which are considered incidental to the normal conduct of business. Some of these claims are against entities or assets of which the Company is a successor or acquired in business acquisitions, and certain of these claims will be covered by loss sharing agreements with the FDIC. The Company has asserted defenses to these litigations and, with respect to such legal proceedings, intends to continue to defend itself vigorously, litigating or settling cases according to management’s judgment as to what is in the best interest of the Company and its shareholders. The Company assesses its liabilities and contingencies in connection with outstanding legal proceedings utilizing the latest information available. Where it is probable that the Company will incur a loss and the amount of the loss can be reasonably estimated, the Company records a liability in its consolidated financial statements. These legal reserves may be increased or decreased to reflect any relevant developments on a quarterly basis. Where a loss is not probable or the amount of loss is not estimable, the Company does not accrue legal reserves. While the outcome of legal proceedings is inherently uncertain, based on information currently available, advice of counsel and available insurance coverage, the Company’s management believes that it has established appropriate legal reserves. Any liabilities arising from pending legal proceedings are not expected to have a material adverse effect on the Company’s consolidated financial position, consolidated results of operations or consolidated cash flows. However, in the event of unexpected future developments, it is possible that the ultimate resolution of these matters, if unfavorable, may be material to the Company’s consolidated financial position, consolidated results of operations or consolidated cash flows. As of the date of this filing, the Company believes the amount of losses associated with legal proceedings that it is reasonably possible to incur above amounts already accrued is immaterial.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
General	General The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information or footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments, consisting of normal and recurring items, necessary for a fair presentation of the consolidated financial statements have been made. These interim financial statements should be read in conjunction with the audited consolidated financial statements and footnote disclosures for IBERIABANK Corporation (the “Company”) previously filed with the Securities and Exchange Commission (the “SEC”) in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. Operating results for the three and nine month periods ended September 30, 2015 are not necessarily indicative of the results that may be expected for the year ended December 31, 2015. The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, IBERIABANK, Lenders Title Company (“LTC”), IBERIA Capital Partners, LLC (“ICP”), 1887 Leasing, LLC, IBERIA Asset Management, Inc. (“IAM”), and IBERIA CDE, LLC (“CDE”). All significant intercompany balances and transactions have been eliminated in consolidation. The Company offers commercial and retail banking products and services to customers throughout locations in seven states through IBERIABANK. The Company also operates mortgage production offices in 10 states through IBERIABANK Mortgage Company (“IMC”), a subsidiary of IBERIABANK, and offers a full line of title insurance and closing services throughout Arkansas and Louisiana through LTC and its subsidiaries. ICP provides equity research, institutional sales and trading, and corporate finance services. 1887 Leasing, LLC owns an aircraft used by management of the Company. IAM provides wealth management and trust services for commercial and private banking clients. CDE is engaged in the purchase of tax credits.
Reclassifications	Reclassifications Certain amounts reported in prior periods have been reclassified to conform to the current period presentation. These reclassifications did not have a material effect on previously reported consolidated net income, shareholders’ equity or cash flows.
Louisiana Business Corporation Act	Louisiana Business Corporation Act Effective January 1, 2015, companies incorporated under Louisiana law became subject to the Louisiana Business Corporation Act (which replaced the Louisiana Business Corporation Law). Provisions of the Louisiana Business Corporation Act eliminate the concept of treasury stock and provide that shares reacquired by a company are to be treated as authorized but unissued shares. As a result of this change in law, shares previously classified as treasury stock are presented as a reduction to issued shares of common stock in the consolidated financial statements as of September 30, 2015 , reducing the stated value of common stock and additional paid-in capital.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Material estimates that are susceptible to significant change in the near term are the allowance for credit losses, accounting for loans covered by loss sharing arrangements with the FDIC and the related loss share receivables, and determination of the fair value of net assets acquired in acquisitions.
Concentration of Credit Risks	Concentrations of Credit Risk Most of the Company’s business activity is with customers located within the states of Louisiana, Florida, Arkansas, Alabama, Texas, Tennessee and Georgia. The Company’s lending activity is concentrated in its market areas in those states. The Company has emphasized originations of commercial loans and private banking loans, defined as loans to larger consumer clients. Repayments on loans are expected to come from cash flows of the borrower and/or guarantor. Losses on secured loans are limited by the value of the collateral upon default of the borrowers. The Company does not have any significant concentrations to any one industry or customer.
Recent Accounting Pronouncements	ASU No. 2014-01 In January 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-01, “ Investments – Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects (a consensus of the FASB Emerging Issues Task Force)”. The ASU allows for use of the proportional amortization method for investments in qualified affordable housing projects if certain conditions are met. Under the proportional amortization method, the initial cost of the investment is amortized in proportion to the tax credits and other tax benefits received and the net investment performance is recognized in the consolidated statements of comprehensive income as a component of income tax expense. ASU 2014-01 provides for a practical expedient, which allows for amortization of the investment in proportion to only the tax credits if it produces a measurement that is substantially similar to the measurement that would result from using both tax credits and other tax benefits. ASU 2014-01 was effective for fiscal years and interim periods beginning after December 15, 2014. The Company adopted this guidance effective January 1, 2015, utilizing the practical expedient method. Amortization expense related to qualified affordable housing investments has been presented net of the income tax credits in income tax expense in the unaudited consolidated statements of comprehensive income. The standard was required to be applied retrospectively, therefore, prior periods have been restated in accordance with GAAP. The impact of the adoption of ASU 2014-01 was not material to the consolidated financial statements in current or prior periods. ASU No. 2015-02 In February 2015, the FASB issued ASU No. 2015-02, Consolidation: Amendments to the Consolidation Analysis , which changes the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The amendments in the guidance: 1) modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities (VIEs) or voting interest entities, 2) eliminate the presumption that a general partner should consolidate a limited partnership, 3) affect the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships, and 4) provide a scope exception from consolidation guidance for certain investment funds. ASU No. 2015-02 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The guidance may be applied using a modified retrospective approach by recording a cumulative effect adjustment to equity as of the beginning of the fiscal year of adoption. The amendments may also be applied retrospectively. The Company is still evaluating this ASU but does not expect that adoption will have a significant impact on the Company’s consolidated financial statements. ASU No. 2015-16 In September 2015, the FASB issued ASU No. 2015-16, Business Combinations: Simplifying the Accounting for Measurement-Period Adjustments. ASU No. 2015-16 requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined and present separately on the face of the income statement or disclose in the notes the portion of the amount recorded in current-period earnings by line item that would have been have been recorded in previous reporting periods if the adjustment had been recognized as of the acquisition date. ASU No. 2015-16 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The guidance must be applied prospectively to adjustments to provisional amounts that occur after the effective date of this update with earlier application permitted for financial statements that have not been issued. The Company adopted this guidance effective September 30, 2015. The adoption of this ASU did not have a significant impact on the Company’s consolidated financial statements.

Acquisition Activity (Tables)

Acquisition Activity (Tables)	9 Months Ended
	Sep. 30, 2015
Business Acquisition
Supplemental Pro Forma Information	The following unaudited pro forma information for the nine months ended September 30, 2014 reflects the Company’s estimated consolidated results of operations as if the acquisitions of Florida Bank Group, Old Florida, and Georgia Commerce occurred at January 1, 2014, unadjusted for potential cost savings and/or synergies and preliminary purchase price adjustments. For the Nine Months Ended (Dollars in thousands, except per share data) September 30, 2014 Interest and non-interest income $ 586,979 Net income 88,615 Earnings per share - basic 2.28 Earnings per share - diluted 2.28
Florida Bank Group, Inc.
Business Acquisition
Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable	The following summarizes consideration paid and a preliminary allocation of purchase price to net assets acquired. (Dollars in thousands) Number of Shares Amount Equity consideration Common stock issued 752,493 $ 47,497 Total equity consideration 47,497 Non-Equity consideration Cash 42,988 Total consideration paid 90,485 Fair value of net assets assumed including identifiable intangible assets 73,736 Goodwill $ 16,749
Schedule of Business Acquisitions, by Acquisition	The acquired assets and liabilities, as well as the preliminary adjustments to record the assets and liabilities at their estimated fair values, are presented in the following tables. Florida Bank Group (Dollars in thousands) As Acquired Preliminary Fair Value Adjustments As recorded by the Company Assets Cash and cash equivalents $ 72,982 $ — $ 72,982 Investment securities 107,236 136 (1) 107,372 Loans 312,902 (7,073 ) (2) 305,829 Other real estate owned 498 (75 ) (3) 423 Core deposit intangible — 4,489 (4) 4,489 Deferred tax asset, net 19,889 9,232 (5) 29,121 Other assets 29,810 (8,949 ) (6) 20,861 Total Assets $ 543,317 $ (2,240 ) $ 541,077 Liabilities Interest-bearing deposits $ 282,417 $ 263 (7) $ 282,680 Non-interest-bearing deposits 109,548 — 109,548 Borrowings 60,000 8,598 (8) 68,598 Other liabilities 1,897 4,618 (9) 6,515 Total Liabilities $ 453,862 $ 13,479 $ 467,341 Explanation of certain fair value adjustments: (1) The amount represents the adjustment of the book value of Florida Bank Group’s investments to their estimated fair value on the date of acquisition. (2) The amount represents the adjustment of the book value of Florida Bank Group's loans to their estimated fair value based on current interest rates and expected cash flows, which includes estimates of expected credit losses inherent in the portfolio. (3) The adjustment represents the adjustment of Florida Bank Group's OREO to its estimated fair value on the date of acquisition. (4) The amount represents the fair value of the core deposit intangible asset created in the acquisition. (5) The amount represents the deferred tax asset recognized on the fair value adjustment of Florida Bank Group acquired assets and assumed liabilities. (6) The amount represents the adjustment of the book value of Florida Bank Group’s property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value. (7) The adjustment is necessary because the weighted average interest rate of Florida Bank Group’s deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio, which is estimated at 51 months . (8) The amount represents the adjustment of the book value of Florida Bank Group’s borrowings to their estimated fair value based on current interest rates and the credit characteristics inherent in the liability. (9) The amount is necessary to record Florida Bank Group's rent liability at fair value.
Old Florida Bancshares, Inc.
Business Acquisition
Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable	The following summarizes consideration paid and a preliminary allocation of purchase price to net assets acquired. (Dollars in thousands) Number of Shares Amount Equity consideration Common stock issued 3,839,554 $ 242,007 Total equity consideration 242,007 Non-Equity consideration Cash 11,145 Total consideration paid 253,152 Fair value of net assets assumed including identifiable intangible assets 153,621 Goodwill $ 99,531
Schedule of Business Acquisitions, by Acquisition	Old Florida (Dollars in thousands) As Acquired Preliminary Fair Value Adjustments As recorded by the Company Assets Cash and cash equivalents $ 360,688 $ — $ 360,688 Investment securities 67,209 — 67,209 Loans held for sale 5,952 — 5,952 Loans 1,073,773 (9,342 ) (1) 1,064,431 Other real estate owned 4,515 (2 ) (2) 4,513 Core deposit intangible — 10,055 (3) 10,055 Deferred tax asset, net 8,470 3,181 (4) 11,651 Other assets 30,732 (7,238 ) (5) 23,494 Total Assets $ 1,551,339 $ (3,346 ) $ 1,547,993 Liabilities Interest-bearing deposits $ 1,048,765 $ 123 (6) $ 1,048,888 Non-interest-bearing deposits 340,869 — 340,869 Borrowings 1,528 — 1,528 Other liabilities 3,011 76 (7) 3,087 Total Liabilities $ 1,394,173 $ 199 $ 1,394,372 Explanation of certain fair value adjustments: (1) The amount represents the adjustment of the book value of Old Florida's loans to their estimated fair value based on current interest rates and expected cash flows, which includes estimates of expected credit losses inherent in the portfolio. (2) The adjustment represents the adjustment of Old Florida's OREO to its estimated fair value on the date of acquisition. (3) The amount represents the fair value of the core deposit intangible asset created in the acquisition. (4) The amount represents the net deferred tax asset recognized on the fair value adjustment of Old Florida acquired assets and assumed liabilities. (5) The amount represents the adjustment of the book value of Old Florida’s property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value. (6) The adjustment is necessary because the weighted average interest rate of Old Florida’s deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio, which is estimated at 56 months . (7) The adjustment is necessary to record Old Florida's rent liability at fair value.
Georgia Commerce Bancshares, Inc.
Business Acquisition
Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable	The following summarizes consideration paid and a preliminary allocation of purchase price to net assets acquired. (Dollars in thousands) Number of Shares Amount Equity consideration Common stock issued 2,882,357 $ 185,249 Total equity consideration 185,249 Non-Equity consideration Cash 5,015 Total consideration paid 190,264 Fair value of net assets assumed including identifiable intangible assets 109,024 Goodwill $ 81,240
Schedule of Business Acquisitions, by Acquisition	Georgia Commerce (Dollars in thousands) As Acquired Preliminary As recorded by Assets Cash and cash equivalents $ 51,059 $ — $ 51,059 Investment securities 139,035 (806 ) (1) 138,229 Loans held for sale 1,249 — 1,249 Loans 807,726 (6,622 ) (2) 801,104 Other real estate owned 9,795 (4,182 ) (3) 5,613 Core deposit intangible — 7,448 (4) 7,448 Deferred tax asset, net 5,030 1,849 (5) 6,879 Other assets 30,587 (657 ) (6) 29,930 Total Assets $ 1,044,481 $ (2,970 ) $ 1,041,511 Liabilities Interest-bearing deposits 658,133 176 (7) 658,309 Non-interest-bearing deposits 249,739 — 249,739 Borrowings 13,203 — 13,203 Other liabilities 11,236 — 11,236 Total Liabilities $ 932,311 $ 176 $ 932,487 Explanation of certain fair value adjustments: (1) The amount represents the adjustment of the book value of Georgia Commerce’s investments to their estimated fair value on the date of acquisition. (2) The amount represents the adjustment of the book value of Georgia Commerce's loans to their estimated fair value based on current interest rates and expected cash flows, which includes estimates of expected credit losses inherent in the portfolio. (3) The adjustment represents the adjustment of Georgia Commerce's OREO to its estimated fair value on the date of acquisition. (4) The amount represents the fair value of the core deposit intangible asset created in the acquisition. (5) The amount represents the net deferred tax asset recognized on the fair value adjustment of Georgia Commerce acquired assets and assumed liabilities. (6) The amount represents the adjustment of the book value of Georgia Commerce’s property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value. (7) The adjustment is necessary because the weighted average interest rate of Georgia Commerce’s deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio, which is estimated at 60 months .

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities	The amortized cost and fair values of investment securities, with gross unrealized gains and losses, consist of the following: September 30, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 277,822 $ 2,743 $ (45 ) $ 280,520 Obligations of states and political subdivisions 181,626 4,502 — 186,128 Mortgage-backed securities 2,246,002 22,157 (3,647 ) 2,264,512 Other securities 96,301 694 (350 ) 96,645 Total securities available for sale $ 2,801,751 $ 30,096 $ (4,042 ) $ 2,827,805 Securities held to maturity: Obligations of states and political subdivisions $ 73,821 $ 2,878 $ (74 ) $ 76,625 Mortgage-backed securities 24,509 103 (626 ) 23,986 Total securities held to maturity $ 98,330 $ 2,981 $ (700 ) $ 100,611 December 31, 2014 Amortized Cost Gross Gross Estimated (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 317,386 $ 1,700 $ (3,533 ) $ 315,553 Obligations of states and political subdivisions 86,513 3,679 (2 ) 90,190 Mortgage-backed securities 1,741,917 16,882 (7,184 ) 1,751,615 Other securities 1,460 35 — 1,495 Total securities available for sale $ 2,147,276 $ 22,296 $ (10,719 ) $ 2,158,853 Securities held to maturity: U.S. Government-sponsored enterprise obligations $ 10,000 $ 88 $ — $ 10,088 Obligations of states and political subdivisions 77,597 3,153 (145 ) 80,605 Mortgage-backed securities 29,363 151 (726 ) 28,788 Total securities held to maturity $ 116,960 $ 3,392 $ (871 ) $ 119,481
Held-to-maturity Securities	The amortized cost and fair values of investment securities, with gross unrealized gains and losses, consist of the following: September 30, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 277,822 $ 2,743 $ (45 ) $ 280,520 Obligations of states and political subdivisions 181,626 4,502 — 186,128 Mortgage-backed securities 2,246,002 22,157 (3,647 ) 2,264,512 Other securities 96,301 694 (350 ) 96,645 Total securities available for sale $ 2,801,751 $ 30,096 $ (4,042 ) $ 2,827,805 Securities held to maturity: Obligations of states and political subdivisions $ 73,821 $ 2,878 $ (74 ) $ 76,625 Mortgage-backed securities 24,509 103 (626 ) 23,986 Total securities held to maturity $ 98,330 $ 2,981 $ (700 ) $ 100,611 December 31, 2014 Amortized Cost Gross Gross Estimated (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 317,386 $ 1,700 $ (3,533 ) $ 315,553 Obligations of states and political subdivisions 86,513 3,679 (2 ) 90,190 Mortgage-backed securities 1,741,917 16,882 (7,184 ) 1,751,615 Other securities 1,460 35 — 1,495 Total securities available for sale $ 2,147,276 $ 22,296 $ (10,719 ) $ 2,158,853 Securities held to maturity: U.S. Government-sponsored enterprise obligations $ 10,000 $ 88 $ — $ 10,088 Obligations of states and political subdivisions 77,597 3,153 (145 ) 80,605 Mortgage-backed securities 29,363 151 (726 ) 28,788 Total securities held to maturity $ 116,960 $ 3,392 $ (871 ) $ 119,481
Schedule of Securities with Gross Unrealized Losses Aggregated by Investment Category	Information pertaining to securities with gross unrealized losses, aggregated by investment category and length of time that individual securities have been in a continuous loss position, is as follows: September 30, 2015 Less Than Twelve Months Over Twelve Months Total Gross Unrealized Losses Estimated Fair Value Gross Estimated Gross Estimated (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ — $ — $ (45 ) $ 28,449 $ (45 ) $ 28,449 Mortgage-backed securities (954 ) 252,358 (2,693 ) 191,836 (3,647 ) 444,194 Other securities (346 ) 27,626 (4 ) 505 (350 ) 28,131 Total securities available for sale $ (1,300 ) $ 279,984 $ (2,742 ) $ 220,790 $ (4,042 ) $ 500,774 Securities held to maturity: Obligations of states and political subdivisions $ (6 ) $ 3,642 $ (68 ) $ 4,199 $ (74 ) $ 7,841 Mortgage-backed securities (17 ) 1,054 (609 ) 18,286 (626 ) 19,340 Total securities held to maturity $ (23 ) $ 4,696 $ (677 ) $ 22,485 $ (700 ) $ 27,181 December 31, 2014 Less Than Twelve Months Over Twelve Months Total Gross Estimated Gross Estimated Gross Estimated (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ — $ — $ (3,533 ) $ 240,498 $ (3,533 ) $ 240,498 Obligations of states and political subdivisions (2 ) 185 — — (2 ) 185 Mortgage-backed securities (1,189 ) 304,686 (5,995 ) 294,549 (7,184 ) 599,235 Total securities available for sale $ (1,191 ) $ 304,871 $ (9,528 ) $ 535,047 $ (10,719 ) $ 839,918 Securities held to maturity: Obligations of states and political subdivisions $ (9 ) $ 2,287 $ (136 ) $ 8,590 $ (145 ) $ 10,877 Mortgage-backed securities — — (726 ) 20,812 (726 ) 20,812 Total securities held to maturity $ (9 ) $ 2,287 $ (862 ) $ 29,402 $ (871 ) $ 31,689
Additional Information on Securities in a Continuous Loss Position	Additional information on securities that have been in a continuous loss position for over twelve months at September 30, 2015 and December 31, 2014 is presented in the following table. (Dollars in thousands) September 30, 2015 December 31, 2014 Number of securities Issued by Fannie Mae, Freddie Mac, or Ginnie Mae 39 66 Issued by political subdivisions 2 5 Other 1 — 42 71 Amortized cost basis Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 241,918 $ 566,113 Issued by political subdivisions 4,267 8,727 Other 509 — $ 246,694 $ 574,840 Unrealized loss Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 3,347 $ 10,254 Issued by political subdivisions 68 136 Other 4 — $ 3,419 $ 10,390
Schedule of Amortized Cost and Estimated Fair Value of Investment Securities by Maturity	The amortized cost and estimated fair value of investment securities by maturity at September 30, 2015 are shown in the following table. Securities are classified according to their contractual maturities without consideration of principal amortization, potential prepayments or call options. Accordingly, actual maturities may differ from contractual maturities. Weighted average yields are calculated on the basis of the yield to maturity based on the amortized cost of each security. Securities Available for Sale Securities Held to Maturity Weighted Average Yield Amortized Cost Estimated Fair Value Weighted Amortized Cost Estimated (Dollars in thousands) Within one year or less 1.63 % $ 25,724 $ 25,824 3.85 % $ 75 $ 75 One through five years 1.69 % 298,322 301,724 2.79 % 11,552 11,808 After five through ten years 2.23 % 516,467 524,969 3.09 % 20,663 21,494 Over ten years 2.12 % 1,961,238 1,975,288 2.98 % 66,040 67,234 2.09 % $ 2,801,751 $ 2,827,805 2.98 % $ 98,330 $ 100,611
Schedule of Realized Gains and Losses from Sale of Securities Classified as Available for Sale	The following is a summary of realized gains and losses from the sale of securities classified as available for sale. Gains or losses on securities sold are recorded on the trade date, using the specific identification method. Three Months Ended September 30, Nine Months Ended September 30, (Dollars in thousands) 2015 2014 2015 2014 Realized gains $ 425 $ 582 $ 1,786 $ 609 Realized losses (145 ) — (217 ) — $ 280 $ 582 $ 1,569 $ 609
Schedule of Securities in Other Assets on Company's Consolidated Balance Sheets	The Company included the following securities, accounted for at amortized cost, which approximates fair value, in “Other assets” on the consolidated balance sheets: (Dollars in thousands) September 30, 2015 December 31, 2014 Federal Home Loan Bank (FHLB) stock $ 14,603 $ 38,476 Federal Reserve Bank (FRB) stock 48,584 34,348 Other investments 1,158 1,306 $ 64,345 $ 74,130

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2015
Receivables [Abstract]
Schedule of Non-Covered and Covered Loans	Loans consist of the following, segregated into non-covered and covered loans, for the periods indicated: September 30, 2015 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans Total Commercial loans: Real estate $ 4,321,723 $ 1,614,438 $ 43,590 $ 5,979,751 Commercial and industrial 2,779,503 512,049 11,419 3,302,971 Energy-related 713,935 5,521 — 719,456 7,815,161 2,132,008 55,009 10,002,178 Residential mortgage loans: Residential 1-4 family 596,428 398,398 119,926 1,114,752 Construction / Owner Occupied 64,115 11,074 — 75,189 660,543 409,472 119,926 1,189,941 Consumer and other loans: Home equity 1,488,796 449,665 77,226 2,015,687 Indirect automobile 281,522 127 — 281,649 Other 533,236 92,948 1,380 627,564 2,303,554 542,740 78,606 2,924,900 Total $ 10,779,258 $ 3,084,220 $ 253,541 $ 14,117,019 December 31, 2014 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans (1) Total Commercial loans: Real estate $ 3,676,811 $ 495,842 $ 189,126 $ 4,361,779 Commercial and industrial 2,452,521 87,914 31,260 2,571,695 Energy-related 872,866 7,742 — 880,608 7,002,198 591,498 220,386 7,814,082 Residential mortgage loans: Residential 1-4 family 495,638 424,579 128,024 1,048,241 Construction / Owner Occupied 32,056 — — 32,056 527,694 424,579 128,024 1,080,297 Consumer and other loans: Home equity 1,290,976 217,699 92,430 1,601,105 Indirect automobile 396,766 392 — 397,158 Other 451,080 93,618 3,704 548,402 2,138,822 311,709 96,134 2,546,665 Total $ 9,668,714 $ 1,327,786 $ 444,544 $ 11,441,044 (1) Included as covered loans at December 31, 2014 is $174.7 million of assets whose reimbursable loss periods ended as of January 1, 2015.
Schedule of Aging of Non-Covered Loans	The following tables provide an analysis of the aging of non-covered loans as of September 30, 2015 and December 31, 2014 . Due to the difference in accounting for acquired loans, the tables below further segregate the Company’s non-covered loans between loans originated by the Company (“legacy loans”) and acquired loans. September 30, 2015 Legacy loans Total Legacy Loans, Net of Unearned Income Recorded Investment > 90 days and Accruing Past Due (1) (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ — $ — $ 180 $ 180 $ 559,028 $ 559,208 $ — Commercial real estate - Other 1,225 1,763 14,541 17,529 3,744,986 3,762,515 242 Commercial and industrial 1,087 672 11,139 12,898 2,766,605 2,779,503 363 Energy-related — — 3,478 3,478 710,457 713,935 — Residential mortgage 1,832 2,054 15,730 19,616 640,927 660,543 851 Consumer - Home equity 2,232 853 5,343 8,428 1,480,368 1,488,796 65 Consumer - Indirect automobile 1,927 470 1,129 3,526 277,996 281,522 — Consumer - Credit card 247 116 335 698 76,018 76,716 — Consumer - Other 900 339 920 2,159 454,361 456,520 — Total $ 9,450 $ 6,267 $ 52,795 $ 68,512 $ 10,710,746 $ 10,779,258 $ 1,521 December 31, 2014 Legacy loans Total Legacy Recorded Investment > 90 days and Accruing Past Due (1) (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ 507 $ — $ 69 $ 576 $ 483,663 $ 484,239 $ — Commercial real estate - Other 11,799 148 6,859 18,806 3,173,766 3,192,572 — Commercial and industrial 1,589 1,860 3,225 6,674 2,445,847 2,452,521 200 Energy-related — — 27 27 872,839 872,866 — Residential mortgage 1,389 2,616 14,900 18,905 508,789 527,694 538 Consumer - Home equity 4,096 595 7,420 12,111 1,278,865 1,290,976 16 Consumer - Indirect automobile 2,447 396 1,419 4,262 392,504 396,766 — Consumer - Credit card 253 163 1,032 1,448 71,297 72,745 — Consumer - Other 1,285 424 773 2,482 375,853 378,335 — Total $ 23,365 $ 6,202 $ 35,724 $ 65,291 $ 9,603,423 $ 9,668,714 $ 754 (1) Past due loans greater than 90 days days include all loans on non-accrual status, regardless of past due status, as of the period indicated. Non-accrual loans are presented separately in the “Non-accrual Loans” section below. September 30, 2015 Non-covered acquired loans Past Due (1) Discount/Premium Total Non-covered Acquired Loans, Net of Unearned Income Recorded Investment > 90 days and Accruing (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ — $ 260 $ 6,965 $ 7,225 $ 118,084 $ (1,548 ) $ 123,761 $ 6,965 Commercial real estate - Other 3,267 25 40,206 43,498 1,487,123 (39,944 ) 1,490,677 39,066 Commercial and industrial 1,464 346 6,566 8,376 508,047 (4,374 ) 512,049 5,882 Energy-related 95 382 1,392 1,869 3,652 — 5,521 1,392 Residential mortgage 85 846 5,470 6,401 407,673 (4,602 ) 409,472 4,430 Consumer - Home equity 1,063 221 6,097 7,381 452,928 (10,644 ) 449,665 5,643 Consumer - Indirect automobile — 5 19 24 142 (39 ) 127 19 Consumer - Other 593 116 646 1,355 95,353 (3,760 ) 92,948 575 Total $ 6,567 $ 2,201 $ 67,361 $ 76,129 $ 3,073,002 $ (64,911 ) $ 3,084,220 $ 63,972 December 31, 2014 Non-covered acquired loans Past Due (1) Discount/Premium Total Non-covered Acquired Loans, Net of Unearned Income Recorded Investment > 90 days and Accruing (Dollars in thousands) 30-59 days 60-89 days > 90 days Total Current Commercial real estate - Construction $ 2,740 $ 57 $ 1,284 $ 4,081 $ 26,667 $ (1,170 ) $ 29,578 $ 1,284 Commercial real estate - Other 4,419 840 26,480 31,739 473,644 (39,119 ) 466,264 26,376 Commercial and industrial 2,106 70 1,624 3,800 89,338 (5,224 ) 87,914 1,635 Energy-related — — 11 11 7,731 — 7,742 — Residential mortgage 152 2,367 9,339 11,858 418,552 (5,831 ) 424,579 8,087 Consumer - Home equity 649 385 8,774 9,808 216,310 (8,419 ) 217,699 8,383 Consumer - Indirect automobile 13 17 9 39 393 (40 ) 392 9 Consumer - Other 1,458 113 1,949 3,520 94,315 (4,217 ) 93,618 1,829 Total $ 11,537 $ 3,849 $ 49,470 $ 64,856 $ 1,326,950 $ (64,020 ) $ 1,327,786 $ 47,603 (1) Past due information presents acquired loans at the gross loan balance, prior to application of discounts.
Schedule of Legacy Loans on Nonaccrual Status	The following table provides the recorded investment of legacy loans on non-accrual status at the periods indicated. (Dollars in thousands) September 30, 2015 December 31, 2014 Commercial real estate - Construction $ 180 $ 69 Commercial real estate - Other 14,299 6,859 Commercial and industrial 10,776 3,025 Energy-related 3,478 27 Residential mortgage 14,879 14,362 Consumer - Home equity 5,278 7,404 Consumer - Indirect automobile 1,129 1,419 Consumer - Credit card 335 1,032 Consumer - Other 920 773 Total $ 51,274 $ 34,970
Schedule of Carrying Amount of Acquired Covered Loans	The carrying amount of the acquired covered loans at September 30, 2015 and December 31, 2014 consisted of loans determined to be impaired at the acquisition date, which are accounted for in accordance with ASC Topic 310-30, Receivables – Loans and Debt Securities Acquired with Deteriorated Credit Quality , and loans that were considered to be performing at the acquisition date, accounted for by analogy to ASC Topic 310-30, as detailed in the following tables. September 30, 2015 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Loans Total Covered Loans Commercial loans: Real estate $ 18,576 $ 25,014 $ 43,590 Commercial and industrial 567 10,852 11,419 19,143 35,866 55,009 Residential mortgage loans: Residential 1-4 family 25,100 94,826 119,926 25,100 94,826 119,926 Consumer and other loans: Home equity 8,038 69,188 77,226 Other 20 1,360 1,380 8,058 70,548 78,606 Total $ 52,301 $ 201,240 $ 253,541 December 31, 2014 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Loans Total Covered Loans Commercial loans: Real estate $ 1,253 $ 187,873 $ 189,126 Commercial and industrial — 31,260 31,260 1,253 219,133 220,386 Residential mortgage loans: Residential 1-4 family 22,918 105,106 128,024 22,918 105,106 128,024 Consumer and other loans: Home equity 12,872 79,558 92,430 Other 489 3,215 3,704 13,361 82,773 96,134 Total $ 37,532 $ 407,012 $ 444,544
Schedule of Carrying Amount of Loan Acquired	The tables below show the balances acquired during the first nine months of 2015 for these two subsections of the portfolio as of the acquisition date. These amounts are subject to change due to the finalization of purchase accounting adjustments. (Dollars in thousands) Contractually required principal and interest at acquisition $ 2,402,890 Expected losses and foregone interest (18,979 ) Cash flows expected to be collected at acquisition 2,383,911 Fair value of acquired loans at acquisition $ 2,130,276 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Impaired Loans Total Acquired Loans Contractually required principal and interest at acquisition $ 53,532 $ — $ 53,532 Non-accretable difference (expected losses and foregone interest) (7,852 ) — (7,852 ) Cash flows expected to be collected at acquisition 45,680 — 45,680 Accretable yield (4,592 ) — (4,592 ) Basis in acquired loans at acquisition $ 41,088 $ — $ 41,088
Summary of Changes in Accretable Yields of Acquired Loans	The following is a summary of changes in the accretable difference for loans accounted for under ASC 310-30 during the nine months ended September 30: 2015 (Dollars in thousands) Acquired Impaired Loans Acquired Performing Impaired Loans Total Acquired Loans Balance at beginning of period $ 74,249 $ 213,402 $ 287,651 Acquisition 4,592 — 4,592 Transfers from non-accretable difference to accretable yield 70 7,129 7,199 Accretion (9,774 ) (50,531 ) (60,305 ) Changes in expected cash flows not affecting non-accretable differences (1) 1,209 (2,720 ) (1,511 ) Balance at end of period $ 70,346 $ 167,280 $ 237,626 2014 Acquired Impaired Loans Acquired Performing Impaired Loans Total Acquired Loans Balance at beginning of period $ 78,349 $ 276,543 $ 354,892 Acquisition 8,242 1,536 9,778 Transfers from non-accretable difference to accretable yield 3,952 13,872 17,824 Accretion (12,766 ) (66,590 ) (79,356 ) Changes in expected cash flows not affecting non-accretable differences (1) (6,873 ) (19,377 ) (26,250 ) Balance at end of period $ 70,904 $ 205,984 $ 276,888
Schedule of Modified TDRs	The following table provides information on how the TDRs were modified during the nine months ended September 30, 2015 : (Dollars in thousands) 2015 Extended maturities $ 15,932 Maturity and interest rate adjustment 23,552 Forbearance 1,228 Other concession(s) (1) 7,887 Total $ 48,599 (1) Other concessions include concessions or a combination of concessions that do not consist of maturity extensions, interest rate adjustments, forbearance or covenant modifications.
Schedule of Subsequently Defaulted TDRs	The following table presents the end of period balance for loans modified in a TDR during the nine-month period ended September 30, 2015 and the financial impact of those modifications. September 30, 2015 (In thousands, except number of loans) Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment (1) Commercial real estate 8 $ 26,408 $ 25,572 Commercial and industrial 18 19,798 19,643 Energy-related 1 3,434 3,384 Total 27 $ 49,640 $ 48,599 (1) Recorded investment includes any allowance for credit losses recorded on the TDRs at the dates indicated. Information detailing TDRs which defaulted during the nine months ended September 30, 2015 and 2014 , and which were modified in the previous twelve months (i.e., the twelve months prior to the default) is presented in the following table. The Company has defined a default as any loan with a loan payment that is currently past due greater than 30 days , or was past due greater than 30 days at any point during the previous twelve months, or since the date of modification, whichever is shorter. September 30, 2015 September 30, 2014 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate 4 $ 12,939 31 $ 58 Commercial and industrial 15 13,145 11 1,767 Energy-related 1 3,384 — — Consumer - Home Equity — — — — Consumer - Other — — 1 — Total 20 $ 29,468 43 $ 1,825

Allowance for Credit Losses a29

Allowance for Credit Losses and Credit Quality (Tables)	9 Months Ended
	Sep. 30, 2015
Receivables [Abstract]
Schedule of Allowance for Loan Losses for Covered Loan and Non-Covered Loan Portfolios	A summary of changes in the allowance for credit losses for the covered loan and non-covered loan portfolios for the nine months ended September 30, is as follows: 2015 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans Total Allowance for loans losses at beginning of period $ 76,174 $ 9,193 $ 44,764 $ 130,131 Provision for loan losses before benefit attributable to FDIC loss share agreements 17,743 143 (31 ) 17,855 Adjustment attributable to FDIC loss share arrangements — — 1,342 1,342 Net provision for loan losses 17,743 143 1,311 19,197 Adjustment attributable to FDIC loss share arrangements — — (1,342 ) (1,342 ) Transfer of balance to OREO — (209 ) (357 ) (566 ) Transfer of balance to non-covered — 28,700 (28,700 ) — Loans charged-off (12,073 ) (8,973 ) (1,188 ) (22,234 ) Recoveries 4,556 504 8 5,068 Allowance for loans losses at end of period 86,400 29,358 14,496 130,254 Reserve for unfunded commitments at beginning of period 11,801 — — 11,801 Provision for unfunded lending commitments 2,724 — — 2,724 Reserve for unfunded commitments at end of period 14,525 — — 14,525 Allowance for credit losses at end of period $ 100,925 $ 29,358 $ 14,496 $ 144,779 2014 Non-covered loans (Dollars in thousands) Legacy Loans Acquired Loans Covered Loans Total Allowance for loans losses at beginning of period $ 67,342 $ 4,557 $ 71,175 $ 143,074 Provision for (Reversal of) loan losses before benefit attributable to FDIC loss share agreements 9,635 (1,795 ) 5,878 13,718 Adjustment attributable to FDIC loss share arrangements — — (1,153 ) (1,153 ) Net provision for (reversal of) loan losses 9,635 (1,795 ) 4,725 12,565 Adjustment attributable to FDIC loss share arrangements — — 1,153 1,153 Transfer of balance to OREO — (207 ) (5,171 ) (5,378 ) Loans charged-off (8,242 ) (586 ) (12,823 ) (21,651 ) Recoveries 4,338 401 38 4,777 Allowance for loans losses at end of period 73,073 2,370 59,097 134,540 Reserve for unfunded commitments at beginning of period 11,147 — — 11,147 Provision for unfunded lending commitments 952 — — 952 Reserve for unfunded commitments at end of period 12,099 — — 12,099 Allowance for credit losses at end of period $ 85,172 $ 2,370 $ 59,097 $ 146,639 A summary of changes in the allowance for credit losses for non-covered loans, by loan portfolio type, for the nine months ended September 30, is as follows: 2015 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 32,630 $ 26,486 $ 5,999 $ 2,875 $ 17,377 $ 85,367 (Reversal of) Provision for loan losses (356 ) 1,327 9,339 1,897 5,679 17,886 Transfer of balance to OREO 174 (169 ) — (143 ) (71 ) (209 ) Transfer of balance to non-covered 20,763 1,445 — — 6,492 28,700 Loans charged off (7,091 ) (1,162 ) (3 ) (283 ) (12,507 ) (21,046 ) Recoveries 1,543 164 — 48 3,305 5,060 Allowance for loans losses at end of period 47,663 28,091 15,335 4,394 20,275 115,758 Reserve for unfunded commitments Balance at beginning of period 3,370 3,733 1,596 168 2,934 11,801 (Reversal of) Provision for unfunded commitments 218 (149 ) 2,037 650 (32 ) 2,724 Balance at end of period 3,588 3,584 3,633 818 2,902 14,525 Allowance for credit losses at end of period $ 51,251 $ 31,675 $ 18,968 $ 5,212 $ 23,177 $ 130,283 Allowance on loans individually evaluated for impairment $ 883 $ 817 $ — $ — $ 16 $ 1,716 Allowance on loans collectively evaluated for impairment 50,368 30,858 18,968 5,212 23,161 128,567 Loans, net of unearned income: Balance at end of period $ 5,936,161 $ 3,291,552 $ 719,456 $ 1,070,015 $ 2,846,294 $ 13,863,478 Balance at end of period individually evaluated for impairment 27,299 25,231 — — 214 52,744 Balance at end of period collectively evaluated for impairment 5,874,262 3,255,580 719,456 1,056,797 2,838,500 13,744,595 Balance at end of period acquired with deteriorated credit quality 34,600 10,741 — 13,218 7,580 66,139 2014 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 26,126 $ 22,101 $ 6,878 $ 2,546 $ 14,248 $ 71,899 Provision for (Reversal of) loan losses 630 3,283 (1,115 ) 514 4,528 7,840 Transfer of balance to OREO — (130 ) — (12 ) (65 ) (207 ) Loans charged off (1,214 ) (1,097 ) — (607 ) (5,910 ) (8,828 ) Recoveries 2,209 93 — 134 2,303 4,739 Allowance for loans losses at end of period 27,751 24,250 5,763 2,575 15,104 75,443 Reserve for unfunded commitments at beginning of period 3,071 1,814 3,043 72 3,147 11,147 Provision for unfunded commitments 671 1,674 (1,427 ) 11 23 952 Reserve for unfunded commitments at end of period 3,742 3,488 1,616 83 3,170 12,099 Allowance for credit losses at end of period $ 31,493 $ 27,738 $ 7,379 $ 2,658 $ 18,274 $ 87,542 Allowance on loans individually evaluated for impairment $ 25 $ — $ — $ — $ — $ 25 Allowance on loans collectively evaluated for impairment 31,468 27,738 7,379 2,658 18,274 87,517 Loans, net of unearned income: Balance at end of period $ 3,988,172 $ 2,398,010 $ 839,823 $ 931,803 $ 2,398,890 $ 10,556,698 Balance at end of period individually evaluated for impairment 7,357 3,276 — — 706 11,339 Balance at end of period collectively evaluated for impairment 3,965,754 2,392,172 839,823 931,643 2,396,477 10,525,869 Balance at end of period acquired with deteriorated credit quality 15,061 2,562 — 160 1,707 19,490 A summary of changes in the allowance for credit losses for covered loans, by loan portfolio type, for the nine months ended September 30, is as follows: 2015 Commercial Real Estate Commercial and Industrial Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 24,072 $ 1,235 $ 6,286 $ 13,171 $ 44,764 Provision for loan losses 217 152 841 101 1,311 (Decrease) Increase in FDIC loss share receivable 748 59 (277 ) (1,872 ) (1,342 ) Transfer of balance to OREO — (1 ) (339 ) (17 ) (357 ) Transfer of balance to non-covered (20,763 ) (1,445 ) — (6,492 ) (28,700 ) Loans charged off (1,188 ) — — — (1,188 ) Recoveries — — 8 — 8 Allowance for loans losses at end of period $ 3,086 $ — $ 6,519 $ 4,891 $ 14,496 Allowance on loans individually evaluated for impairment $ — $ — $ — $ — $ — Allowance on loans collectively evaluated for impairment 3,086 — 6,519 4,891 14,496 Loans, net of unearned income: Balance at end of period $ 43,590 $ 11,419 $ 119,926 $ 78,606 $ 253,541 Balance at end of period individually evaluated for impairment — — — — — Balance at end of period collectively evaluated for impairment 25,014 10,852 94,826 70,548 201,240 Balance at end of period acquired with deteriorated credit quality 18,576 567 25,100 8,058 52,301 2014 Commercial Real Estate Commercial and Industrial Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 38,772 $ 5,380 $ 10,889 $ 16,134 $ 71,175 Provision for loan losses 2,544 376 971 834 4,725 (Decrease) Increase in FDIC loss share receivable 734 609 (2,911 ) 2,721 1,153 Transfer of balance to OREO (1,874 ) (1,162 ) (648 ) (1,487 ) (5,171 ) Loans charged off (9,578 ) (2,192 ) (90 ) (963 ) (12,823 ) Recoveries 38 — — — 38 Allowance for loans losses at end of period $ 30,636 $ 3,011 $ 8,211 $ 17,239 $ 59,097 Allowance on loans individually evaluated for impairment $ — $ — $ — $ — $ — Allowance on loans collectively evaluated for impairment 30,636 3,011 8,211 17,239 59,097 Loans, net of unearned income: Balance at end of period $ 247,156 $ 34,234 $ 130,976 $ 111,823 $ 524,189 Balance at end of period individually evaluated for impairment — — — — — Balance at end of period collectively evaluated for impairment 242,478 33,614 106,672 95,124 477,888 Balance at end of period acquired with deteriorated credit quality 4,678 620 24,304 16,699 46,301
Investment in Covered Loans and Non-Covered Loans by Credit Quality Indicator	The Company’s investment in non-covered loans by credit quality indicator is presented in the following tables. Because of the difference in accounting for acquired loans, the tables below further segregate the Company’s non-covered loans between acquired loans and loans that were not acquired. Loan premiums/discounts in the tables below represent the adjustment of non-covered acquired loans to fair value at the acquisition date, as adjusted for income accretion and changes in cash flow estimates in subsequent periods. Asset risk classifications for commercial loans reflect the classification as of September 30, 2015 and December 31, 2014 . Credit quality information in the tables below includes loans acquired at the gross loan balance, prior to the application of premiums/discounts, at September 30, 2015 and December 31, 2014 . Legacy loans September 30, 2015 December 31, 2014 (Dollars in thousands) Pass Special Mention Sub-standard Doubtful Loss Total Pass Special Mention Sub-standard Doubtful Total Commercial real estate - Construction $ 557,603 $ 100 $ 1,503 $ — $ 2 $ 559,208 $ 483,930 $ 240 $ 69 $ — $ 484,239 Commercial real estate - Other 3,699,714 24,473 37,874 454 — 3,762,515 3,120,370 49,847 22,193 162 3,192,572 Commercial and industrial 2,732,122 18,821 27,763 579 218 2,779,503 2,414,293 7,330 28,965 1,933 2,452,521 Energy-related 656,525 15,827 41,583 — — 713,935 872,842 — 24 — 872,866 Total $ 7,645,964 $ 59,221 $ 108,723 $ 1,033 $ 220 $ 7,815,161 $ 6,891,435 $ 57,417 $ 51,251 $ 2,095 $ 7,002,198 Legacy loans September 30, 2015 December 31, 2014 (Dollars in thousands) Current 30+ Days Past Due Total Current 30+ Days Past Due Total Residential mortgage $ 640,927 $ 19,616 $ 660,543 $ 508,789 $ 18,905 $ 527,694 Consumer - Home equity 1,480,368 8,428 1,488,796 1,278,865 12,111 1,290,976 Consumer - Indirect automobile 277,996 3,526 281,522 392,504 4,262 396,766 Consumer - Credit card 76,018 698 76,716 71,297 1,448 72,745 Consumer - Other 454,361 2,159 456,520 375,853 2,482 378,335 Total $ 2,929,670 $ 34,427 $ 2,964,097 $ 2,627,308 $ 39,208 $ 2,666,516 Non-covered acquired loans September 30, 2015 December 31, 2014 (Dollars in thousands) Pass Special Mention Sub- standard Doubtful Loss Discount Total Pass Special Mention Sub- standard Doubtful Discount Total Commercial real estate-Construction $ 114,684 $ 1,226 $ 8,538 $ 861 $ — $ (1,548 ) $ 123,761 $ 24,118 $ 2,006 $ 4,624 $ — $ (1,170 ) $ 29,578 Commercial real estate - Other 1,434,860 23,421 69,084 3,256 — (39,944 ) 1,490,677 443,450 12,794 49,139 — (39,119 ) 466,264 Commercial and industrial 498,286 3,671 12,905 1,022 539 (4,374 ) 512,049 86,213 1,861 4,807 257 (5,224 ) 87,914 Energy-related 3,358 771 1,392 — — — 5,521 7,731 — 11 — — 7,742 Total $ 2,051,188 $ 29,089 $ 91,919 $ 5,139 $ 539 $ (45,866 ) $ 2,132,008 $ 561,512 $ 16,661 $ 58,581 $ 257 $ (45,513 ) $ 591,498 Non-covered acquired loans September 30, 2015 December 31, 2014 (Dollars in thousands) Current 30+ Days Past Due Premium (discount) Total Current 30+ Days Past Due Premium (discount) Total Residential mortgage $ 407,673 $ 6,401 $ (4,602 ) $ 409,472 $ 418,552 $ 11,858 $ (5,831 ) $ 424,579 Consumer - Home equity 452,928 7,381 (10,644 ) 449,665 216,310 9,808 (8,419 ) 217,699 Consumer - Indirect automobile 142 24 (39 ) 127 393 39 (40 ) 392 Consumer - Other 95,353 1,355 (3,760 ) 92,948 94,315 3,520 (4,217 ) 93,618 Total $ 956,096 $ 15,161 $ (19,045 ) $ 952,212 $ 729,570 $ 25,225 $ (18,507 ) $ 736,288 The Company’s investment in covered loans by credit quality indicator is presented in the following table. Loan premiums/discounts in the tables below represent the adjustment of covered loans to net book value before allowance at the reporting date. Covered loans September 30, 2015 December 31, 2014 (Dollars in thousands) Pass Special Mention Sub- standard Doubtful Total Pass Special Mention Sub- standard Doubtful Total Commercial real estate - Construction $ 113 $ 820 $ 23 $ 1,091 $ 2,047 $ 34,731 $ 1,928 $ 8,008 $ — $ 44,667 Commercial real estate - Other 25,820 1,922 22,705 754 51,201 87,509 20,422 51,252 — 159,183 Commercial and industrial 5,637 810 6,846 2,358 15,651 23,380 395 9,275 — 33,050 $ 31,570 $ 3,552 $ 29,574 $ 4,203 $ 68,899 $ 145,620 $ 22,745 $ 68,535 $ — $ 236,900 Discount (13,890 ) (16,514 ) Total $ 55,009 $ 220,386 Covered loans September 30, 2015 December 31, 2014 30+ Days Premium 30+ Days Premium (Dollars in thousands) Current Total Current Total Residential mortgage $ 128,804 $ 20,672 $ (29,550 ) $ 119,926 $ 140,628 $ 22,058 $ (34,662 ) $ 128,024 Consumer - Home equity 85,772 9,643 (18,189 ) 77,226 99,478 16,542 (23,590 ) 92,430 Consumer - Credit card 542 27 — 569 614 34 — 648 Consumer - Other 216 15 580 811 337 18 2,701 3,056 Total $ 215,334 $ 30,357 $ (47,159 ) $ 198,532 $ 241,057 $ 38,652 $ (55,551 ) $ 224,158
Schedule of Investment in Legacy Impaired Loan	Information on the Company’s investment in legacy impaired loans is presented in the following tables as of and for the periods indicated. September 30, 2015 December 31, 2014 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 16,491 $ 16,491 $ — $ 6,680 $ 6,680 $ — Commercial and industrial 20,360 20,360 — 2,483 2,483 — Energy-related 3,384 3,384 — — — — Consumer - Home equity 214 214 — 682 682 — With an allowance recorded: Commercial real estate 10,681 11,566 (885 ) 1,044 1,069 (25 ) Commercial and industrial 1,009 1,829 (820 ) 1,209 1,617 (408 ) Energy-related 91 94 (3 ) 27 27 — Residential mortgage 14,808 14,879 (71 ) 14,111 14,363 (252 ) Consumer - Home equity 5,248 5,278 (30 ) 7,121 7,165 (44 ) Consumer - Indirect automobile 1,120 1,129 (9 ) 1,410 1,419 (9 ) Consumer - Credit card 329 335 (6 ) 1,012 1,032 (20 ) Consumer - Other 895 920 (25 ) 781 790 (9 ) Total $ 74,630 $ 76,479 $ (1,849 ) $ 36,560 $ 37,327 $ (767 ) Total commercial loans $ 52,016 $ 53,724 $ (1,708 ) $ 11,443 $ 11,876 $ (433 ) Total mortgage loans 14,808 14,879 (71 ) 14,111 14,363 (252 ) Total consumer loans 7,806 7,876 (70 ) 11,006 11,088 (82 ) Three Months Ended Three Months Ended Nine Months Ended Nine Months Ended Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Interest Average Interest (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 16,018 $ 37 $ 7,026 $ 6 $ 16,036 $ 79 7,114 20 Commercial and industrial 20,055 159 3,553 11 20,630 465 4,417 48 Energy-related 3,409 — — — 3,425 — — — Consumer - Home equity 215 3 692 — 204 4 700 14 With an allowance recorded: Commercial real estate 11,649 128 1,631 — 8,247 385 1,533 91 Commercial and industrial 2,121 — 312 — 2,634 — 584 9 Energy-related 99 — — — 106 — — — Residential mortgage 15,008 — 17,305 — 15,100 — 16,341 119 Consumer - Home equity 5,344 — 7,177 5 5,462 — 7,404 40 Consumer - Indirect automobile 1,361 — 1,544 — 1,551 — 1,720 27 Consumer - Credit card 721 — 1,051 — 1,038 — 724 — Consumer - Other 1,030 — 470 — 1,068 — 489 11 Total $ 77,030 $ 327 $ 40,761 $ 22 $ 75,501 $ 933 $ 41,026 $ 379 Total commercial loans $ 53,351 $ 324 $ 12,522 $ 17 $ 51,078 $ 929 $ 13,648 168 Total mortgage loans 15,008 — 17,305 — 15,100 — 16,341 119 Total consumer loans 8,671 3 10,934 5 9,323 4 11,037 92

Loss Sharing Agreements and F30

Loss Sharing Agreements and FDIC Loss Share Receivable (Tables)	9 Months Ended
	Sep. 30, 2015
Loss Sharing Agreements and FDIC Loss Share Receivable [Abstract]
Schedule of FDIC Loss Share Receivables	The following is a summary of FDIC loss share receivables year-to-date activity: Nine Months Ended September 30, (Dollars in thousands) 2015 2014 Balance at beginning of period $ 69,627 $ 162,312 Change due to (reversal of) loan loss provision recorded on FDIC covered loans (1,342 ) 1,153 Amortization (19,011 ) (61,393 ) (Submission of reimbursable losses) recoveries payable to the FDIC (4,084 ) 4,901 Impairment — (5,097 ) Changes due to a change in cash flow assumptions on OREO and other changes (1,747 ) (7,164 ) Balance at end of period $ 43,443 $ 94,712

Goodwill and Other Intangible31

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Carrying Amount of Goodwill	Changes to the carrying amount of goodwill by reporting unit for the nine months ended September 30, 2015, and the year ended December 31, 2014 are provided in the following table. (Dollars in thousands) IBERIABANK IMC LTC Total Balance, December 31, 2013 $ 373,905 $ 23,178 $ 4,789 $ 401,872 Goodwill acquired during the year 115,278 — 376 115,654 Balance, December 31, 2014 $ 489,183 $ 23,178 $ 5,165 $ 517,526 Goodwill acquired during the period 201,937 — — 201,937 Balance, September 30, 2015 $ 691,120 $ 23,178 $ 5,165 $ 719,463
Schedule of Definite-Lived Intangible Assets	Definite-lived intangible assets had the following carrying values included in “Other assets” on the Company’s consolidated balance sheets as of the periods indicated: September 30, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Core deposit intangibles $ 77,941 $ (42,195 ) $ 35,746 $ 55,949 $ (36,354 ) $ 19,595 Customer relationship intangible asset 1,348 (946 ) 402 1,348 (822 ) 526 Non-compete agreement 100 (67 ) 33 163 (82 ) 81 Other intangible assets 205 (97 ) 108 205 (46 ) 159 Total $ 79,594 $ (43,305 ) $ 36,289 $ 57,665 $ (37,304 ) $ 20,361 Mortgage servicing rights had the following carrying values as of the periods indicated: September 30, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Mortgage servicing rights $ 6,110 $ (2,021 ) $ 4,089 $ 4,751 $ (1,253 ) $ 3,498

Derivative Instruments and Ot32

Derivative Instruments and Other Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Derivative Instruments	Information pertaining to outstanding derivative instruments is as follows: (Dollars in thousands) Asset Derivatives Fair Value Liability Derivatives Fair Value Balance Sheet September 30, 2015 December 31, 2014 Balance Sheet September 30, 2015 December 31, 2014 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ — $ — Other liabilities $ 575 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ — $ 575 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ 23,960 $ 15,434 Other liabilities $ 23,960 $ 15,434 Foreign exchange contracts Other assets 4,369 — Other liabilities 4,369 — Forward sales contracts Other assets 452 25 Other liabilities 3,108 2,556 Written and purchased options Other assets 12,659 17,444 Other liabilities 6,135 13,364 Total derivatives not designated as hedging instruments under ASC Topic 815 41,440 32,903 37,572 31,354 Total $ 41,440 $ 32,903 $ 38,147 $ 31,354 (Dollars in thousands) Asset Derivatives Liability Derivatives September 30, 2015 December 31, 2014 September 30, 2015 December 31, 2014 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts $ — $ — $ 108,500 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ — $ 108,500 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts $ 565,820 $ 444,703 $ 565,820 $ 444,703 Foreign exchange contracts 4,392 — 4,370 — Forward sales contracts 55,412 15,897 428,547 391,992 Written and purchased options 361,565 362,580 190,186 225,741 Total derivatives not designated as hedging instruments under ASC Topic 815 987,189 823,180 1,188,923 1,062,436 Total $ 987,189 $ 823,180 $ 1,297,423 $ 1,062,436
Offsetting Assets	The following table reconciles the gross amounts presented in the consolidated balance sheets to the net amounts that would result in the event of offset. September 30, 2015 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 23,959 — — 23,959 Written and purchased options 6,127 — — 6,127 Total derivative assets subject to master netting arrangements $ 30,086 $ — $ — $ 30,086 Derivative liabilities Interest rate contracts designated as hedging instruments 575 — (508 ) 67 Interest rate contracts not designated as hedging instruments 23,959 — (14,704 ) 9,255 Total derivative liabilities subject to master netting arrangements $ 24,534 $ — $ (15,212 ) $ 9,322 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. December 31, 2014 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 15,411 — — 15,411 Written and purchased options 13,387 — — 13,387 Total derivative assets subject to master netting arrangements $ 28,798 $ — $ — $ 28,798 Derivative liabilities Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 15,411 — (3,735 ) 11,676 Total derivative liabilities subject to master netting arrangements $ 15,411 $ — $ (3,735 ) $ 11,676 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities.
Offsetting Liabilities	The following table reconciles the gross amounts presented in the consolidated balance sheets to the net amounts that would result in the event of offset. September 30, 2015 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 23,959 — — 23,959 Written and purchased options 6,127 — — 6,127 Total derivative assets subject to master netting arrangements $ 30,086 $ — $ — $ 30,086 Derivative liabilities Interest rate contracts designated as hedging instruments 575 — (508 ) 67 Interest rate contracts not designated as hedging instruments 23,959 — (14,704 ) 9,255 Total derivative liabilities subject to master netting arrangements $ 24,534 $ — $ (15,212 ) $ 9,322 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. December 31, 2014 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 15,411 — — 15,411 Written and purchased options 13,387 — — 13,387 Total derivative assets subject to master netting arrangements $ 28,798 $ — $ — $ 28,798 Derivative liabilities Interest rate contracts designated as hedging instruments $ — $ — $ — $ — Interest rate contracts not designated as hedging instruments 15,411 — (3,735 ) 11,676 Total derivative liabilities subject to master netting arrangements $ 15,411 $ — $ (3,735 ) $ 11,676 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities.
Effect of Derivatives on Consolidated Financial Statements	At September 30, 2015 and 2014, and for the three and nine months then ended, information pertaining to the effect of the hedging instruments on the consolidated financial statements is as follows: Location of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Gain (Loss) Recognized in OCI net of taxes (Effective Portion) Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) (Dollars in thousands) For the Three Months Ended September 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2015 2014 2015 2014 2015 2014 Interest rate contracts $ (3,412 ) $ — Other income (expense) $ — $ — Other income (expense) $ — $ — Total $ (3,412 ) $ — $ — $ — $ — $ — Location of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Gain (Loss) Recognized in OCI net of taxes (Effective Portion) Location of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion) (Dollars in thousands) For the Nine Months Ended September 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2015 2014 2015 2014 2015 2014 Interest rate contracts $ (374 ) $ — Other income (expense) $ — $ — Other income (expense) $ — $ (1 ) Total $ (374 ) $ — $ — $ — $ — $ (1 ) Information pertaining to the effect of derivatives not designated as hedging instruments on the consolidated financial statements for the three and nine months ended September 30, 2015 is as follows: (Dollars in thousands) Amount of Gain (Loss) Recognized Location of Gain (Loss) For the Three Months Ended September 30 For the Nine Months Ended September 30 2015 2014 2015 2014 Interest rate contracts Other income $ 1,130 $ 406 $ 3,069 $ 1,971 Forward sales contracts Mortgage income (6,524 ) (3,648 ) 1,526 (7,512 ) Written and purchased options Mortgage income (526 ) 773 (1,711 ) 2,401 Total $ (5,920 ) $ (2,469 ) $ 2,884 $ (3,140 )

Shareholders' Equity, Capital33

Shareholders' Equity, Capital Ratios and Other Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2015
Banking and Thrift [Abstract]
Actual Capital Amounts and Ratios	The Company’s and IBERIABANK’s actual capital amounts and ratios as of September 30, 2015 and December 31, 2014 are presented in the following table. September 30, 2015 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 754,230 4.00 % N/A N/A $ 1,758,666 9.33 % IBERIABANK 751,378 4.00 939,222 5.00 1,647,804 8.77 Common Equity Tier 1 (CET1) (1) Consolidated $ 737,629 4.50 % N/A N/A $ 1,652,078 10.08 % IBERIABANK 735,647 4.50 1,062,601 6.50 1,647,804 10.08 Tier 1 Risk-Based Capital (1) Consolidated $ 983,506 6.00 % N/A N/A $ 1,758,666 10.73 % IBERIABANK 980,863 6.00 1,307,817 8.00 1,647,804 10.08 Total Risk-Based Capital (1) Consolidated $ 1,311,341 8.00 % N/A N/A $ 1,990,821 12.15 % IBERIABANK 1,307,817 8.00 1,634,772 10.00 1,792,584 10.97 December 31, 2014 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 602,387 4.00 % N/A N/A $ 1,408,842 9.36 % IBERIABANK 600,149 4.00 750,186 5.00 1,266,241 8.44 Tier 1 Risk-Based Capital Consolidated $ 504,114 4.00 % N/A N/A $ 1,408,842 11.18 % IBERIABANK 502,421 4.00 753,631 6.00 1,266,241 10.08 Total Risk-Based Capital Consolidated $ 1,008,227 8.00 % N/A N/A $ 1,550,789 12.31 % IBERIABANK 1,004,841 8.00 1,256,052 10.00 1,408,188 11.21 (1) Beginning January 1, 2016, minimum capital ratios will be subject to a capital conservation buffer of 0.625% . This capital conservation buffer will increase in subsequent years by 0.625% annually until it is fully phased in on January 1, 2019 at 2.50% .

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Earnings Per Share	The following table presents the calculation of basic and diluted earnings per share for the periods indicated. Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share data) 2015 2014 2015 2014 Earnings per common share - basic Net income $ 42,475 $ 30,893 $ 98,437 $ 69,445 Dividends and undistributed earnings allocated to unvested restricted shares (492 ) (462 ) (1,171 ) (1,114 ) Net income allocated to common shareholders - basic $ 41,983 $ 30,431 $ 97,266 $ 68,331 Weighted average common shares outstanding 40,514 32,803 37,436 30,791 Earnings per common share - basic $ 1.04 $ 0.93 $ 2.60 $ 2.22 Earnings per common share - diluted Net income allocated to common shareholders - basic $ 41,983 $ 30,431 $ 97,266 $ 68,331 Dividends and undistributed earnings allocated to unvested restricted shares (3 ) (4 ) (41 ) (24 ) Net income allocated to common shareholders - diluted $ 41,980 $ 30,427 $ 97,225 $ 68,307 Weighted average common shares outstanding 40,514 32,803 37,436 30,791 Dilutive potential common shares - stock options 100 124 96 132 Weighted average common shares outstanding - diluted 40,614 32,927 37,532 30,923 Earnings per common share - diluted $ 1.03 $ 0.92 $ 2.59 $ 2.21

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award
Activity Related to Stock Options	The following table represents the activity related to stock options during the periods indicated: Number of shares Weighted Average Exercise Price Outstanding options, December 31, 2014 867,682 $ 55.92 Granted 81,313 62.53 Exercised (95,265 ) 50.64 Forfeited or expired (15,733 ) 66.57 Outstanding options, September 30, 2015 837,997 $ 56.96 Exercisable options, September 30, 2015 570,148 $ 56.53 Outstanding options, December 31, 2013 1,072,829 $ 53.47 Granted 77,098 65.30 Exercised (234,363 ) 48.36 Forfeited or expired (13,446 ) 60.82 Outstanding options, September 30, 2014 902,118 $ 55.70 Exercisable options, September 30, 2014 581,423 $ 55.65
Estimate Fair Value of Share Option Awards with Weighted-Average Assumptions	The Company uses the Black-Scholes option pricing model to estimate the fair value of stock option awards. The following weighted-average assumptions were used for option awards issued during the nine-month periods ended September 30: 2015 2014 Expected dividends 2.2 % 2.1 % Expected volatility 35.6 % 35.8 % Risk-free interest rate 2.0 % 2.3 % Expected term (in years) 7.5 7.5 Weighted-average grant-date fair value $ 19.60 $ 21.25
Unvested Restricted Stock Award and Restricted Share Unit Activity	The following table represents unvested restricted stock award and restricted share unit activity for the nine months ended September 30: 2015 2014 Balance at beginning of period 506,289 523,756 Granted 203,762 165,634 Forfeited (23,471 ) (18,171 ) Earned and issued (170,513 ) (152,112 ) Balance at end of period 516,067 519,107
Schedule of Share and Dividend Equivalent Share Award Activity	The following table represents phantom stock award and performance unit activity during the periods indicated: Number of share equivalents Dividend equivalents Total share equivalents Value of share equivalents (1) Balance, December 31, 2014 460,212 22,648 482,860 $ 31,313,000 Granted 156,505 7,261 163,766 9,533,000 Forfeited share equivalents (29,180 ) (1,541 ) (30,721 ) (1,788,000 ) Vested share equivalents (130,380 ) (9,134 ) (139,514 ) (8,829,000 ) Balance, September 30, 2015 457,157 19,234 476,391 $ 27,731,000 Balance, December 31, 2013 417,238 22,351 439,589 $ 27,628,000 Granted 115,620 7,147 122,767 7,674,000 Forfeited share equivalents (19,498 ) (1,751 ) (21,249 ) (1,328,000 ) Vested share equivalents (68,480 ) (6,615 ) (75,095 ) (5,002,000 ) Balance, September 30, 2014 444,880 21,132 466,012 $ 29,130,000 (1) Except for share equivalents at the beginning of each period, which are based on the value at that time, and vested share payments, which are based on the cash paid at the time of vesting, the value of share equivalents is calculated based on the market price of the Company’s stock at the end of the respective periods. The market price of the Company’s stock was $58.21 and $62.51 on September 30, 2015 , and 2014 , respectively.
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Compensation Expense Included in Non-Interest Expense	The following table represents the compensation expense that is included in non-interest expense in the accompanying consolidated statements of comprehensive income related to stock options for the three-month and nine-month periods ended September 30: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2015 2014 2015 2014 Compensation expense related to stock options $ 455 $ 508 $ 1,400 $ 1,545
Restricted Stock Awards and Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Compensation Expense Included in Non-Interest Expense	The following table represents the compensation expense that was included in non-interest expense in the accompanying consolidated statements of comprehensive income related to restricted stock awards and restricted share units for the three-month and nine-month periods ended September 30: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2015 2014 2015 2014 Compensation expense related to restricted stock awards and restricted share units $ 2,935 $ 2,497 $ 8,739 $ 7,382
Phantom Stock and Performance Units
Share-based Compensation Arrangement by Share-based Payment Award
Compensation Expense Included in Non-Interest Expense	The following table indicates compensation expense recorded for phantom stock and performance units based on the number of share equivalents vested at September 30 of the periods indicated and the current market price of the Company’s stock at that time: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2015 2014 2015 2014 Compensation expense related to phantom stock and performance units $ 2,976 $ 619 $ 9,482 $ 3,692

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Financial Asset and Liabilities Measured at Fair Value on Recurring Basis	The Company has segregated all financial assets and liabilities that are measured at fair value on a recurring basis into the most appropriate level within the fair value hierarchy based on the inputs used to estimate the fair value at the measurement date in the tables below. September 30, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,827,805 $ — $ 2,827,805 Mortgage loans held for sale — 202,168 — 202,168 Derivative instruments — 41,440 — 41,440 Total $ — $ 3,071,413 $ — $ 3,071,413 Liabilities Derivative instruments $ — $ 38,147 $ — $ 38,147 Total $ — $ 38,147 $ — $ 38,147 December 31, 2014 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,158,853 $ — $ 2,158,853 Mortgage loans held for sale — 139,950 — 139,950 Derivative instruments — 32,903 — 32,903 Total $ — $ 2,331,706 $ — $ 2,331,706 Liabilities Derivative instruments $ — $ 31,354 $ — $ 31,354 Total $ — $ 31,354 $ — $ 31,354
Gains and Losses Included in Earnings Related to Asset and Liabilities Measured at Fair Value on Recurring Basis	Gains and losses (realized and unrealized) included in earnings (or accumulated other comprehensive income) during the first nine months of 2015 related to assets and liabilities measured at fair value on a recurring basis are reported in non-interest income or other comprehensive income as follows: (Dollars in thousands) Non-interest Other Net gains included in earnings $ 2,643 $ — Change in unrealized net gains relating to assets still held at September 30, 2015 — 9,458
Financial Asset and Liabilities Measured at Fair Value on Nonrecurring Basis	The Company has segregated all financial assets and liabilities that are measured at fair value on a non-recurring basis into the most appropriate level within the fair value hierarchy based on the inputs used to determine the fair value at the measurement date in the tables below. September 30, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets OREO, net $ — $ 1,904 $ — $ 1,904 Total $ — $ 1,904 $ — $ 1,904 December 31, 2014 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets OREO, net $ — $ 1,483 $ — $ 1,483 Total $ — $ 1,483 $ — $ 1,483
Summary of Difference Between the Aggregate Fair Value and the Aggregate Unpaid Principal Balance for Mortgage Loans Held for Sale	The following table summarizes the difference between the aggregate fair value and the aggregate unpaid principal balance for mortgage loans held for sale measured at fair value: September 30, 2015 December 31, 2014 (Dollars in thousands) Aggregate Aggregate Aggregate Aggregate Aggregate Aggregate Mortgage loans held for sale, at fair value $ 202,168 $ 194,376 $ 7,792 $ 139,950 $ 134,639 $ 5,311

Fair Value of Financial Instr37

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Estimated Fair Values and Carrying Amounts of Financial Instruments	The carrying amount and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments are as follows: September 30, 2015 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 682,272 $ 682,272 $ 682,272 $ — $ — Investment securities 2,926,135 2,928,416 — 2,928,416 — Loans and loans held for sale, net of unearned income and allowance for loan losses 14,188,933 14,637,107 — 212,764 14,424,343 FDIC loss share receivables 43,443 8,437 — — 8,437 Derivative instruments 41,440 41,440 — 41,440 — Financial Liabilities Deposits $ 16,303,065 $ 15,996,499 $ — $ — $ 15,996,499 Short-term borrowings 222,460 222,460 222,460 — — Long-term debt 341,973 311,982 — — 311,982 Derivative instruments 38,147 38,147 — 38,147 — December 31, 2014 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 548,095 $ 548,095 $ 548,095 $ — $ — Investment securities 2,275,813 2,278,334 — 2,278,334 — Loans and loans held for sale, net of unearned income and allowance for loan losses 11,450,985 11,475,315 — 139,950 11,335,365 FDIC loss share receivables 69,627 19,606 — — 19,606 Derivative instruments 32,903 32,903 — 32,903 — Financial Liabilities Deposits $ 12,520,525 $ 12,298,017 $ — $ — $ 12,298,017 Short-term borrowings 845,742 845,742 845,742 — — Long-term debt 403,254 376,139 — — 376,139 Derivative instruments 31,354 31,354 — 31,354 —

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	Three Months Ended September 30, 2015 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 169,005 $ 2,071 $ 1 $ 171,077 Interest expense 15,109 851 — 15,960 Net interest income 153,896 1,220 1 155,117 Provision for loan losses 5,062 — — 5,062 Mortgage income 365 20,365 — 20,730 Title revenue — — 6,627 6,627 Other non-interest income 30,120 1 — 30,121 Allocated expenses (3,518 ) 2,693 825 — Non-interest expense 124,909 15,605 4,454 144,968 Income before income tax expense 57,928 3,288 1,349 62,565 Income tax expense 18,253 1,306 531 20,090 Net income $ 39,675 $ 1,982 $ 818 $ 42,475 Total loans and loans held for sale $ 14,094,936 $ 224,251 $ — $ 14,319,187 Total assets 19,242,690 264,914 26,621 19,534,225 Total deposits 16,293,681 9,384 — 16,303,065 Average assets 19,321,164 256,897 26,009 19,604,070 Three Months Ended September 30, 2014 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 131,987 $ 1,805 $ 1 $ 133,793 Interest expense 11,416 626 — 12,042 Net interest income 120,571 1,179 1 121,751 Provision for loan losses 5,621 93 — 5,714 Mortgage income (4 ) 14,267 — 14,263 Title revenue — — 5,577 5,577 Other non-interest income 27,310 (36 ) (2 ) 27,272 Allocated expenses (2,386 ) 1,697 689 — Non-interest expense 104,172 11,624 4,316 120,112 Income before income tax expense 40,470 1,996 571 43,037 Income tax expense 11,128 785 231 12,144 Net income $ 29,342 $ 1,211 $ 340 $ 30,893 Total loans and loans held for sale $ 11,057,497 $ 171,920 $ — $ 11,229,417 Total assets 15,288,142 200,778 25,529 15,514,449 Total deposits 12,371,522 6,169 — 12,377,691 Average assets 15,240,567 210,345 25,296 15,476,208 Nine Months Ended September 30, 2015 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 464,775 $ 5,430 $ 2 $ 470,207 Interest expense 41,410 2,199 — 43,609 Net interest income 423,365 3,231 2 426,598 Provision for loan losses 19,197 — — 19,197 Mortgage income 932 63,067 — 63,999 Title revenue — — 17,402 17,402 Other non-interest income 86,498 (2 ) (7 ) 86,489 Allocated expenses (11,603 ) 8,685 2,918 — Non-interest expense 373,948 44,259 13,123 431,330 Income before income tax expense 129,253 13,352 1,356 143,961 Income tax expense 39,695 5,286 543 45,524 Net income $ 89,558 $ 8,066 $ 813 $ 98,437 Total loans and loans held for sale $ 14,094,936 $ 224,251 $ — $ 14,319,187 Total assets 19,242,690 264,914 26,621 19,534,225 Total deposits 16,293,681 9,384 — 16,303,065 Average assets 17,760,033 230,379 25,268 18,015,680 Nine Months Ended September 30, 2014 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 362,974 $ 4,563 $ 2 $ 367,539 Interest expense 30,784 1,323 — 32,107 Net interest income 332,190 3,240 2 335,432 Provision for loan losses 12,481 84 — 12,565 Mortgage income 80 38,070 — 38,150 Title revenue — — 15,007 15,007 Other non-interest income 73,459 (60 ) (2 ) 73,397 Allocated expenses (9,110 ) 6,432 2,678 — Non-interest expense 308,515 33,558 12,406 354,479 Income (loss) before income tax expense 93,843 1,176 (77 ) 94,942 Income tax expense (benefit) 25,038 473 (14 ) 25,497 Net income (loss) $ 68,805 $ 703 $ (63 ) $ 69,445 Total loans and loans held for sale $ 11,057,497 $ 171,920 $ — $ 11,229,417 Total assets 15,288,142 200,778 25,529 15,514,449 Total deposits 12,371,522 6,169 — 12,377,691 Average assets 14,097,954 177,995 25,003 14,300,952

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Summary of Financial Instruments Outstanding	The Company had the following financial instruments outstanding, whose contract amounts represent credit risk: (Dollars in thousands) September 30, 2015 December 31, 2014 Commitments to grant loans $ 140,139 $ 161,350 Unfunded commitments under lines of credit 4,602,464 4,007,954 Commercial and standby letters of credit 147,208 134,882 Reserve for unfunded lending commitments 14,525 11,801

Basis of Presentation (Detail)

Basis of Presentation (Detail)	Sep. 30, 2015State
IBERIABANK
Schedule Of Significant Accounting Policies
Number of states with operations	7
IMC
Schedule Of Significant Accounting Policies
Number of states with operations	10

Acquisition Activity (Detail)

Acquisition Activity (Detail) $ / shares in Units, $ in Thousands	May. 31, 2015USD ($)Branchshares	Mar. 31, 2015USD ($)Branchshares	Feb. 28, 2015USD ($)Branch$ / sharesshares	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Business Acquisition
Goodwill				$ 719,463	$ 517,526	$ 401,872
Maximum period for subject to change estimated fair values after acquisition date				1 year
Florida Bank Group, Inc.
Business Acquisition
Cash received per share | $ / shares			$ 7.81
Shares received | shares			0.149
Total consideration paid			$ 90,485
Goodwill			$ 16,749
Number of bank offices | Branch			12
Old Florida Bancshares, Inc.
Business Acquisition
Shares received | shares		0.34
Total consideration paid		$ 253,152
Goodwill		$ 99,531
Number of bank offices | Branch		14
Georgia Commerce Bancshares, Inc.
Business Acquisition
Shares received | shares	0.6134
Total consideration paid	$ 190,264
Goodwill	$ 81,240
Number of bank offices | Branch	9

Acquisition Activity - Schedule

Acquisition Activity - Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable (Detail) - USD ($) $ in Thousands	May. 31, 2015	Mar. 31, 2015	Feb. 28, 2015	Sep. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Non-Equity consideration
Goodwill				$ 719,463	$ 517,526	$ 401,872
Florida Bank Group, Inc.
Equity consideration
Common stock issued (shares)			752,493
Total equity consideration			$ 47,497
Non-Equity consideration
Cash			42,988
Total consideration paid			90,485
Fair value of net assets assumed including identifiable intangible assets			73,736
Goodwill			$ 16,749
Old Florida Bancshares, Inc.
Equity consideration
Common stock issued (shares)		3,839,554
Total equity consideration		$ 242,007
Non-Equity consideration
Cash		11,145
Total consideration paid		253,152
Fair value of net assets assumed including identifiable intangible assets		153,621
Goodwill		$ 99,531
Georgia Commerce Bancshares, Inc.
Equity consideration
Common stock issued (shares)	2,882,357
Total equity consideration	$ 185,249
Non-Equity consideration
Cash	5,015
Total consideration paid	190,264
Fair value of net assets assumed including identifiable intangible assets	109,024
Goodwill	$ 81,240

Acquisition Activity - Schedu43

Acquisition Activity - Schedule of Business Acquisitions, by Acquisition (Detail) - USD ($) $ in Thousands	May. 31, 2015	Mar. 31, 2015	Feb. 28, 2015	Sep. 30, 2015
Florida Bank Group, Inc.
Assets
Cash and cash equivalents			$ 72,982	$ 72,982
Investment securities			107,236	107,372
Loans			312,902	305,829
Other real estate owned			498	423
Core deposit intangible			0	4,489
Deferred tax asset, net			19,889	29,121
Other assets			29,810	20,861
Total Assets			543,317	541,077
Liabilities
Interest-bearing deposits			282,417	282,680
Non-interest-bearing deposits			109,548	109,548
Borrowings			60,000	68,598
Other liabilities			1,897	6,515
Total Liabilities			$ 453,862	467,341
Estimated amortized period for fair value adjustment			51 months
Old Florida Bancshares, Inc.
Assets
Cash and cash equivalents		$ 360,688		360,688
Investment securities		67,209		67,209
Loans held for sale		5,952		5,952
Loans		1,073,773		1,064,431
Other real estate owned		4,515		4,513
Core deposit intangible		0		10,055
Deferred tax asset, net		8,470		11,651
Other assets		30,732		23,494
Total Assets		1,551,339		1,547,993
Liabilities
Interest-bearing deposits		1,048,765		1,048,888
Non-interest-bearing deposits		340,869		340,869
Borrowings		1,528		1,528
Other liabilities		3,011		3,087
Total Liabilities		$ 1,394,173		1,394,372
Estimated amortized period for fair value adjustment		56 months
Georgia Commerce Bancshares, Inc.
Assets
Cash and cash equivalents	$ 51,059			51,059
Investment securities	139,035			138,229
Loans held for sale	1,249			1,249
Loans	807,726			801,104
Other real estate owned	9,795			5,613
Core deposit intangible	0			7,448
Deferred tax asset, net	5,030			6,879
Other assets	30,587			29,930
Total Assets	1,044,481			1,041,511
Liabilities
Interest-bearing deposits	658,133			658,309
Non-interest-bearing deposits	249,739			249,739
Borrowings	13,203			13,203
Other liabilities	11,236			11,236
Total Liabilities	$ 932,311			932,487
Estimated amortized period for fair value adjustment	60 months
Preliminary Fair Value Adjustment | Florida Bank Group, Inc.
Assets
Cash and cash equivalents			$ 0
Investment securities			136
Loans			(7,073)
Other real estate owned			(75)
Core deposit intangible			4,489
Deferred tax asset, net			9,232
Other assets			(8,949)
Total Assets			(2,240)
Liabilities
Interest-bearing deposits			263
Non-interest-bearing deposits			0
Borrowings			8,598
Other liabilities			4,618
Total Liabilities			$ 13,479
Preliminary Fair Value Adjustment | Old Florida Bancshares, Inc.
Assets
Cash and cash equivalents		$ 0
Investment securities		0
Loans held for sale		0
Loans		(9,342)
Other real estate owned		(2)
Core deposit intangible		10,055
Deferred tax asset, net		3,181
Other assets		(7,238)
Total Assets		(3,346)
Liabilities
Interest-bearing deposits		123
Non-interest-bearing deposits		0
Borrowings		0
Other liabilities		76
Total Liabilities		$ 199
Preliminary Fair Value Adjustment | Georgia Commerce Bancshares, Inc.
Assets
Cash and cash equivalents				0
Investment securities				(806)
Loans held for sale				0
Loans				(6,622)
Other real estate owned				(4,182)
Core deposit intangible				7,448
Deferred tax asset, net				1,849
Other assets				(657)
Total Assets				(2,970)
Liabilities
Interest-bearing deposits				176
Non-interest-bearing deposits				0
Borrowings				0
Other liabilities				0
Total Liabilities				$ 176

Acquisition Activity - Suppleme

Acquisition Activity - Supplemental Pro Forma Information (Detail) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2014USD ($)$ / shares
Business Acquisition, Pro Forma Information [Abstract]
Interest and non-interest income | $	$ 586,979
Net income | $	$ 88,615
Earnings per share - basic (in usd per share)	$ 2.28
Earnings per share - diluted (in usd per share)	$ 2.28

Investment Securities (Detail)

Investment Securities (Detail) $ in Billions	Sep. 30, 2015USD ($)Security	Dec. 31, 2014USD ($)Security
Net Investment Income
Carrying value of pledged securities | $	$ 1.3	$ 1.4
Number of debt securities held	103	112
Unrealized losses on debt securities (percent of amortized cost)	0.89%	1.31%
Obligations of States and Political Subdivisions
Net Investment Income
Number of securities in a continuous loss position for over twelve months	2

Investment Securities - Schedul

Investment Securities - Schedule of Amortized Cost and Fair Values of Investment Securities, with Gross Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities
Amortized cost	$ 98,330	$ 116,960
Gross unrealized gains	2,981	3,392
Gross unrealized losses	(700)	(871)
Estimated fair value	100,611	119,481
Schedule of Available-for-sale Securities
Amortized cost	2,801,751	2,147,276
Gross Unrealized Gains	30,096	22,296
Gross Unrealized Losses	(4,042)	(10,719)
Securities available for sale	2,827,805	2,158,853
U.S. Government-Sponsored Enterprise Obligations
Schedule of Held-to-maturity Securities
Amortized cost		10,000
Gross unrealized gains		88
Gross unrealized losses		0
Estimated fair value		10,088
Schedule of Available-for-sale Securities
Amortized cost	277,822	317,386
Gross Unrealized Gains	2,743	1,700
Gross Unrealized Losses	(45)	(3,533)
Securities available for sale	280,520	315,553
Obligations of States and Political Subdivisions
Schedule of Held-to-maturity Securities
Amortized cost	73,821	77,597
Gross unrealized gains	2,878	3,153
Gross unrealized losses	(74)	(145)
Estimated fair value	76,625	80,605
Schedule of Available-for-sale Securities
Amortized cost	181,626	86,513
Gross Unrealized Gains	4,502	3,679
Gross Unrealized Losses	0	(2)
Securities available for sale	186,128	90,190
Mortgage-Backed Securities
Schedule of Held-to-maturity Securities
Amortized cost	24,509	29,363
Gross unrealized gains	103	151
Gross unrealized losses	(626)	(726)
Estimated fair value	23,986	28,788
Schedule of Available-for-sale Securities
Amortized cost	2,246,002	1,741,917
Gross Unrealized Gains	22,157	16,882
Gross Unrealized Losses	(3,647)	(7,184)
Securities available for sale	2,264,512	1,751,615
Other Securities
Schedule of Available-for-sale Securities
Amortized cost	96,301	1,460
Gross Unrealized Gains	694	35
Gross Unrealized Losses	(350)	0
Securities available for sale	$ 96,645	$ 1,495

Investment Securities - Sched47

Investment Securities - Schedule of Securities with Gross Unrealized Losses Aggregated by Investment Category (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Gross Unrealized Losses
Less than twelve months	$ (23)	$ (9)
Over twelve months	(677)	(862)
Total	(700)	(871)
Estimated Fair Value
Less than twelve months	4,696	2,287
Over twelve months	22,485	29,402
Total	27,181	31,689
Gross Unrealized Losses
Less than twelve months	(1,300)	(1,191)
Over twelve months	(2,742)	(9,528)
Total	(4,042)	(10,719)
Estimated Fair Value
Less than twelve months	279,984	304,871
Over twelve months	220,790	535,047
Total	500,774	839,918
U.S. Government-Sponsored Enterprise Obligations
Gross Unrealized Losses
Less than twelve months	0	0
Over twelve months	(45)	(3,533)
Total	(45)	(3,533)
Estimated Fair Value
Less than twelve months	0	0
Over twelve months	28,449	240,498
Total	28,449	240,498
Obligations of States and Political Subdivisions
Gross Unrealized Losses
Less than twelve months	(6)	(9)
Over twelve months	(68)	(136)
Total	(74)	(145)
Estimated Fair Value
Less than twelve months	3,642	2,287
Over twelve months	4,199	8,590
Total	7,841	10,877
Gross Unrealized Losses
Less than twelve months		(2)
Over twelve months		0
Total		(2)
Estimated Fair Value
Less than twelve months		185
Over twelve months		0
Total		185
Mortgage-Backed Securities
Gross Unrealized Losses
Less than twelve months	(17)	0
Over twelve months	(609)	(726)
Total	(626)	(726)
Estimated Fair Value
Less than twelve months	1,054	0
Over twelve months	18,286	20,812
Total	19,340	20,812
Gross Unrealized Losses
Less than twelve months	(954)	(1,189)
Over twelve months	(2,693)	(5,995)
Total	(3,647)	(7,184)
Estimated Fair Value
Less than twelve months	252,358	304,686
Over twelve months	191,836	294,549
Total	444,194	$ 599,235
Other Securities
Gross Unrealized Losses
Less than twelve months	(346)
Over twelve months	(4)
Total	(350)
Estimated Fair Value
Less than twelve months	27,626
Over twelve months	505
Total	$ 28,131

Investment Securities - Additio

Investment Securities - Additional Information on Securities in a Continuous Loss Position (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015USD ($)Security	Dec. 31, 2014USD ($)Security
Schedule of Available-for-sale Securities
Number of securities | Security	42	71
Amortized cost basis	$ 246,694	$ 574,840
Unrealized loss	$ 3,419	$ 10,390
Issued by Fannie Mae, Freddie Mac, or Ginnie Mae
Schedule of Available-for-sale Securities
Number of securities | Security	39	66
Amortized cost basis	$ 241,918	$ 566,113
Unrealized loss	$ 3,347	$ 10,254
Issued by Political Subdivisions
Schedule of Available-for-sale Securities
Number of securities | Security	2	5
Amortized cost basis	$ 4,267	$ 8,727
Unrealized loss	$ 68	$ 136
Others
Schedule of Available-for-sale Securities
Number of securities | Security	1	0
Amortized cost basis	$ 509	$ 0
Unrealized loss	$ 4	$ 0

Investment Securities - Sched49

Investment Securities - Schedule of Amortized Cost and Estimated Fair Value of Investment Securities by Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Weighted Average Yield
Within one year or less	1.63%
One through five years	1.69%
After five through ten years	2.23%
Over ten years	2.12%
Weighted average yield	2.09%
Amortized Cost
Within one year or less	$ 25,724
One through five years	298,322
After five through ten years	516,467
Over ten years	1,961,238
Amortized Cost	2,801,751
Estimated Fair Value
Within one year or less	25,824
One through five years	301,724
After five through ten years	524,969
Over ten years	1,975,288
Estimated fair value	$ 2,827,805	$ 2,158,853
Weighted Average Yield
Within one year or less	3.85%
One through five years	2.79%
After five through ten years	3.09%
Over ten years	2.98%
Weighted average yield	2.98%
Amortized Cost
Within one year or less	$ 75
One through five years	11,552
After five through ten years	20,663
Over ten years	66,040
Amortized cost	98,330	116,960
Estimated Fair Value
Within one year or less	75
One through five years	11,808
After five through ten years	21,494
Over ten years	67,234
Estimated fair value	$ 100,611	$ 119,481

Investment Securities - Sched50

Investment Securities - Schedule of Realized Gains and Losses from Sale of Securities Classified as Available for Sale (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]
Realized gains	$ 425	$ 582	$ 1,786	$ 609
Realized losses	(145)	0	(217)	0
Net realized gains (losses)	$ 280	$ 582	$ 1,569	$ 609

Investment Securities - Sched51

Investment Securities - Schedule of Securities in Other Assets on Company's Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Federal Home Loan Bank (FHLB) stock	$ 14,603	$ 38,476
Federal Reserve Bank (FRB) stock	48,584	34,348
Other investments	1,158	1,306
Total	$ 64,345	$ 74,130

Loans (Detail)

Loans (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)bank	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Accounts, Notes, Loans and Financing Receivable
Failed banks acquired since 2009 | bank	6
Deferred loan origination fees	$ 26.3		$ 20.6
Deferred loan expenses	10.7		9.4
Deposit liabilities reclassified as loans receivable	5.2		5.6
Loans with carrying value pledged to secure public deposits and other borrowings	$ 4,000		$ 3,100
Carrying amounts of loans acquired		$ 2,200
Threshold period for loans in default	30 days
Troubled Debt Restructurings
Accounts, Notes, Loans and Financing Receivable
Total TDRs	$ 48.6
Energy related TDR	3.4
Accrual status TDR	$ 21.8
Florida Bank Group, Inc.
Accounts, Notes, Loans and Financing Receivable
Acquired loans		300
Old Florida Bancshares, Inc.
Accounts, Notes, Loans and Financing Receivable
Acquired loans		1,100
Georgia Commerce
Accounts, Notes, Loans and Financing Receivable
Acquired loans		800
Loans Acquired Without Deteriorated Credit Quality
Accounts, Notes, Loans and Financing Receivable
Carrying amounts of loans acquired		2,100
Loans Acquired With Deteriorated Credit Quality
Accounts, Notes, Loans and Financing Receivable
Carrying amounts of loans acquired		$ 41.1

Loans - Schedule of Non-Covered

Loans - Schedule of Non-Covered and Covered Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014		Sep. 30, 2015	Sep. 30, 2014
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	$ 10,996,500		$ 13,863,478
Covered loans receivable	444,544		253,541
Total loans, net of unearned income	11,441,044		14,117,019
Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	7,814,082		10,002,178
Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	4,361,779		5,979,751
Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	2,571,695		3,302,971
Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	880,608		719,456
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,080,297		1,189,941
Residential Mortgage Loans | Residential 1-4 Family
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,048,241		1,114,752
Residential Mortgage Loans | Construction / Owner Occupied
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	32,056		75,189
Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	2,546,665		2,924,900
Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,601,105		2,015,687
Consumer and Other Loans | Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	397,158		281,649
Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	548,402		627,564
Non-Covered Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	9,668,714		10,779,258
Non-Covered Legacy Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	7,002,198		7,815,161
Non-Covered Legacy Loans | Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	3,676,811		4,321,723
Non-Covered Legacy Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	2,452,521		2,779,503
Non-Covered Legacy Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	872,866		713,935
Non-Covered Legacy Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	527,694		660,543
Non-Covered Legacy Loans | Residential Mortgage Loans | Residential 1-4 Family
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	495,638		596,428
Non-Covered Legacy Loans | Residential Mortgage Loans | Construction / Owner Occupied
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	32,056		64,115
Non-Covered Legacy Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	2,138,822		2,303,554
Non-Covered Legacy Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	1,290,976		1,488,796
Non-Covered Legacy Loans | Consumer and Other Loans | Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	396,766		281,522
Non-Covered Legacy Loans | Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	451,080		533,236
Non-Covered Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	1,327,786		3,084,220
Non-Covered Acquired Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	591,498		2,132,008
Non-Covered Acquired Loans | Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	495,842		1,614,438
Non-Covered Acquired Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	87,914		512,049
Non-Covered Acquired Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	7,742		5,521
Non-Covered Acquired Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	424,579		409,472
Non-Covered Acquired Loans | Residential Mortgage Loans | Residential 1-4 Family
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	424,579		398,398
Non-Covered Acquired Loans | Residential Mortgage Loans | Construction / Owner Occupied
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	0		11,074
Non-Covered Acquired Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	311,709		542,740
Non-Covered Acquired Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	217,699		449,665
Non-Covered Acquired Loans | Consumer and Other Loans | Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	392		127
Non-Covered Acquired Loans | Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	93,618		92,948
Covered Loans
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	444,544	[1]	253,541	$ 524,189
Assets whose reimbursable loss period ended January 1, 2015	174,700
Covered Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	220,386	[1]	55,009
Covered Loans | Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	189,126	[1]	43,590	247,156
Covered Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	31,260	[1]	11,419	34,234
Covered Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	0	[1]	0
Covered Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	128,024	[1]	119,926	130,976
Covered Loans | Residential Mortgage Loans | Residential 1-4 Family
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	128,024	[1]	119,926
Covered Loans | Residential Mortgage Loans | Construction / Owner Occupied
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	0	[1]	0
Covered Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	96,134	[1]	78,606	$ 111,823
Covered Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	92,430	[1]	77,226
Covered Loans | Consumer and Other Loans | Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	0	[1]	0
Covered Loans | Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	$ 3,704	[1]	$ 1,380
[1]	Included as covered loans at December 31, 2014 is $174.7 million of assets whose reimbursable loss periods ended as of January 1, 2015.

Loans - Schedule of Aging of No

Loans - Schedule of Aging of Non-Covered Loans (Detail) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015		Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable
Discount (premium)		$ 26,300		$ 20,600
Non-covered loans, net of unearned income		$ 13,863,478		10,996,500
Past due loans threshold period		90 days
Non-Covered Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	$ 9,450		23,365
Past due, 60-89 days	[1]	6,267		6,202
Past due, greater than 90 days	[1]	52,795		35,724
Total past due	[1]	68,512		65,291
Current		10,710,746		9,603,423
Non-covered loans, net of unearned income		10,779,258		9,668,714
Recorded investment greater than 90 days and accruing		1,521		754
Non-Covered Legacy Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income		7,815,161		7,002,198
Non-Covered Legacy Loans | Commercial Loans | Commercial Real Estate - Construction
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	0		507
Past due, 60-89 days	[1]	0		0
Past due, greater than 90 days	[1]	180		69
Total past due	[1]	180		576
Current		559,028		483,663
Non-covered loans, net of unearned income		559,208		484,239
Recorded investment greater than 90 days and accruing		0		0
Non-Covered Legacy Loans | Commercial Loans | Commercial Real Estate - Other
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	1,225		11,799
Past due, 60-89 days	[1]	1,763		148
Past due, greater than 90 days	[1]	14,541		6,859
Total past due	[1]	17,529		18,806
Current		3,744,986		3,173,766
Non-covered loans, net of unearned income		3,762,515		3,192,572
Recorded investment greater than 90 days and accruing		242		0
Non-Covered Legacy Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	1,087		1,589
Past due, 60-89 days	[1]	672		1,860
Past due, greater than 90 days	[1]	11,139		3,225
Total past due	[1]	12,898		6,674
Current		2,766,605		2,445,847
Non-covered loans, net of unearned income		2,779,503		2,452,521
Recorded investment greater than 90 days and accruing		363		200
Non-Covered Legacy Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	0		0
Past due, 60-89 days	[1]	0		0
Past due, greater than 90 days	[1]	3,478		27
Total past due	[1]	3,478		27
Current		710,457		872,839
Non-covered loans, net of unearned income		713,935		872,866
Recorded investment greater than 90 days and accruing		0		0
Non-Covered Legacy Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income		660,543		527,694
Non-Covered Legacy Loans | Residential Mortgage Loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	1,832		1,389
Past due, 60-89 days	[1]	2,054		2,616
Past due, greater than 90 days	[1]	15,730		14,900
Total past due	[1]	19,616		18,905
Current		640,927		508,789
Non-covered loans, net of unearned income		660,543		527,694
Recorded investment greater than 90 days and accruing		851		538
Non-Covered Legacy Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income		2,303,554		2,138,822
Non-Covered Legacy Loans | Consumer and Other Loans | Consumer - Home Equity
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	2,232		4,096
Past due, 60-89 days	[1]	853		595
Past due, greater than 90 days	[1]	5,343		7,420
Total past due	[1]	8,428		12,111
Current		1,480,368		1,278,865
Non-covered loans, net of unearned income		1,488,796		1,290,976
Recorded investment greater than 90 days and accruing		65		16
Non-Covered Legacy Loans | Consumer and Other Loans | Consumer - Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	1,927		2,447
Past due, 60-89 days	[1]	470		396
Past due, greater than 90 days	[1]	1,129		1,419
Total past due	[1]	3,526		4,262
Current		277,996		392,504
Non-covered loans, net of unearned income		281,522		396,766
Recorded investment greater than 90 days and accruing		0		0
Non-Covered Legacy Loans | Consumer and Other Loans | Consumer - Credit Card
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	247		253
Past due, 60-89 days	[1]	116		163
Past due, greater than 90 days	[1]	335		1,032
Total past due	[1]	698		1,448
Current		76,018		71,297
Non-covered loans, net of unearned income		76,716		72,745
Recorded investment greater than 90 days and accruing		0		0
Non-Covered Legacy Loans | Consumer and Other Loans | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[1]	900		1,285
Past due, 60-89 days	[1]	339		424
Past due, greater than 90 days	[1]	920		773
Total past due	[1]	2,159		2,482
Current		454,361		375,853
Non-covered loans, net of unearned income		456,520		378,335
Recorded investment greater than 90 days and accruing		0		0
Non-Covered Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days		6,567	[2]	11,537
Past due, 60-89 days		2,201	[2]	3,849
Past due, greater than 90 days		67,361	[2]	49,470
Total past due		76,129	[2]	64,856
Current		3,073,002		1,326,950
Discount (premium)		(64,911)		(64,020)
Non-covered loans, net of unearned income		3,084,220		1,327,786
Recorded investment greater than 90 days and accruing		63,972		47,603
Non-Covered Acquired Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income		2,132,008		591,498
Non-Covered Acquired Loans | Commercial Loans | Commercial Real Estate - Construction
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	0		2,740
Past due, 60-89 days	[2]	260		57
Past due, greater than 90 days	[2]	6,965		1,284
Total past due	[2]	7,225		4,081
Current		118,084		26,667
Discount (premium)		(1,548)		(1,170)
Non-covered loans, net of unearned income		123,761		29,578
Recorded investment greater than 90 days and accruing		6,965		1,284
Non-Covered Acquired Loans | Commercial Loans | Commercial Real Estate - Other
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	3,267		4,419
Past due, 60-89 days	[2]	25		840
Past due, greater than 90 days	[2]	40,206		26,480
Total past due	[2]	43,498		31,739
Current		1,487,123		473,644
Discount (premium)		(39,944)		(39,119)
Non-covered loans, net of unearned income		1,490,677		466,264
Recorded investment greater than 90 days and accruing		39,066		26,376
Non-Covered Acquired Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	1,464		2,106
Past due, 60-89 days	[2]	346		70
Past due, greater than 90 days	[2]	6,566		1,624
Total past due	[2]	8,376		3,800
Current		508,047		89,338
Discount (premium)		(4,374)		(5,224)
Non-covered loans, net of unearned income		512,049		87,914
Recorded investment greater than 90 days and accruing		5,882		1,635
Non-Covered Acquired Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	95		0
Past due, 60-89 days	[2]	382		0
Past due, greater than 90 days	[2]	1,392		11
Total past due	[2]	1,869		11
Current		3,652		7,731
Discount (premium)		0		0
Non-covered loans, net of unearned income		5,521		7,742
Recorded investment greater than 90 days and accruing		1,392		0
Non-Covered Acquired Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income		409,472		424,579
Non-Covered Acquired Loans | Residential Mortgage Loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	85		152
Past due, 60-89 days	[2]	846		2,367
Past due, greater than 90 days	[2]	5,470		9,339
Total past due	[2]	6,401		11,858
Current		407,673		418,552
Discount (premium)		(4,602)		(5,831)
Non-covered loans, net of unearned income		409,472		424,579
Recorded investment greater than 90 days and accruing		4,430		8,087
Non-Covered Acquired Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income		542,740		311,709
Non-Covered Acquired Loans | Consumer and Other Loans | Consumer - Home Equity
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	1,063		649
Past due, 60-89 days	[2]	221		385
Past due, greater than 90 days	[2]	6,097		8,774
Total past due	[2]	7,381		9,808
Current		452,928		216,310
Discount (premium)		(10,644)		(8,419)
Non-covered loans, net of unearned income		449,665		217,699
Recorded investment greater than 90 days and accruing		5,643		8,383
Non-Covered Acquired Loans | Consumer and Other Loans | Consumer - Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	0		13
Past due, 60-89 days	[2]	5		17
Past due, greater than 90 days	[2]	19		9
Total past due	[2]	24		39
Current		142		393
Discount (premium)		(39)		(40)
Non-covered loans, net of unearned income		127		392
Recorded investment greater than 90 days and accruing		19		9
Non-Covered Acquired Loans | Consumer and Other Loans | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Past due, 30-59 days	[2]	593		1,458
Past due, 60-89 days	[2]	116		113
Past due, greater than 90 days	[2]	646		1,949
Total past due	[2]	1,355		3,520
Current		95,353		94,315
Discount (premium)		(3,760)		(4,217)
Non-covered loans, net of unearned income		92,948		93,618
Recorded investment greater than 90 days and accruing		$ 575		$ 1,829
[1]	Past due loans greater than 90 days days include all loans on non-accrual status, regardless of past due status, as of the period indicated. Non-accrual loans are presented separately in the “Non-accrual Loans” section below.
[2]	Past due information presents acquired loans at the gross loan balance, prior to application of discounts.

Loans - Schedule of Legacy Loan

Loans - Schedule of Legacy Loans on Nonaccrual Status (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	$ 51,274	$ 34,970
Commercial Loans | Commercial Real Estate - Construction
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	180	69
Commercial Loans | Commercial Real Estate - Other
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	14,299	6,859
Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	10,776	3,025
Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	3,478	27
Residential Mortgage Loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	14,879	14,362
Consumer and Other Loans | Consumer - Home Equity
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	5,278	7,404
Consumer and Other Loans | Consumer - Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	1,129	1,419
Consumer and Other Loans | Consumer - Credit Card
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	335	1,032
Consumer and Other Loans | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Total loans on nonaccrual status	$ 920	$ 773

Loans - Schedule of Carrying Am

Loans - Schedule of Carrying Amount of Acquired Covered Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014		Sep. 30, 2014
Accounts, Notes, Loans and Financing Receivable
Total covered loans	$ 253,541	$ 444,544
Covered Loans
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	52,301	37,532
Acquired performing loans	201,240	407,012
Total covered loans	253,541	444,544	[1]	$ 524,189
Covered Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	19,143	1,253
Acquired performing loans	35,866	219,133
Total covered loans	55,009	220,386	[1]
Covered Loans | Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	18,576	1,253
Acquired performing loans	25,014	187,873
Total covered loans	43,590	189,126	[1]	247,156
Covered Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	567	0
Acquired performing loans	10,852	31,260
Total covered loans	11,419	31,260	[1]	34,234
Covered Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	25,100	22,918
Acquired performing loans	94,826	105,106
Total covered loans	119,926	128,024	[1]	130,976
Covered Loans | Residential Mortgage Loans | Residential 1-4 Family
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	25,100	22,918
Acquired performing loans	94,826	105,106
Total covered loans	119,926	128,024	[1]
Covered Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	8,058	13,361
Acquired performing loans	70,548	82,773
Total covered loans	78,606	96,134	[1]	$ 111,823
Covered Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	8,038	12,872
Acquired performing loans	69,188	79,558
Total covered loans	77,226	92,430	[1]
Covered Loans | Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Acquired impaired loans	20	489
Acquired performing loans	1,360	3,215
Total covered loans	$ 1,380	$ 3,704	[1]
[1]	Included as covered loans at December 31, 2014 is $174.7 million of assets whose reimbursable loss periods ended as of January 1, 2015.

Loans - Schedule of Carrying 57

Loans - Schedule of Carrying Amount of Loans Acquired under ASC Topic 310-10 (Detail) - ASC Topic 310-30 - Florida Bank Group, Inc., Old Florida Bancshares, Inc., Georgia Commerce Bancshares, Inc. $ in Thousands	Sep. 30, 2015USD ($)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period
Contractually required principal and interest at acquisition	$ 2,402,890
Expected losses and foregone interest	(18,979)
Cash flows expected to be collected at acquisition	2,383,911
Fair value of acquired loans at acquisition	$ 2,130,276

Loans - Schedule of Carrying 58

Loans - Schedule of Carrying Amount of Loans Acquired (Detail) - Florida Bank Group, Inc., Old Florida Bancshares, Inc., Georgia Commerce Bancshares, Inc. - Receivables Acquired With Deteriorated Credit Quality $ in Thousands	Sep. 30, 2015USD ($)
Accounts, Notes, Loans and Financing Receivable
Contractually required principal and interest at acquisition	$ 53,532
Non-accretable difference (expected losses and foregone interest)	(7,852)
Cash flows expected to be collected at acquisition	45,680
Accretable yield	(4,592)
Basis in acquired loans at acquisition	41,088
Acquired Impaired Loans
Accounts, Notes, Loans and Financing Receivable
Contractually required principal and interest at acquisition	53,532
Non-accretable difference (expected losses and foregone interest)	(7,852)
Cash flows expected to be collected at acquisition	45,680
Accretable yield	(4,592)
Basis in acquired loans at acquisition	41,088
Acquired Performing Impaired Loans
Accounts, Notes, Loans and Financing Receivable
Contractually required principal and interest at acquisition	0
Non-accretable difference (expected losses and foregone interest)	0
Cash flows expected to be collected at acquisition	0
Accretable yield	0
Basis in acquired loans at acquisition	$ 0

Loans - Summary of Changes in A

Loans - Summary of Changes in Accretable Yields of Acquired Loans (Detail) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period		$ 287,651	$ 354,892
Acquisition		4,592	9,778
Transfers from non-accretable difference to accretable yield		7,199	17,824
Accretion		(60,305)	(79,356)
Changes in expected cash flows not affecting nonaccretable differences	[1]	(1,511)	(26,250)
Balance at end of period		237,626	276,888
Acquired Impaired Loans
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period		74,249	78,349
Acquisition		4,592	8,242
Transfers from non-accretable difference to accretable yield		70	3,952
Accretion		(9,774)	(12,766)
Changes in expected cash flows not affecting nonaccretable differences	[1]	1,209	(6,873)
Balance at end of period		70,346	70,904
Acquired Performing Impaired Loans
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period		213,402	276,543
Acquisition		0	1,536
Transfers from non-accretable difference to accretable yield		7,129	13,872
Accretion		(50,531)	(66,590)
Changes in expected cash flows not affecting nonaccretable differences	[1]	(2,720)	(19,377)
Balance at end of period		$ 167,280	$ 205,984
[1]	Includes changes in cash flows expected to be collected due to the impact of changes in actual or expected timing of liquidation events, modifications, changes in interest rates and changes in prepayment assumptions.

Loans - Schedule of Modified TD

Loans - Schedule of Modified TDRs (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Receivables [Abstract]
Extended maturities	$ 15,932
Maturity and interest rate adjustment	23,552
Forbearance	1,228
Other concession(s)	7,887	[1]
Total	$ 48,599
[1]	Other concessions include concessions or a combination of concessions that do not consist of maturity extensions, interest rate adjustments, forbearance or covenant modifications.

Loans - Schedule of Subsequentl

Loans - Schedule of Subsequently Defaulted TDRs (Detail) - TDRs Occurring During The Period - Non-Covered TDRs $ in Thousands		9 Months Ended
		Sep. 30, 2015USD ($)SecurityLoan	Sep. 30, 2014USD ($)SecurityLoan
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan		27
Pre-modification outstanding recorded investment		$ 49,640
Post-modification outstanding recorded investment	[1]	$ 48,599
Number of loans | SecurityLoan		20	43
Recorded investment		$ 29,468	$ 1,825
Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan		8
Pre-modification outstanding recorded investment		$ 26,408
Post-modification outstanding recorded investment	[1]	$ 25,572
Number of loans | SecurityLoan		4	31
Recorded investment		$ 12,939	$ 58
Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan		18
Pre-modification outstanding recorded investment		$ 19,798
Post-modification outstanding recorded investment	[1]	$ 19,643
Number of loans | SecurityLoan		15	11
Recorded investment		$ 13,145	$ 1,767
Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan		1
Pre-modification outstanding recorded investment		$ 3,434
Post-modification outstanding recorded investment	[1]	$ 3,384
Number of loans | SecurityLoan		1	0
Recorded investment		$ 3,384	$ 0
Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan		0	0
Recorded investment		$ 0	$ 0
Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan		0	1
Recorded investment		$ 0	$ 0
[1]	Recorded investment includes any allowance for credit losses recorded on the TDRs at the dates indicated.

Allowance for Credit Losses a62

Allowance for Credit Losses and Credit Quality - Schedule of Allowance for Loan Losses for Covered Loan and Non-Covered Loan Portfolios (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period			$ 130,131	$ 143,074
Provision for loan losses before benefit attributable to FDIC loss share agreements			17,855	13,718
Adjustment attributable to FDIC loss share arrangements			(1,342)	1,153
Provision for loan losses	$ 5,062	$ 5,714	19,197	12,565
Transfer of balance to OREO			(566)	(5,378)
Transfer of balance to non-covered			0
Loans charged-off			(22,234)	(21,651)
Recoveries			5,068	4,777
Allowance for loans losses at end of period	130,254	134,540	130,254	134,540
Financing Receivable, Allowance For Credit Losses, Unfunded Commitments [Roll Forward]
Reserve for unfunded commitments at beginning of period			11,801	11,147
Provision for unfunded lending commitments			2,724	952
Reserve for unfunded commitments at end of period	14,525	12,099	14,525	12,099
Allowance for credit losses at end of period	144,779	146,639	144,779	146,639
Non-Covered Legacy Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period			76,174	67,342
Provision for loan losses before benefit attributable to FDIC loss share agreements			17,743	9,635
Adjustment attributable to FDIC loss share arrangements			0	0
Provision for loan losses			17,743	9,635
Transfer of balance to OREO			0	0
Transfer of balance to non-covered			0
Loans charged-off			(12,073)	(8,242)
Recoveries			4,556	4,338
Allowance for loans losses at end of period	86,400	73,073	86,400	73,073
Financing Receivable, Allowance For Credit Losses, Unfunded Commitments [Roll Forward]
Reserve for unfunded commitments at beginning of period			11,801	11,147
Provision for unfunded lending commitments			2,724	952
Reserve for unfunded commitments at end of period	14,525	12,099	14,525	12,099
Allowance for credit losses at end of period	100,925	85,172	100,925	85,172
Non-Covered Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period			9,193	4,557
Provision for loan losses before benefit attributable to FDIC loss share agreements			143	(1,795)
Adjustment attributable to FDIC loss share arrangements			0	0
Provision for loan losses			143	(1,795)
Transfer of balance to OREO			(209)	(207)
Transfer of balance to non-covered			28,700
Loans charged-off			(8,973)	(586)
Recoveries			504	401
Allowance for loans losses at end of period	29,358	2,370	29,358	2,370
Financing Receivable, Allowance For Credit Losses, Unfunded Commitments [Roll Forward]
Reserve for unfunded commitments at beginning of period			0	0
Provision for unfunded lending commitments			0	0
Reserve for unfunded commitments at end of period	0	0	0	0
Allowance for credit losses at end of period	29,358	2,370	29,358	2,370
Covered Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period			44,764	71,175
Provision for loan losses before benefit attributable to FDIC loss share agreements			(31)	5,878
Adjustment attributable to FDIC loss share arrangements			(1,342)	1,153
Provision for loan losses			1,311	4,725
Transfer of balance to OREO			(357)	(5,171)
Transfer of balance to non-covered			(28,700)
Loans charged-off			(1,188)	(12,823)
Recoveries			8	38
Allowance for loans losses at end of period	14,496	59,097	14,496	59,097
Financing Receivable, Allowance For Credit Losses, Unfunded Commitments [Roll Forward]
Reserve for unfunded commitments at beginning of period			0	0
Provision for unfunded lending commitments			0	0
Reserve for unfunded commitments at end of period	0	0	0	0
Allowance for credit losses at end of period	$ 14,496	$ 59,097	$ 14,496	$ 59,097

Allowance for Credit Losses a63

Allowance for Credit Losses and Credit Quality - Schedule of Allowance for Loan Losses by Loan Portfolio (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	$ 130,131	$ 143,074
Transfer of balance to OREO	(566)	(5,378)
Transfer of balance to non-covered	0
Loans charged off	(22,234)	(21,651)
Recoveries	5,068	4,777
Allowance for loans losses at end of period	130,254	134,540
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	11,801	11,147
Reserve for unfunded commitments at end of period	14,525	12,099
Allowance for credit losses at end of period	144,779	146,639
Loans, net of unearned income:
Total covered loans	253,541		$ 444,544
Non-Covered Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	85,367	71,899
(Reversal of) Provision for loan losses	17,886	7,840
Transfer of balance to OREO	(209)	(207)
Transfer of balance to non-covered	28,700
Loans charged off	(21,046)	(8,828)
Recoveries	5,060	4,739
Allowance for loans losses at end of period	115,758	75,443
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	11,801	11,147
(Reversal of) Provision for unfunded commitments	2,724	952
Reserve for unfunded commitments at end of period	14,525	12,099
Allowance for credit losses at end of period	130,283	87,542
Allowance on loans individually evaluated for impairment	1,716	25
Allowance on loans collectively evaluated for impairment	128,567	87,517
Balance at end of period	13,863,478	10,556,698
Loans, net of unearned income:
Balance at end of period individually evaluated for impairment	52,744	11,339
Balance at end of period collectively evaluated for impairment	13,744,595	10,525,869
Balance at end of period acquired with deteriorated credit quality	66,139	19,490
Non-Covered Loans | Commercial Loans | Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	32,630	26,126
(Reversal of) Provision for loan losses	(356)	630
Transfer of balance to OREO	174	0
Transfer of balance to non-covered	20,763
Loans charged off	(7,091)	(1,214)
Recoveries	1,543	2,209
Allowance for loans losses at end of period	47,663	27,751
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	3,370	3,071
(Reversal of) Provision for unfunded commitments	218	671
Reserve for unfunded commitments at end of period	3,588	3,742
Allowance for credit losses at end of period	51,251	31,493
Allowance on loans individually evaluated for impairment	883	25
Allowance on loans collectively evaluated for impairment	50,368	31,468
Balance at end of period	5,936,161	3,988,172
Loans, net of unearned income:
Balance at end of period individually evaluated for impairment	27,299	7,357
Balance at end of period collectively evaluated for impairment	5,874,262	3,965,754
Balance at end of period acquired with deteriorated credit quality	34,600	15,061
Non-Covered Loans | Commercial Loans | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	26,486	22,101
(Reversal of) Provision for loan losses	1,327	3,283
Transfer of balance to OREO	(169)	(130)
Transfer of balance to non-covered	1,445
Loans charged off	(1,162)	(1,097)
Recoveries	164	93
Allowance for loans losses at end of period	28,091	24,250
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	3,733	1,814
(Reversal of) Provision for unfunded commitments	(149)	1,674
Reserve for unfunded commitments at end of period	3,584	3,488
Allowance for credit losses at end of period	31,675	27,738
Allowance on loans individually evaluated for impairment	817	0
Allowance on loans collectively evaluated for impairment	30,858	27,738
Balance at end of period	3,291,552	2,398,010
Loans, net of unearned income:
Balance at end of period individually evaluated for impairment	25,231	3,276
Balance at end of period collectively evaluated for impairment	3,255,580	2,392,172
Balance at end of period acquired with deteriorated credit quality	10,741	2,562
Non-Covered Loans | Commercial Loans | Energy-Related
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	5,999	6,878
(Reversal of) Provision for loan losses	9,339	(1,115)
Transfer of balance to OREO	0	0
Transfer of balance to non-covered	0
Loans charged off	(3)	0
Recoveries	0	0
Allowance for loans losses at end of period	15,335	5,763
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	1,596	3,043
(Reversal of) Provision for unfunded commitments	2,037	(1,427)
Reserve for unfunded commitments at end of period	3,633	1,616
Allowance for credit losses at end of period	18,968	7,379
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	18,968	7,379
Balance at end of period	719,456	839,823
Loans, net of unearned income:
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	719,456	839,823
Balance at end of period acquired with deteriorated credit quality	0	0
Non-Covered Loans | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	2,875	2,546
(Reversal of) Provision for loan losses	1,897	514
Transfer of balance to OREO	(143)	(12)
Transfer of balance to non-covered	0
Loans charged off	(283)	(607)
Recoveries	48	134
Allowance for loans losses at end of period	4,394	2,575
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	168	72
(Reversal of) Provision for unfunded commitments	650	11
Reserve for unfunded commitments at end of period	818	83
Allowance for credit losses at end of period	5,212	2,658
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	5,212	2,658
Balance at end of period	1,070,015	931,803
Loans, net of unearned income:
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	1,056,797	931,643
Balance at end of period acquired with deteriorated credit quality	13,218	160
Non-Covered Loans | Consumer and Other Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	17,377	14,248
(Reversal of) Provision for loan losses	5,679	4,528
Transfer of balance to OREO	(71)	(65)
Transfer of balance to non-covered	6,492
Loans charged off	(12,507)	(5,910)
Recoveries	3,305	2,303
Allowance for loans losses at end of period	20,275	15,104
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	2,934	3,147
(Reversal of) Provision for unfunded commitments	(32)	23
Reserve for unfunded commitments at end of period	2,902	3,170
Allowance for credit losses at end of period	23,177	18,274
Allowance on loans individually evaluated for impairment	16	0
Allowance on loans collectively evaluated for impairment	23,161	18,274
Balance at end of period	2,846,294	2,398,890
Loans, net of unearned income:
Balance at end of period individually evaluated for impairment	214	706
Balance at end of period collectively evaluated for impairment	2,838,500	2,396,477
Balance at end of period acquired with deteriorated credit quality	7,580	1,707
Covered Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	44,764	71,175
(Reversal of) Provision for loan losses	1,311	4,725
(Decrease) Increase in FDIC loss share receivable	(1,342)	1,153
Transfer of balance to OREO	(357)	(5,171)
Transfer of balance to non-covered	(28,700)
Loans charged off	(1,188)	(12,823)
Recoveries	8	38
Allowance for loans losses at end of period	14,496	59,097
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	0	0
Reserve for unfunded commitments at end of period	0	0
Allowance for credit losses at end of period	14,496	59,097
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	14,496	59,097
Loans, net of unearned income:
Total covered loans	253,541	524,189	444,544	[1]
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	201,240	477,888
Balance at end of period acquired with deteriorated credit quality	52,301	46,301
Covered Loans | Commercial Loans
Loans, net of unearned income:
Total covered loans	55,009		220,386	[1]
Covered Loans | Commercial Loans | Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	24,072	38,772
(Reversal of) Provision for loan losses	217	2,544
(Decrease) Increase in FDIC loss share receivable	748	734
Transfer of balance to OREO	0	(1,874)
Transfer of balance to non-covered	(20,763)
Loans charged off	(1,188)	(9,578)
Recoveries	0	38
Allowance for loans losses at end of period	3,086	30,636
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	3,086	30,636
Loans, net of unearned income:
Total covered loans	43,590	247,156	189,126	[1]
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	25,014	242,478
Balance at end of period acquired with deteriorated credit quality	18,576	4,678
Covered Loans | Commercial Loans | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	1,235	5,380
(Reversal of) Provision for loan losses	152	376
(Decrease) Increase in FDIC loss share receivable	59	609
Transfer of balance to OREO	(1)	(1,162)
Transfer of balance to non-covered	(1,445)
Loans charged off	0	(2,192)
Recoveries	0	0
Allowance for loans losses at end of period	0	3,011
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	0	3,011
Loans, net of unearned income:
Total covered loans	11,419	34,234	31,260	[1]
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	10,852	33,614
Balance at end of period acquired with deteriorated credit quality	567	620
Covered Loans | Commercial Loans | Energy-Related
Loans, net of unearned income:
Total covered loans	0		0	[1]
Covered Loans | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	6,286	10,889
(Reversal of) Provision for loan losses	841	971
(Decrease) Increase in FDIC loss share receivable	(277)	(2,911)
Transfer of balance to OREO	(339)	(648)
Transfer of balance to non-covered	0
Loans charged off	0	(90)
Recoveries	8	0
Allowance for loans losses at end of period	6,519	8,211
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	6,519	8,211
Loans, net of unearned income:
Total covered loans	119,926	130,976	128,024	[1]
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	94,826	106,672
Balance at end of period acquired with deteriorated credit quality	25,100	24,304
Covered Loans | Consumer and Other Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loans losses at beginning of period	13,171	16,134
(Reversal of) Provision for loan losses	101	834
(Decrease) Increase in FDIC loss share receivable	(1,872)	2,721
Transfer of balance to OREO	(17)	(1,487)
Transfer of balance to non-covered	(6,492)
Loans charged off	0	(963)
Recoveries	0	0
Allowance for loans losses at end of period	4,891	17,239
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	4,891	17,239
Loans, net of unearned income:
Total covered loans	78,606	111,823	$ 96,134	[1]
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	70,548	95,124
Balance at end of period acquired with deteriorated credit quality	$ 8,058	$ 16,699
[1]	Included as covered loans at December 31, 2014 is $174.7 million of assets whose reimbursable loss periods ended as of January 1, 2015.

Allowance for Credit Losses a64

Allowance for Credit Losses and Credit Quality - Investment in Covered Loans and Non-Covered Loans by Credit Quality Indicator (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014		Sep. 30, 2014
Non-covered Acquired Loans [Abstract]
Non-covered loans, net of unearned income	$ 13,863,478	$ 10,996,500
Total covered loans	253,541	444,544
Non-Covered Legacy Loans
Non-covered Acquired Loans [Abstract]
Current	10,710,746	9,603,423
Non-covered loans, net of unearned income	10,779,258	9,668,714
Non-Covered Acquired Loans
Non-covered Acquired Loans [Abstract]
Current	3,073,002	1,326,950
Non-covered loans, net of unearned income	3,084,220	1,327,786
Covered Loans
Non-covered Acquired Loans [Abstract]
Total covered loans	253,541	444,544	[1]	$ 524,189
Commercial Loans | Non-Covered Legacy Loans
Non-covered Legacy Loans
Total	7,815,161	7,002,198
Non-covered Acquired Loans [Abstract]
Non-covered loans, net of unearned income	7,815,161	7,002,198
Commercial Loans | Non-Covered Legacy Loans | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	7,645,964	6,891,435
Commercial Loans | Non-Covered Legacy Loans | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	59,221	57,417
Commercial Loans | Non-Covered Legacy Loans | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	108,723	51,251
Commercial Loans | Non-Covered Legacy Loans | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,033	2,095
Commercial Loans | Non-Covered Legacy Loans | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	220
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Construction
Non-covered Legacy Loans
Total	559,208	484,239
Non-covered Acquired Loans [Abstract]
Current	559,028	483,663
Non-covered loans, net of unearned income	559,208	484,239
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Construction | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	557,603	483,930
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Construction | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	100	240
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Construction | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,503	69
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Construction | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0	0
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Construction | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	2
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Other
Non-covered Legacy Loans
Total	3,762,515	3,192,572
Non-covered Acquired Loans [Abstract]
Current	3,744,986	3,173,766
Non-covered loans, net of unearned income	3,762,515	3,192,572
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Other | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	3,699,714	3,120,370
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Other | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	24,473	49,847
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Other | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	37,874	22,193
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Other | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	454	162
Commercial Loans | Non-Covered Legacy Loans | Commercial Real Estate - Other | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0
Commercial Loans | Non-Covered Legacy Loans | Commercial and Industrial
Non-covered Legacy Loans
Total	2,779,503	2,452,521
Non-covered Acquired Loans [Abstract]
Current	2,766,605	2,445,847
Non-covered loans, net of unearned income	2,779,503	2,452,521
Commercial Loans | Non-Covered Legacy Loans | Commercial and Industrial | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	2,732,122	2,414,293
Commercial Loans | Non-Covered Legacy Loans | Commercial and Industrial | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	18,821	7,330
Commercial Loans | Non-Covered Legacy Loans | Commercial and Industrial | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	27,763	28,965
Commercial Loans | Non-Covered Legacy Loans | Commercial and Industrial | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	579	1,933
Commercial Loans | Non-Covered Legacy Loans | Commercial and Industrial | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	218
Commercial Loans | Non-Covered Legacy Loans | Energy-Related
Non-covered Legacy Loans
Total	713,935	872,866
Non-covered Acquired Loans [Abstract]
Current	710,457	872,839
Non-covered loans, net of unearned income	713,935	872,866
Commercial Loans | Non-Covered Legacy Loans | Energy-Related | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	656,525	872,842
Commercial Loans | Non-Covered Legacy Loans | Energy-Related | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	15,827	0
Commercial Loans | Non-Covered Legacy Loans | Energy-Related | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	41,583	24
Commercial Loans | Non-Covered Legacy Loans | Energy-Related | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0	0
Commercial Loans | Non-Covered Legacy Loans | Energy-Related | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0
Commercial Loans | Non-Covered Acquired Loans
Non-covered Acquired Loans [Abstract]
Non-covered loans, net of unearned income	2,132,008	591,498
Commercial Loans | Non-Covered Acquired Loans | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	2,051,188	561,512
Commercial Loans | Non-Covered Acquired Loans | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	29,089	16,661
Commercial Loans | Non-Covered Acquired Loans | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	91,919	58,581
Commercial Loans | Non-Covered Acquired Loans | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	5,139	257
Commercial Loans | Non-Covered Acquired Loans | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	539
Commercial Loans | Non-Covered Acquired Loans | Discount
Non-covered Acquired Loans [Abstract]
Premium (discount)	(45,866)	(45,513)
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Construction
Non-covered Acquired Loans [Abstract]
Current	118,084	26,667
Non-covered loans, net of unearned income	123,761	29,578
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Construction | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	114,684	24,118
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Construction | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,226	2,006
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Construction | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	8,538	4,624
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Construction | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	861	0
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Construction | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Construction | Discount
Non-covered Acquired Loans [Abstract]
Premium (discount)	(1,548)	(1,170)
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Other
Non-covered Acquired Loans [Abstract]
Current	1,487,123	473,644
Non-covered loans, net of unearned income	1,490,677	466,264
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Other | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,434,860	443,450
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Other | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	23,421	12,794
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Other | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	69,084	49,139
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Other | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	3,256	0
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Other | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0
Commercial Loans | Non-Covered Acquired Loans | Commercial Real Estate - Other | Discount
Non-covered Acquired Loans [Abstract]
Premium (discount)	(39,944)	(39,119)
Commercial Loans | Non-Covered Acquired Loans | Commercial and Industrial
Non-covered Acquired Loans [Abstract]
Current	508,047	89,338
Non-covered loans, net of unearned income	512,049	87,914
Commercial Loans | Non-Covered Acquired Loans | Commercial and Industrial | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	498,286	86,213
Commercial Loans | Non-Covered Acquired Loans | Commercial and Industrial | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	3,671	1,861
Commercial Loans | Non-Covered Acquired Loans | Commercial and Industrial | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	12,905	4,807
Commercial Loans | Non-Covered Acquired Loans | Commercial and Industrial | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,022	257
Commercial Loans | Non-Covered Acquired Loans | Commercial and Industrial | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	539
Commercial Loans | Non-Covered Acquired Loans | Commercial and Industrial | Discount
Non-covered Acquired Loans [Abstract]
Premium (discount)	(4,374)	(5,224)
Commercial Loans | Non-Covered Acquired Loans | Energy-Related
Non-covered Acquired Loans [Abstract]
Current	3,652	7,731
Non-covered loans, net of unearned income	5,521	7,742
Commercial Loans | Non-Covered Acquired Loans | Energy-Related | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	3,358	7,731
Commercial Loans | Non-Covered Acquired Loans | Energy-Related | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	771	0
Commercial Loans | Non-Covered Acquired Loans | Energy-Related | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,392	11
Commercial Loans | Non-Covered Acquired Loans | Energy-Related | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0	0
Commercial Loans | Non-Covered Acquired Loans | Energy-Related | Loss
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	0
Commercial Loans | Non-Covered Acquired Loans | Energy-Related | Discount
Non-covered Acquired Loans [Abstract]
Premium (discount)	0	0
Commercial Loans | Covered Loans
Non-covered Acquired Loans [Abstract]
Total covered loans	68,899	236,900
Discount	13,890	16,514
Total covered loans	55,009	220,386	[1]
Commercial Loans | Covered Loans | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	31,570	145,620
Commercial Loans | Covered Loans | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	3,552	22,745
Commercial Loans | Covered Loans | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	29,574	68,535
Commercial Loans | Covered Loans | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	4,203	0
Commercial Loans | Covered Loans | Commercial Real Estate - Construction
Non-covered Acquired Loans [Abstract]
Total covered loans	2,047	44,667
Commercial Loans | Covered Loans | Commercial Real Estate - Construction | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	113	34,731
Commercial Loans | Covered Loans | Commercial Real Estate - Construction | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	820	1,928
Commercial Loans | Covered Loans | Commercial Real Estate - Construction | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	23	8,008
Commercial Loans | Covered Loans | Commercial Real Estate - Construction | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,091	0
Commercial Loans | Covered Loans | Commercial Real Estate - Other
Non-covered Acquired Loans [Abstract]
Total covered loans	51,201	159,183
Commercial Loans | Covered Loans | Commercial Real Estate - Other | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	25,820	87,509
Commercial Loans | Covered Loans | Commercial Real Estate - Other | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	1,922	20,422
Commercial Loans | Covered Loans | Commercial Real Estate - Other | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	22,705	51,252
Commercial Loans | Covered Loans | Commercial Real Estate - Other | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	754	0
Commercial Loans | Covered Loans | Commercial and Industrial
Non-covered Acquired Loans [Abstract]
Total covered loans	15,651	33,050
Total covered loans	11,419	31,260	[1]	34,234
Commercial Loans | Covered Loans | Commercial and Industrial | Pass
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	5,637	23,380
Commercial Loans | Covered Loans | Commercial and Industrial | Special Mention
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	810	395
Commercial Loans | Covered Loans | Commercial and Industrial | Substandard
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	6,846	9,275
Commercial Loans | Covered Loans | Commercial and Industrial | Doubtful
Non-covered Legacy Loans
Credit quality indicator by asset risk classification	2,358	0
Commercial Loans | Covered Loans | Energy-Related
Non-covered Acquired Loans [Abstract]
Total covered loans	0	0	[1]
Residential and Consumer Portfolio Segment | Non-Covered Legacy Loans
Non-covered Legacy Loans
Current	2,929,670	2,627,308
30+ Days Past Due	34,427	39,208
Total	2,964,097	2,666,516
Residential and Consumer Portfolio Segment | Non-Covered Acquired Loans
Non-covered Acquired Loans [Abstract]
Current	956,096	729,570
30+ Days Past Due	15,161	25,225
Premium (discount)	(19,045)	(18,507)
Non-covered loans, net of unearned income	952,212	736,288
Residential and Consumer Portfolio Segment | Covered Loans
Non-covered Acquired Loans [Abstract]
Current	215,334	241,057
30+ Days Past Due	30,357	38,652
Premium (discount)	(47,159)	(55,551)
Total covered loans	198,532	224,158
Residential Mortgage | Non-Covered Legacy Loans
Non-covered Acquired Loans [Abstract]
Non-covered loans, net of unearned income	660,543	527,694
Residential Mortgage | Non-Covered Legacy Loans | Residential Mortgage
Non-covered Legacy Loans
Current	640,927	508,789
30+ Days Past Due	19,616	18,905
Total	660,543	527,694
Non-covered Acquired Loans [Abstract]
Current	640,927	508,789
Non-covered loans, net of unearned income	660,543	527,694
Residential Mortgage | Non-Covered Acquired Loans
Non-covered Acquired Loans [Abstract]
Non-covered loans, net of unearned income	409,472	424,579
Residential Mortgage | Non-Covered Acquired Loans | Residential Mortgage
Non-covered Acquired Loans [Abstract]
Current	407,673	418,552
30+ Days Past Due	6,401	11,858
Premium (discount)	(4,602)	(5,831)
Non-covered loans, net of unearned income	409,472	424,579
Residential Mortgage | Covered Loans
Non-covered Acquired Loans [Abstract]
Total covered loans	119,926	128,024	[1]	130,976
Residential Mortgage | Covered Loans | Residential Mortgage
Non-covered Acquired Loans [Abstract]
Current	128,804	140,628
30+ Days Past Due	20,672	22,058
Premium (discount)	(29,550)	(34,662)
Total covered loans	119,926	128,024
Consumer and Other Loans | Non-Covered Legacy Loans
Non-covered Acquired Loans [Abstract]
Non-covered loans, net of unearned income	2,303,554	2,138,822
Consumer and Other Loans | Non-Covered Legacy Loans | Consumer - Home Equity
Non-covered Legacy Loans
Current	1,480,368	1,278,865
30+ Days Past Due	8,428	12,111
Total	1,488,796	1,290,976
Non-covered Acquired Loans [Abstract]
Current	1,480,368	1,278,865
Non-covered loans, net of unearned income	1,488,796	1,290,976
Consumer and Other Loans | Non-Covered Legacy Loans | Consumer - Indirect Automobile
Non-covered Legacy Loans
Current	277,996	392,504
30+ Days Past Due	3,526	4,262
Total	281,522	396,766
Non-covered Acquired Loans [Abstract]
Current	277,996	392,504
Non-covered loans, net of unearned income	281,522	396,766
Consumer and Other Loans | Non-Covered Legacy Loans | Consumer - Credit Card
Non-covered Legacy Loans
Current	76,018	71,297
30+ Days Past Due	698	1,448
Total	76,716	72,745
Non-covered Acquired Loans [Abstract]
Current	76,018	71,297
Non-covered loans, net of unearned income	76,716	72,745
Consumer and Other Loans | Non-Covered Legacy Loans | Consumer - Other
Non-covered Legacy Loans
Current	454,361	375,853
30+ Days Past Due	2,159	2,482
Total	456,520	378,335
Non-covered Acquired Loans [Abstract]
Current	454,361	375,853
Non-covered loans, net of unearned income	456,520	378,335
Consumer and Other Loans | Non-Covered Acquired Loans
Non-covered Acquired Loans [Abstract]
Non-covered loans, net of unearned income	542,740	311,709
Consumer and Other Loans | Non-Covered Acquired Loans | Consumer - Home Equity
Non-covered Acquired Loans [Abstract]
Current	452,928	216,310
30+ Days Past Due	7,381	9,808
Premium (discount)	(10,644)	(8,419)
Non-covered loans, net of unearned income	449,665	217,699
Consumer and Other Loans | Non-Covered Acquired Loans | Consumer - Indirect Automobile
Non-covered Acquired Loans [Abstract]
Current	142	393
30+ Days Past Due	24	39
Premium (discount)	(39)	(40)
Non-covered loans, net of unearned income	127	392
Consumer and Other Loans | Non-Covered Acquired Loans | Consumer - Other
Non-covered Acquired Loans [Abstract]
Current	95,353	94,315
30+ Days Past Due	1,355	3,520
Premium (discount)	(3,760)	(4,217)
Non-covered loans, net of unearned income	92,948	93,618
Consumer and Other Loans | Covered Loans
Non-covered Acquired Loans [Abstract]
Total covered loans	78,606	96,134	[1]	$ 111,823
Consumer and Other Loans | Covered Loans | Consumer - Home Equity
Non-covered Acquired Loans [Abstract]
Current	85,772	99,478
30+ Days Past Due	9,643	16,542
Premium (discount)	(18,189)	(23,590)
Total covered loans	77,226	92,430	[1]
Consumer and Other Loans | Covered Loans | Consumer - Indirect Automobile
Non-covered Acquired Loans [Abstract]
Total covered loans	0	0	[1]
Consumer and Other Loans | Covered Loans | Consumer - Credit Card
Non-covered Acquired Loans [Abstract]
Current	542	614
30+ Days Past Due	27	34
Premium (discount)	0	0
Total covered loans	569	648
Consumer and Other Loans | Covered Loans | Consumer - Other
Non-covered Acquired Loans [Abstract]
Current	216	337
30+ Days Past Due	15	18
Premium (discount)	580	2,701
Total covered loans	$ 811	$ 3,056
[1]	Included as covered loans at December 31, 2014 is $174.7 million of assets whose reimbursable loss periods ended as of January 1, 2015.

Allowance for Credit Losses a65

Allowance for Credit Losses and Credit Quality - Schedule of Investment in Impaired Loan (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Financing Receivable, Impaired
Recorded investment	$ 74,630		$ 74,630		$ 36,560
Unpaid principal balance	76,479		76,479		37,327
Related allowance	(1,849)		(1,849)		(767)
Average recorded investment	77,030	$ 40,761	75,501	$ 41,026
Interest income recognized	327	22	933	379
Commercial Loans
Financing Receivable, Impaired
Recorded investment	52,016		52,016		11,443
Unpaid principal balance	53,724		53,724		11,876
Related allowance	(1,708)		(1,708)		(433)
Average recorded investment	53,351	12,522	51,078	13,648
Interest income recognized	324	17	929	168
Consumer and Other Loans
Financing Receivable, Impaired
Recorded investment	7,806		7,806		11,006
Unpaid principal balance	7,876		7,876		11,088
Related allowance	(70)		(70)		(82)
Average recorded investment	8,671	10,934	9,323	11,037
Interest income recognized	3	5	4	92
Residential Mortgage
Financing Receivable, Impaired
Recorded investment	14,808		14,808		14,111
Unpaid principal balance	14,879		14,879		14,363
Related allowance	(71)		(71)		(252)
Average recorded investment	15,008	17,305	15,100	16,341
Interest income recognized	0	0	0	119
With No Related Allowance Recorded | Commercial Loans | Real Estate
Financing Receivable, Impaired
Recorded investment	16,491		16,491		6,680
Unpaid principal balance	16,491		16,491		6,680
Related allowance	0		0		0
Average recorded investment	16,018	7,026	16,036	7,114
Interest income recognized	37	6	79	20
With No Related Allowance Recorded | Commercial Loans | Commercial and Industrial
Financing Receivable, Impaired
Recorded investment	20,360		20,360		2,483
Unpaid principal balance	20,360		20,360		2,483
Related allowance	0		0		0
Average recorded investment	20,055	3,553	20,630	4,417
Interest income recognized	159	11	465	48
With No Related Allowance Recorded | Commercial Loans | Energy-Related
Financing Receivable, Impaired
Recorded investment	3,384		3,384		0
Unpaid principal balance	3,384		3,384		0
Related allowance	0		0		0
Average recorded investment	3,409	0	3,425	0
Interest income recognized	0	0	0	0
With No Related Allowance Recorded | Consumer and Other Loans | Consumer - Home Equity
Financing Receivable, Impaired
Recorded investment	214		214		682
Unpaid principal balance	214		214		682
Related allowance	0		0		0
Average recorded investment	215	692	204	700
Interest income recognized	3	0	4	14
With An Allowance Recorded | Commercial Loans | Real Estate
Financing Receivable, Impaired
Recorded investment	10,681		10,681		1,044
Unpaid principal balance	11,566		11,566		1,069
Related allowance	(885)		(885)		(25)
Average recorded investment	11,649	1,631	8,247	1,533
Interest income recognized	128	0	385	91
With An Allowance Recorded | Commercial Loans | Commercial and Industrial
Financing Receivable, Impaired
Recorded investment	1,009		1,009		1,209
Unpaid principal balance	1,829		1,829		1,617
Related allowance	(820)		(820)		(408)
Average recorded investment	2,121	312	2,634	584
Interest income recognized	0	0	0	9
With An Allowance Recorded | Commercial Loans | Energy-Related
Financing Receivable, Impaired
Recorded investment	91		91		27
Unpaid principal balance	94		94		27
Related allowance	(3)		(3)		0
Average recorded investment	99	0	106	0
Interest income recognized	0	0	0	0
With An Allowance Recorded | Consumer and Other Loans | Consumer - Home Equity
Financing Receivable, Impaired
Recorded investment	5,248		5,248		7,121
Unpaid principal balance	5,278		5,278		7,165
Related allowance	(30)		(30)		(44)
Average recorded investment	5,344	7,177	5,462	7,404
Interest income recognized	0	5	0	40
With An Allowance Recorded | Consumer and Other Loans | Consumer - Indirect Automobile
Financing Receivable, Impaired
Recorded investment	1,120		1,120		1,410
Unpaid principal balance	1,129		1,129		1,419
Related allowance	(9)		(9)		(9)
Average recorded investment	1,361	1,544	1,551	1,720
Interest income recognized	0	0	0	27
With An Allowance Recorded | Consumer and Other Loans | Consumer - Credit Card
Financing Receivable, Impaired
Recorded investment	329		329		1,012
Unpaid principal balance	335		335		1,032
Related allowance	(6)		(6)		(20)
Average recorded investment	721	1,051	1,038	724
Interest income recognized	0	0	0	0
With An Allowance Recorded | Consumer and Other Loans | Consumer - Other
Financing Receivable, Impaired
Recorded investment	895		895		781
Unpaid principal balance	920		920		790
Related allowance	(25)		(25)		(9)
Average recorded investment	1,030	470	1,068	489
Interest income recognized	0	0	0	11
With An Allowance Recorded | Residential Mortgage | Residential Mortgage
Financing Receivable, Impaired
Recorded investment	14,808		14,808		14,111
Unpaid principal balance	14,879		14,879		14,363
Related allowance	(71)		(71)		$ (252)
Average recorded investment	15,008	17,305	15,100	16,341
Interest income recognized	$ 0	$ 0	$ 0	$ 119

Loss Sharing Agreements and F66

Loss Sharing Agreements and FDIC Loss Share Receivable (Detail) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2015USD ($)Businessacquisition	Sep. 30, 2014USD ($)	Dec. 31, 2021acquisition	Dec. 31, 2020acquisition	Dec. 31, 2019acquisition	Dec. 31, 2016acquisition	Dec. 31, 2015acquisition	Dec. 31, 2014USD ($)acquisition	Dec. 31, 2013USD ($)
Loss Sharing Agreements and FDIC Loss Share Receivable [Abstract]
Number of acquisitions | Business	6
Percentage of covered loan and foreclosed real estate losses	80.00%
Percentage of losses, that exceed contractual thresholds, that are covered	95.00%
Number of acquisitions exceeding loan loss contractual threshold	3
Loss Sharing Agreements and FDIC Loss Share Receivable [Line Items]
Recovery period for covered assets	3 years
FDIC loss share receivables | $	$ 43,443	$ 94,712						$ 69,627	$ 162,312
Impairment | $	$ 0	$ 5,097
Excluding Single Family
Loss Sharing Agreements and FDIC Loss Share Receivable [Line Items]
Number of acquisitions where FDIC loan loss reimbursable period is ending								3
Excluding Single Family | Forecast
Loss Sharing Agreements and FDIC Loss Share Receivable [Line Items]
Number of acquisitions where FDIC loan loss reimbursable period is ending						2	1
Single Family | Forecast
Loss Sharing Agreements and FDIC Loss Share Receivable [Line Items]
Number of acquisitions where FDIC loan loss reimbursable period is ending			2	1	3

Loss Sharing Agreements and F67

Loss Sharing Agreements and FDIC Loss Share Receivable - Schedule of FDIC Loss Share Receivables (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
FDIC Indemnification Asset [Roll Forward]
Balance at beginning of period			$ 69,627	$ 162,312
Change due to (reversal of) loan loss provision recorded on FDIC covered loans			(1,342)	1,153
Amortization	$ (5,600)	$ (25,120)	(19,011)	(61,393)
(Submission of reimbursable losses) recoveries payable to the FDIC			(4,084)	4,901
Impairment			0	(5,097)
Changes due to a change in cash flow assumptions on OREO and other changes			(1,747)	(7,164)
Balance at end of period	$ 43,443	$ 94,712	$ 43,443	$ 94,712

Goodwill and Other Intangible68

Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Title plant assets	$ 6.7	$ 6.7

Goodwill and Other Intangible69

Goodwill and Other Intangible Assets - Schedule of Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Beginning balance	$ 517,526	$ 401,872
Goodwill acquired during the period	201,937	115,654
Ending balance	719,463	517,526
Operating Segments | IBERIABANK
Goodwill [Roll Forward]
Beginning balance	489,183	373,905
Goodwill acquired during the period	201,937	115,278
Ending balance	691,120	489,183
Operating Segments | IMC
Goodwill [Roll Forward]
Beginning balance	23,178	23,178
Goodwill acquired during the period	0	0
Ending balance	23,178	23,178
Operating Segments | LTC
Goodwill [Roll Forward]
Beginning balance	5,165	4,789
Goodwill acquired during the period	0	376
Ending balance	$ 5,165	$ 5,165

Goodwill and Other Intangible70

Goodwill and Other Intangible Assets - Schedule of Mortgage Servicing Rights at Carrying Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets
Gross carrying amount	$ 79,594	$ 57,665
Accumulated amortization	(43,305)	(37,304)
Net carrying amount	36,289	20,361
Mortgage Servicing Rights
Acquired Finite-Lived Intangible Assets
Gross carrying amount	6,110	4,751
Accumulated amortization	(2,021)	(1,253)
Net carrying amount	$ 4,089	$ 3,498

Goodwill and Other Intangible71

Goodwill and Other Intangible Assets - Schedule of Definite-Lived Intangible Assets at Carrying Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets
Gross carrying amount	$ 79,594	$ 57,665
Accumulated amortization	(43,305)	(37,304)
Net carrying amount	36,289	20,361
Core Deposit Intangibles
Acquired Finite-Lived Intangible Assets
Gross carrying amount	77,941	55,949
Accumulated amortization	(42,195)	(36,354)
Net carrying amount	35,746	19,595
Customer Relationships Intangible Asset
Acquired Finite-Lived Intangible Assets
Gross carrying amount	1,348	1,348
Accumulated amortization	(946)	(822)
Net carrying amount	402	526
Non-Compete Agreements
Acquired Finite-Lived Intangible Assets
Gross carrying amount	100	163
Accumulated amortization	(67)	(82)
Net carrying amount	33	81
Other Intangible Assets
Acquired Finite-Lived Intangible Assets
Gross carrying amount	205	205
Accumulated amortization	(97)	(46)
Net carrying amount	$ 108	$ 159

Derivative Instruments and Ot72

Derivative Instruments and Other Hedging Activities - Schedule of Outstanding Derivative Instruments (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash as collateral for derivative transactions	$ 27,200	$ 11,500
Fair Value of Derivatives
Derivative assets	41,440	32,903
Derivative instruments	24,534	15,411
Derivative liabilities	38,147	31,354
Notional Amount of Derivatives
Derivative assets	987,189	823,180
Derivative liabilities	1,297,423	1,062,436
Designated as Hedging Instrument
Fair Value of Derivatives
Derivative assets	0	0
Derivative liabilities	575	0
Notional Amount of Derivatives
Derivative assets	0	0
Derivative liabilities	108,500	0
Designated as Hedging Instrument | Interest Rate Contracts
Fair Value of Derivatives
Derivative instruments	575	0
Notional Amount of Derivatives
Derivative assets	0	0
Derivative liabilities	108,500	0
Designated as Hedging Instrument | Interest Rate Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	0	0
Designated as Hedging Instrument | Interest Rate Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	575	0
Not Designated as Hedging Instruments
Fair Value of Derivatives
Derivative assets	41,440	32,903
Derivative instruments	37,572
Derivative liabilities		31,354
Notional Amount of Derivatives
Derivative assets	987,189	823,180
Derivative liabilities	1,188,923	1,062,436
Not Designated as Hedging Instruments | Interest Rate Contracts
Fair Value of Derivatives
Derivative instruments	23,959	15,411
Notional Amount of Derivatives
Derivative assets	565,820	444,703
Derivative liabilities	565,820	444,703
Not Designated as Hedging Instruments | Interest Rate Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	23,960	15,434
Not Designated as Hedging Instruments | Interest Rate Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	23,960	15,434
Not Designated as Hedging Instruments | Foreign Exchange Contracts
Notional Amount of Derivatives
Derivative assets	4,392	0
Derivative liabilities	4,370	0
Not Designated as Hedging Instruments | Foreign Exchange Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	4,369	0
Not Designated as Hedging Instruments | Foreign Exchange Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	4,369	0
Not Designated as Hedging Instruments | Forward Sales Contracts
Notional Amount of Derivatives
Derivative assets	55,412	15,897
Derivative liabilities	428,547	391,992
Not Designated as Hedging Instruments | Forward Sales Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	452	25
Not Designated as Hedging Instruments | Forward Sales Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	3,108	2,556
Not Designated as Hedging Instruments | Written and Purchased Options
Notional Amount of Derivatives
Derivative assets	361,565	362,580
Derivative liabilities	190,186	225,741
Not Designated as Hedging Instruments | Written and Purchased Options | Other Assets
Fair Value of Derivatives
Derivative assets	12,659	17,444
Not Designated as Hedging Instruments | Written and Purchased Options | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	$ 6,135	$ 13,364

Derivative Instruments and Ot73

Derivative Instruments and Other Hedging Activities - Reconciliation of Gross Amounts in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash as collateral for derivative transactions		$ 27,200	$ 11,500
Derivative assets
Derivative instruments		30,086	28,798
Gross amounts not offset in the Balance Sheet, derivatives		0	0
Gross amounts not offset in the Balance Sheet, collateral	[1]	0	0
Net		30,086	28,798
Derivative liabilities
Derivative instruments		24,534	15,411
Gross amounts not offset in the Balance Sheet, derivatives		0	0
Gross amounts not offset in the Balance Sheet, collateral	[1]	(15,212)	(3,735)
Net		9,322	11,676
Written and Purchased Options
Derivative assets
Derivative instruments		6,127	13,387
Gross amounts not offset in the Balance Sheet, derivatives		0	0
Gross amounts not offset in the Balance Sheet, collateral	[1]	0	0
Net		6,127	13,387
Designated as Hedging Instrument | Interest Rate Contracts
Derivative assets
Derivative instruments		0	0
Gross amounts not offset in the Balance Sheet, derivatives		0	0
Gross amounts not offset in the Balance Sheet, collateral	[1]	0	0
Net		0	0
Derivative liabilities
Derivative instruments		575	0
Gross amounts not offset in the Balance Sheet, derivatives		0	0
Gross amounts not offset in the Balance Sheet, collateral		(508)	0	[1]
Net		67	0
Not Designated as Hedging Instruments
Derivative liabilities
Derivative instruments		37,572
Not Designated as Hedging Instruments | Interest Rate Contracts
Derivative assets
Derivative instruments		23,959	15,411
Gross amounts not offset in the Balance Sheet, derivatives		0	0
Gross amounts not offset in the Balance Sheet, collateral	[1]	0	0
Net		23,959	15,411
Derivative liabilities
Derivative instruments		23,959	15,411
Gross amounts not offset in the Balance Sheet, derivatives		0	0
Gross amounts not offset in the Balance Sheet, collateral	[1]	(14,704)	(3,735)
Net		$ 9,255	$ 11,676
[1]	Consists of cash collateral recorded at cost, which approximates fair value, and investment securities.

Derivative Instruments and Ot74

Derivative Instruments and Other Hedging Activities - Effect of Derivatives on Consolidated Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss)
Gain (loss) on derivatives, net	$ (5,920)	$ (2,469)	$ 2,884		$ (3,140)
Not Designated as Hedging Instruments | Interest Rate Contracts | Other Income
Derivative Instruments, Gain (Loss)
Gain (loss) on derivatives, net	1,130	406	3,069		1,971
Not Designated as Hedging Instruments | Forward Sales Contracts | Mortgage Income
Derivative Instruments, Gain (Loss)
Gain (loss) on derivatives, net	(6,524)	(3,648)	1,526		(7,512)
Not Designated as Hedging Instruments | Written and Purchased Options | Mortgage Income
Derivative Instruments, Gain (Loss)
Gain (loss) on derivatives, net	(526)	773	(1,711)		$ 2,401
Cash Flow Hedging | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized in OCI, net of taxes	(3,412)	0	(374)	$ 0
Amount of gain (loss) reclassified from accumulated OCI into income	0	0	0	0
Amount of gain (loss) recognized in income on derivative	0	0	0	(1)
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Contracts
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized in OCI, net of taxes	(3,412)	0	(374)	0
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Contracts | Other Income (Expense)
Derivative Instruments, Gain (Loss)
Amount of gain (loss) reclassified from accumulated OCI into income	0	0	0	0
Amount of gain (loss) recognized in income on derivative	$ 0	$ 0	$ 0	$ (1)

Shareholders' Equity, Capital75

Shareholders' Equity, Capital Ratios and Other Regulatory Matters (Details)	3 Months Ended
	Sep. 30, 2015USD ($)$ / sharesshares	Dec. 31, 2014$ / shares
Class of Stock
Preferred stock, par value (in usd per share)	$ 1	$ 1
Liquidation preference (per share)	$ 10,000	$ 10,000
Series B Preferred Stock
Class of Stock
Depositary shares issued | shares	3,200,000
Depository shares to preferred stock ratio	0.0025
Non-cumulative preferred stock, dividend rate	6.625%
Preferred stock, par value (in usd per share)	$ 1
Liquidation preference (per share)	$ 10,000
Depositary share issue price	25
Aggregate liquidation preference | $	$ 80,000,000
Series B Preferred Stock | Three-month LIBOR Rate
Class of Stock
Floating rate basis spread	4.262%

Shareholders' Equity, Capital76

Shareholders' Equity, Capital Ratios and Other Regulatory Matters - Actual Capital Amounts and Ratios (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Consolidated
Tier 1 Leverage
Minimum amount	$ 754,230	$ 602,387
Minimum ratio	4.00%	4.00%
Actual amount	$ 1,758,666	$ 1,408,842
Actual ratio	9.33%	9.36%
Common Equity Tier 1 (CET1)
Minimum amount	$ 737,629
Minimum ratio	4.50%
Actual amount	$ 1,652,078
Actual ratio	10.08%
Tier 1 Risk-Based Capital
Minimum amount	$ 983,506	$ 504,114
Minimum ratio	6.00%	4.00%
Actual amount	$ 1,758,666	$ 1,408,842
Actual ratio	10.73%	11.18%
Total Risk-Based Capital
Minimum amount	$ 1,311,341	$ 1,008,227
Minimum ratio	8.00%	8.00%
Actual amount	$ 1,990,821	$ 1,550,789
Actual ratio	12.15%	12.31%
IBERIABANK
Tier 1 Leverage
Minimum amount	$ 751,378	$ 600,149
Minimum ratio	4.00%	4.00%
Well capitalized amount	$ 939,222	$ 750,186
Well capitalized ratio	5.00%	5.00%
Actual amount	$ 1,647,804	$ 1,266,241
Actual ratio	8.77%	8.44%
Common Equity Tier 1 (CET1)
Minimum amount	$ 735,647
Minimum ratio	4.50%
Well capitalized amount	$ 1,062,601
Well capitalized ratio	6.50%
Actual amount	$ 1,647,804
Actual ratio	10.08%
Tier 1 Risk-Based Capital
Minimum amount	$ 980,863	$ 502,421
Minimum ratio	6.00%	4.00%
Well capitalized amount	$ 1,307,817	$ 753,631
Well capitalized ratio	8.00%	6.00%
Actual amount	$ 1,647,804	$ 1,266,241
Actual ratio	10.08%	10.08%
Total Risk-Based Capital
Minimum amount	$ 1,307,817	$ 1,004,841
Minimum ratio	8.00%	8.00%
Well capitalized amount	$ 1,634,772	$ 1,256,052
Well capitalized ratio	10.00%	10.00%
Actual amount	$ 1,792,584	$ 1,408,188
Actual ratio	10.97%	11.21%

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings per common share - basic
Net income	$ 42,475	$ 30,893	$ 98,437	$ 69,445
Dividends and undistributed earnings allocated to unvested restricted shares	(492)	(462)	(1,171)	(1,114)
Earnings Allocated to Common Shareholders	$ 41,983	$ 30,431	$ 97,266	$ 68,331
Weighted average common shares outstanding (in shares)	40,514,000	32,803,000	37,436,000	30,791,000
Earnings per common share - Basic (in usd per share)	$ 1.04	$ 0.93	$ 2.60	$ 2.22
Earnings per common share - diluted
Net income allocated to common shareholders - basic	$ 41,983	$ 30,431	$ 97,266	$ 68,331
Dividends and undistributed earnings allocated to unvested restricted shares	(3)	(4)	(41)	(24)
Net income allocated to common shareholders - diluted	$ 41,980	$ 30,427	$ 97,225	$ 68,307
Weighted average common shares outstanding (in shares)	40,514,000	32,803,000	37,436,000	30,791,000
Dilutive potential common shares - stock options (in shares)	100,000	124,000	96,000	132,000
Weighted average common shares outstanding - diluted (in shares)	40,614,000	32,927,000	37,532,000	30,923,000
Earnings per common share - Diluted (in usd per share)	$ 1.03	$ 0.92	$ 2.59	$ 2.21
Weighted average number of shares owned by Recognition and Retention Plan	616,307	621,341	606,621	630,320
Stock options having antidilutive effect on earnings per share	82,310	12,765	79,690	12,765

Share-Based Compensation (Detai

Share-Based Compensation (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award
Future awards shares under approved incentive compensation plans | shares	788,196
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Share-based compensation maximum option term (in years)	10 years
Unearned share-based compensation associated with awards	$ 3.1
Unrecognized compensation cost expected to be recognized over a weighted-average period (in years)	5 years 2 months 12 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award
Unearned share-based compensation associated with awards	$ 22.2
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Performance period (in years)	3 years
Phantom Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)	5 years
Phantom Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)	7 years

Share-Based Compensation - Acti

Share-Based Compensation - Activity Related to Stock Options (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Number of shares
Beginning balance (in shares)	867,682	1,072,829
Granted (in shares)	81,313	77,098
Exercised (in shares)	(95,265)	(234,363)
Forfeited or expired (in shares)	(15,733)	(13,446)
Ending balance (in shares)	837,997	902,118
Exercisable options (in shares)	570,148	581,423
Weighted Average Exercise Price
Beginning balance (in usd per share)	$ 55.92	$ 53.47
Granted (in usd per share)	62.53	65.30
Exercised (in usd per share)	50.64	48.36
Forfeited or expired (in usd per share)	66.57	60.82
Ending balance (in usd per share)	56.96	55.70
Exercisable options (in usd per share)	$ 56.53	$ 55.65

Share-Based Compensation - Esti

Share-Based Compensation - Estimate Fair Value of Stock Option Awards with Weighted-Average Assumptions (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected dividends	2.20%	2.10%
Expected volatility	35.60%	35.80%
Risk-free interest rate	2.00%	2.30%
Expected term (in years)	7 years 6 months	7 years 6 months
Weighted-average grant-date fair value	$ 19.60	$ 21.25

Share-Based Compensation - Comp

Share-Based Compensation - Compensation Expense Included in Non-Interest Expense Related to Stock Options (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Compensation expense	$ 455	$ 508	$ 1,400	$ 1,545
Restricted Stock Awards and Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Compensation expense	2,935	2,497	8,739	7,382
Phantom Stock and Performance Units
Share-based Compensation Arrangement by Share-based Payment Award
Compensation expense	$ 2,976	$ 619	$ 9,482	$ 3,692

Share-Based Compensation - Unve

Share-Based Compensation - Unvested Restricted Stock Award and Restricted Share Unit Activity (Detail) - shares	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares)	506,289	523,756
Granted (in shares)	203,762	165,634
Forfeited (in shares)	(23,471)	(18,171)
Earned and issued (in shares)	(170,513)	(152,112)
Ending balance (in shares)	516,067	519,107

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Share and Dividend Equivalent Share Award Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Share Equivalents [Roll Forward]
Beginning balance (in shares)	460,212	417,238
Granted (in shares)	156,505	115,620
Forfeited share equivalents (in shares)	(29,180)	(19,498)
Vested share equivalents (in shares)	(130,380)	(68,480)
Ending balance (in shares)	457,157	444,880
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Dividend Equivalents [Roll Forward]
Beginning balance (in shares)	22,648	22,351
Granted (in shares)	7,261	7,147
Forfeited share (in shares)	(1,541)	(1,751)
Vested share equivalents (in shares)	(9,134)	(6,615)
Ending balance (in shares)	19,234	21,132
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Total Share Equivalents [Roll Forward]
Beginning balance (in shares)	482,860	439,589
Granted (in shares)	163,766	122,767
Forfeited share equivalents (in shares)	(30,721)	(21,249)
Vested share equivalents (in shares)	(139,514)	(75,095)
Ending balance (in shares)	476,391	466,012
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Value of Share Equivalents [Roll Forward]
Beginning balance (in shares)	$ 31,313	$ 27,628
Granted (in shares)	9,533	7,674
Forfeited share equivalents (in shares)	(1,788)	(1,328)
Vested share equivalents (in shares)	(8,829)	(5,002)
Ending balance (in shares)	$ 27,731	$ 29,130
Market price of Company's stock (in usd per share)	$ 58.21	$ 62.51

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets
Securities available for sale	$ 2,827,805	$ 2,158,853
Mortgage loans held for sale	202,168	139,950
Derivative instruments	30,086	28,798
Liabilities
Derivative instruments	24,534	15,411
Level 1
Assets
Derivative instruments	0	0
Liabilities
Derivative instruments	0	0
Level 2
Assets
Derivative instruments	41,440	32,903
Liabilities
Derivative instruments	38,147	31,354
Level 3
Assets
Derivative instruments	0	0
Liabilities
Derivative instruments	0	0
Recurring
Assets
Securities available for sale	2,827,805	2,158,853
Mortgage loans held for sale	202,168	139,950
Derivative instruments	41,440	32,903
Total	3,071,413	2,331,706
Liabilities
Derivative instruments	38,147	31,354
Recurring | Level 1
Assets
Securities available for sale	0	0
Mortgage loans held for sale	0	0
Derivative instruments	0	0
Total	0	0
Liabilities
Derivative instruments	0	0
Recurring | Level 2
Assets
Securities available for sale	2,827,805	2,158,853
Mortgage loans held for sale	202,168	139,950
Derivative instruments	41,440	32,903
Total	3,071,413	2,331,706
Liabilities
Derivative instruments	38,147	31,354
Recurring | Level 3
Assets
Securities available for sale	0	0
Mortgage loans held for sale	0	0
Derivative instruments	0	0
Total	0	0
Liabilities
Derivative instruments	$ 0	$ 0

Fair Value Measurements - Gains

Fair Value Measurements - Gains and Losses Included in Earnings Related to Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Other Comprehensive Income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Change in unrealized net gains relating to assets still held at September 30, 2015	$ 9,458
Noninterest Income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation
Net gains included in earnings	$ 2,643

Fair Value Measurements - Fin86

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Property write-downs	$ 3,400	$ 1,900
Nonrecurring
Assets
OREO, net	1,904		$ 1,483
Total	1,904		1,483
Nonrecurring | Level 1
Assets
OREO, net	0		0
Total	0		0
Nonrecurring | Level 2
Assets
OREO, net	1,904		1,483
Total	1,904		1,483
Nonrecurring | Level 3
Assets
OREO, net	0		0
Total	$ 0		$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Difference Between the Aggregate Fair Value and the Aggregate Unpaid Principal Balance for Mortgage Loans Held for Sale (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Aggregate fair value	$ 202,168		$ 202,168		$ 139,950
Aggregate unpaid principal	194,376		194,376		134,639
Aggregate fair value less unpaid principal	7,792		7,792		$ 5,311
Net gain (loss) on change in Fair Value	$ 600	$ 1,600	$ 2,400	$ 4,000

Fair Value of Financial Instr88

Fair Value of Financial Instruments (Detail)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Short-term borrowings maturity period (days)	90 days

Fair Value of Financial Instr89

Fair Value of Financial Instruments - Estimated Fair Values and Carrying Amounts of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Financial Assets
Cash and cash equivalents	$ 682,272	$ 548,095	$ 668,007	$ 391,396
Loans and loans held for sale, net of unearned income and allowance for loan losses	14,319,187		11,229,417
FDIC loss share receivables	43,443	69,627	94,712	$ 162,312
Derivative instruments	30,086	28,798
Financial Liabilities
Deposits	16,303,065	12,520,525	$ 12,377,691
Short-term borrowings	222,460	845,742
Long-term debt	341,973	403,254
Derivative instruments	24,534	15,411
Level 1
Financial Assets
Cash and cash equivalents	682,272	548,095
Investment securities	0	0
Loans and loans held for sale, net of unearned income and allowance for loan losses	0	0
FDIC loss share receivables	0	0
Derivative instruments	0	0
Financial Liabilities
Deposits	0	0
Short-term borrowings	222,460	845,742
Long-term debt	0	0
Derivative instruments	0	0
Level 2
Financial Assets
Cash and cash equivalents	0	0
Investment securities	2,928,416	2,278,334
Loans and loans held for sale, net of unearned income and allowance for loan losses	212,764	139,950
FDIC loss share receivables	0	0
Derivative instruments	41,440	32,903
Financial Liabilities
Deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Derivative instruments	38,147	31,354
Level 3
Financial Assets
Cash and cash equivalents	0	0
Investment securities	0	0
Loans and loans held for sale, net of unearned income and allowance for loan losses	14,424,343	11,335,365
FDIC loss share receivables	8,437	19,606
Derivative instruments	0	0
Financial Liabilities
Deposits	15,996,499	12,298,017
Short-term borrowings	0	0
Long-term debt	311,982	376,139
Derivative instruments	0	0
Carrying Amount
Financial Assets
Cash and cash equivalents	682,272	548,095
Investment securities	2,926,135	2,275,813
Loans and loans held for sale, net of unearned income and allowance for loan losses	14,188,933	11,450,985
FDIC loss share receivables	43,443	69,627
Derivative instruments	41,440	32,903
Financial Liabilities
Deposits	16,303,065	12,520,525
Short-term borrowings	222,460	845,742
Long-term debt	341,973	403,254
Derivative instruments	38,147	31,354
Fair Value
Financial Assets
Cash and cash equivalents	682,272	548,095
Investment securities	2,928,416	2,278,334
Loans and loans held for sale, net of unearned income and allowance for loan losses	14,637,107	11,475,315
FDIC loss share receivables	8,437	19,606
Derivative instruments	41,440	32,903
Financial Liabilities
Deposits	15,996,499	12,298,017
Short-term borrowings	222,460	845,742
Long-term debt	311,982	376,139
Derivative instruments	$ 38,147	$ 31,354

Business Segments (Detail)

Business Segments (Detail)	9 Months Ended
	Sep. 30, 2015Segment
Segment Reporting [Abstract]
Number of business segments	3

Business Segments - Schedule of

Business Segments - Schedule of Segment Reporting Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information
Interest and dividend income	$ 171,077	$ 133,793	$ 470,207	$ 367,539
Interest expense	15,960	12,042	43,609	32,107
Net interest income	155,117	121,751	426,598	335,432
Provision for loan losses	5,062	5,714	19,197	12,565
Mortgage income	20,730	14,263	63,999	38,150
Title revenue	6,627	5,577	17,402	15,007
Other non-interest income	30,121	27,272	86,489	73,397
Allocated expenses	0	0	0	0
Non-interest expense	144,968	120,112	431,330	354,479
Income before income tax expense	62,565	43,037	143,961	94,942
Income tax expense	20,090	12,144	45,524	25,497
Net Income	42,475	30,893	98,437	69,445
Total loans and loans held for sale	14,319,187	11,229,417	14,319,187	11,229,417
Total assets	19,534,225	15,514,449	19,534,225	15,514,449	$ 15,757,904
Total deposits	16,303,065	12,377,691	16,303,065	12,377,691	$ 12,520,525
Average assets	19,604,070	15,476,208	18,015,680	14,300,952
Operating Segments | IBERIABANK
Segment Reporting Information
Interest and dividend income	169,005	131,987	464,775	362,974
Interest expense	15,109	11,416	41,410	30,784
Net interest income	153,896	120,571	423,365	332,190
Provision for loan losses	5,062	5,621	19,197	12,481
Mortgage income	365	(4)	932	80
Title revenue	0	0	0	0
Other non-interest income	30,120	27,310	86,498	73,459
Allocated expenses	(3,518)	(2,386)	(11,603)	(9,110)
Non-interest expense	124,909	104,172	373,948	308,515
Income before income tax expense	57,928	40,470	129,253	93,843
Income tax expense	18,253	11,128	39,695	25,038
Net Income	39,675	29,342	89,558	68,805
Total loans and loans held for sale	14,094,936	11,057,497	14,094,936	11,057,497
Total assets	19,242,690	15,288,142	19,242,690	15,288,142
Total deposits	16,293,681	12,371,522	16,293,681	12,371,522
Average assets	19,321,164	15,240,567	17,760,033	14,097,954
Operating Segments | IMC
Segment Reporting Information
Interest and dividend income	2,071	1,805	5,430	4,563
Interest expense	851	626	2,199	1,323
Net interest income	1,220	1,179	3,231	3,240
Provision for loan losses	0	93	0	84
Mortgage income	20,365	14,267	63,067	38,070
Title revenue	0	0	0	0
Other non-interest income	1	(36)	(2)	(60)
Allocated expenses	2,693	1,697	8,685	6,432
Non-interest expense	15,605	11,624	44,259	33,558
Income before income tax expense	3,288	1,996	13,352	1,176
Income tax expense	1,306	785	5,286	473
Net Income	1,982	1,211	8,066	703
Total loans and loans held for sale	224,251	171,920	224,251	171,920
Total assets	264,914	200,778	264,914	200,778
Total deposits	9,384	6,169	9,384	6,169
Average assets	256,897	210,345	230,379	177,995
Operating Segments | LTC
Segment Reporting Information
Interest and dividend income	1	1	2	2
Interest expense	0	0	0	0
Net interest income	1	1	2	2
Provision for loan losses	0	0	0	0
Mortgage income	0	0	0	0
Title revenue	6,627	5,577	17,402	15,007
Other non-interest income	0	(2)	(7)	(2)
Allocated expenses	825	689	2,918	2,678
Non-interest expense	4,454	4,316	13,123	12,406
Income before income tax expense	1,349	571	1,356	(77)
Income tax expense	531	231	543	(14)
Net Income	818	340	813	(63)
Total loans and loans held for sale	0	0	0	0
Total assets	26,621	25,529	26,621	25,529
Total deposits	0	0	0	0
Average assets	$ 26,009	$ 25,296	$ 25,268	$ 25,003

Commitments and Contingencies92

Commitments and Contingencies (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Fair value of guarantees under commercial and standby letters of credit	$ 1.5	$ 1.3

Commitments and Contingencies -

Commitments and Contingencies - Summary of Financial Instruments Outstanding (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Loss Contingencies
Reserve for unfunded lending commitments	$ 14,525	$ 11,801	$ 12,099	$ 11,147
Credit Risk Contract
Loss Contingencies
Commitments to grant loans	140,139	161,350
Unfunded commitments under lines of credit	4,602,464	4,007,954
Commercial and standby letters of credit	147,208	134,882
Reserve for unfunded lending commitments	$ 14,525	$ 11,801