Iberiabank (IBKC) 10-Q 7 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 31, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
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		41,074,368

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 327,799	$ 241,650
Interest-bearing deposits in banks	773,454	268,617
Total cash and cash equivalents	1,101,253	510,267
Securities available for sale, at fair value	2,885,413	2,800,286
Securities held to maturity (fair values of $93,410 and $100,961, respectively)	90,653	98,928
Mortgage loans held for sale, at fair value	210,866	166,247
Loans covered by loss share agreements	202,211	229,217
Non-covered loans, net of unearned income	14,722,288	14,098,211
Total loans, net of unearned income	14,924,499	14,327,428
Allowance for loan losses	(148,193)	(138,378)
Loans, net	14,776,306	14,189,050
FDIC loss share receivables	24,406	39,878
Premises and equipment, net	308,932	323,902
Goodwill	726,856	724,603
Other assets	663,881	650,907
Total Assets	20,788,566	19,504,068
Deposits:
Non-interest-bearing	4,787,485	4,352,229
Interest-bearing	11,735,032	11,826,519
Total deposits	16,522,517	16,178,748
Short-term borrowings	713,272	326,617
Long-term debt	672,438	340,447
Other liabilities	213,229	159,421
Total Liabilities	18,121,456	17,005,233
Shareholders’ Equity
Preferred stock, $1 par value - 5,000,000 shares authorized Non-cumulative perpetual, liquidation preference $10,000 per share; 13,750 and 8,000 shares issued and outstanding, including related surplus	132,097	76,812
Common stock, $1 par value - 100,000,000 shares authorized; 41,081,701 and 41,139,537 shares issued and outstanding, respectively	41,082	41,140
Additional paid-in capital	1,797,835	1,797,982
Retained earnings	676,308	584,486
Accumulated other comprehensive income (loss)	19,788	(1,585)
Total Shareholders’ Equity	2,667,110	2,498,835
Total Liabilities and Shareholders’ Equity	$ 20,788,566	$ 19,504,068

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Securities held to maturity, fair values	$ 93,410	$ 100,961
Preferred stock, par value (in usd per share)	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Liquidation preference (in usd per share)	$ 10,000	$ 10,000
Preferred stock, shares issued	13,750	8,000
Preferred stock, shares outstanding	13,750	8,000
Common stock, par value (in usd per share)	$ 1	$ 1
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	41,081,701	41,139,537
Common stock, shares outstanding	41,081,701	41,139,537

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest and Dividend Income
Loans, including fees	$ 167,784	$ 159,915	$ 497,344	$ 443,441
Mortgage loans held for sale, including fees	1,774	1,847	5,025	4,742
Investment securities:
Taxable interest	12,042	12,184	38,584	33,906
Tax-exempt interest	1,773	1,546	5,107	4,111
Amortization of FDIC loss share receivable	(3,935)	(5,600)	(12,484)	(19,011)
Other	1,066	1,185	2,558	3,018
Total interest and dividend income	180,504	171,077	536,134	470,207
Deposits:
NOW and MMDA	7,840	7,968	22,508	19,409
Savings	299	217	818	525
Time deposits	4,592	5,039	13,255	14,410
Short-term borrowings	753	116	1,900	699
Long-term debt	3,603	2,620	10,080	8,566
Total interest expense	17,087	15,960	48,561	43,609
Net interest income	163,417	155,117	487,573	426,598
Provision for loan losses	12,484	5,062	39,255	19,197
Net interest income after provision for loan losses	150,933	150,055	448,318	407,401
Non-interest Income
Mortgage income	21,807	20,628	67,738	63,897
Service charges on deposit accounts	11,066	11,342	32,957	30,766
Title revenue	6,001	6,627	16,881	17,402
Broker commissions	3,797	3,839	11,332	13,462
ATM/debit card fee income	3,483	3,562	10,636	10,420
Income from bank owned life insurance	1,305	1,093	3,918	3,260
Gain on sale of available for sale securities	12	280	1,997	1,569
Other non-interest income	12,350	10,107	35,124	27,114
Total non-interest income	59,821	57,478	180,583	167,890
Non-interest Expense
Salaries and employee benefits	85,028	82,416	250,875	239,131
Net occupancy and equipment	16,526	17,987	50,246	51,613
Communication and delivery	3,041	3,420	9,381	10,164
Marketing and business development	3,200	3,260	9,844	11,003
Data processing	6,076	6,727	18,095	27,928
Professional services	5,553	5,825	14,272	18,657
Credit and other loan related expense	1,928	5,241	7,530	14,154
Insurance	4,853	4,614	13,486	12,402
Travel and entertainment	1,915	2,248	6,236	7,489
Other non-interest expense	10,019	13,230	35,130	38,789
Total non-interest expense	138,139	144,968	415,095	431,330
Income before income tax expense	72,615	62,565	213,806	143,961
Income tax expense	24,547	20,090	72,159	45,524
Net Income	48,068	42,475	141,647	98,437
Preferred stock dividends	(3,590)	0	(7,020)	0
Income Available to Common Shareholders - Basic	44,478	42,475	134,627	98,437
Earnings Allocated to Unvested Restricted Stock	(462)	(492)	(1,464)	(1,171)
Earnings Allocated to Common Shareholders - Basic	$ 44,016	$ 41,983	$ 133,163	$ 97,266
Earnings per common share - Basic (in usd per share)	$ 1.08	$ 1.04	$ 3.27	$ 2.60
Earnings per common share - Diluted (in usd per share)	1.08	1.03	3.26	2.59
Cash dividends declared per share (in usd per share)	$ 0.36	$ 0.34	$ 1.04	$ 1.02
Comprehensive Income
Net Income	$ 48,068	$ 42,475	$ 141,647	$ 98,437
Unrealized gains (losses) on securities:
Unrealized holding gains (losses) arising during the period (net of tax effects of $3,410, $6,681, $15,605 and $5,843, respectively)	(6,334)	12,408	28,980	10,852
Reclassification adjustment for gains included in net income (net of tax effects of $4, $98, $699 and $549, respectively)	(8)	(182)	(1,298)	(1,020)
Unrealized gains (losses) on securities, net of tax	(6,342)	12,226	27,682	9,832
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 $78, $1,837, $3,397 and $201, respectively)	146	(3,412)	(6,309)	(374)
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	146	(3,412)	(6,309)	(374)
Other comprehensive income, net of tax	(6,196)	8,814	21,373	9,458
Comprehensive Income	$ 41,872	$ 51,289	$ 163,020	$ 107,895

Consolidated Statements of Com5

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Unrealized holding gains arising during the period, tax expense (benefit)	$ (3,410)	$ 6,681	$ 15,605	$ 5,843
Reclassification adjustment for gains included in net income, tax effects	4	98	699	549
Change in fair value of derivative instruments designated as cash flow hedges, tax expense (benefit)	$ 78	$ (1,837)	$ (3,397)	$ (201)

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, 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		(40,945)				(40,945)
Reclassification of treasury stock under the LBCA (in shares)	[1]			(1,809,497)
Reclassification of treasury stock under the LBCA	[1]	0		$ (1,809)	(84,037)			85,846
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
Preferred stock issued (in shares)			8,000
Preferred stock issued		77,463	$ 77,463		0
Common stock issued for acquisitions (in shares)				7,474,404
Common stock issued for acquisitions		474,753		$ 7,474	467,279
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	$ 77,463	$ 41,129	1,793,561	554,065	16,983	0
Beginning balance (in shares) at Dec. 31, 2015			8,000	41,139,537
Beginning balance at Dec. 31, 2015		2,498,835	$ 76,812	$ 41,140	1,797,982	584,486	(1,585)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		141,647				141,647
Other comprehensive income		21,373					21,373
Cash dividends declared		(42,805)				(42,805)
Preferred stock dividends		(7,020)				(7,020)
Common stock issued under incentive plans, net of shares surrendered in payment, including tax benefit (in shares)				144,670
Common stock issued under incentive plans, net of shares surrendered in payment, including tax benefit		232		$ 145	87
Preferred stock issued (in shares)			5,750
Preferred stock issued		55,285	$ 55,285
Common stock repurchases (in shares)				(202,506)
Common stock repurchases		(11,666)		$ (203)	(11,463)
Share-based compensation cost		11,229			11,229
Ending balance (in shares) at Sep. 30, 2016			13,750	41,081,701
Ending balance at Sep. 30, 2016		$ 2,667,110	$ 132,097	$ 41,082	$ 1,797,835	$ 676,308	$ 19,788	$ 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, Summary of Significant Accounting Policies, in the Annual Report on Form 10-K for the year ended December 31, 2015, for further discussion.

Consolidated Statements of Sha7

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per share (in usd per share)	$ 0.36	$ 0.34	$ 1.04	$ 1.02

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash Flows from Operating Activities
Net Income	$ 141,647	$ 98,437
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, and accretion	3,414	11,839
Amortization of purchase accounting adjustments, net	(13,803)	(14,657)
Provision for loan losses	39,255	19,197
Share-based compensation cost - equity awards	11,229	10,139
Gain on sale of assets, net	(64)	(2,384)
Gain on sale of available for sale securities	(1,997)	(1,569)
Gain on sale of OREO, net	(5,798)	(3,216)
Amortization of premium/discount on securities, net	16,288	13,217
Expense for deferred income taxes	3,008	3,244
Originations of mortgage loans held for sale	(1,922,021)	(1,880,856)
Proceeds from sales of mortgage loans held for sale	1,940,605	1,887,468
Realized and unrealized gains on mortgage loans held for sale, net	(77,271)	(60,109)
Tax benefit associated with share-based payment arrangements	(115)	(408)
Other operating activities, net	41,427	43,010
Net Cash Provided by Operating Activities	175,804	123,352
Cash Flows from Investing Activities
Proceeds from sales of available for sale securities	197,733	212,278
Proceeds from maturities, prepayments and calls of available for sale securities	349,361	367,064
Purchases of available for sale securities	(594,143)	(934,638)
Proceeds from maturities, prepayments and calls of held to maturity securities	7,597	17,937
Purchases of equity securities	(31,380)	0
Reimbursement of recoverable covered asset losses (to) from the FDIC	(7,173)	1,429
Increase in loans, net of loans acquired	(568,844)	(491,545)
Proceeds from sale of premises and equipment	1,200	9,113
Purchases of premises and equipment, net of premises and equipment acquired	(9,436)	(14,144)
Proceeds from disposition of OREO	28,089	38,739
Cash paid for additional investment in tax credit entities	(16,817)	(7,868)
Cash received in excess of cash paid for acquisitions	0	425,581
Other investing activities, net	(490)	14,695
Net Cash Used in Investing Activities	(644,303)	(361,359)
Cash Flows from Financing Activities
Increase in deposits, net of deposits acquired	344,130	1,092,943
Net change in short-term borrowings, net of borrowings acquired	386,655	(624,811)
Proceeds from long-term debt	346,754	63,125
Repayments of long-term debt	(13,826)	(200,031)
Cash dividends paid on common stock	(42,003)	(38,334)
Cash dividends paid on preferred stock	(6,077)	0
Net share-based compensation stock transactions	118	1,421
Payments to repurchase common stock	(11,666)	0
Net proceeds from issuance of preferred stock	55,285	77,463
Tax benefit associated with share-based payment arrangements	115	408
Net Cash Provided by Financing Activities	1,059,485	372,184
Net Increase in Cash and Cash Equivalents	590,986	134,177
Cash and Cash Equivalents at Beginning of Period	510,267	548,095
Cash and Cash Equivalents at End of Period	1,101,253	682,272
Supplemental Schedule of Non-cash Activities
Acquisition of real estate in settlement of loans	5,813	14,921
Common stock issued in acquisitions	0	474,753
Supplemental Disclosures Cash Paid For
Interest on deposits and borrowings	46,656	42,899
Income taxes, net	$ 54,560	$ 28,929

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION General The accompanying unaudited consolidated financial statements have been prepared in accordance with 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 the Company previously filed with the SEC in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. Operating results for the period ended September 30, 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016. When we refer to the “Company,” “we,” “our,” or “us” in this Report, we mean IBERIABANK Corporation and subsidiaries (consolidated). When we refer to the “Parent,” we mean IBERIABANK Corporation. See the Glossary of Acronyms at the end of this Report for terms used throughout this Report. Principles of Consolidation The Company’s consolidated financial statements include all entities in which the Company has a controlling financial interest under either the voting interest or variable interest model. The assessment of whether or not the Company has a controlling interest (i.e., the primary beneficiary) in a variable interest entity ("VIE") is performed on an on-going basis. All equity investments in non-consolidated VIEs are included in "other assets" in the Company’s consolidated balance sheets. The Company’s maximum exposure to loss as a result of its involvement with non-consolidated VIEs was approximately $130 million and $160 million at September 30, 2016 and December 31, 2015, respectively. The Company's maximum exposure to loss was equivalent to the carrying value of its investments and any related outstanding loans to the non-consolidated VIEs. Investments in entities that are not consolidated are accounted for under either the equity, cost, or proportional amortization method of accounting. Investments for which the Company has the ability to exercise significant influence over the operating and financing decisions of the entity are accounted for under the equity method. Investments for which the Company does not hold such ability are accounted for under the cost method. Investments in qualified affordable housing projects, which meet certain criteria, are accounted for under the proportional amortization method. The consolidated financial statements include the accounts of the Company and its subsidiaries, IBERIABANK; Lenders Title Company; IBERIA Capital Partners, LLC; 1887 Leasing, LLC; IBERIA Asset Management, Inc.; 840 Denning, LLC; and IBERIA CDE, LLC. All significant intercompany balances and transactions have been eliminated in consolidation. Nature of Operations 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 IMC 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 throughout the energy industry. 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 net impact on previously reported consolidated net income, shareholders’ equity or cash flows. 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, valuation of and accounting for acquired loans, goodwill and other intangibles, income taxes, and fair value estimates. 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. Concentrations in commercial real estate have increased as a result of the Company's recent acquisitions of CRE-focused banks. 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 and guarantor support. 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, 2016
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS ASU No. 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The most significant amendment to existing GAAP is the recognition of lease assets (i.e., right of use assets) and liabilities on the balance sheet for leases that are classified as operating leases by lessees. The lessor model remains similar to the current accounting model in existing GAAP. Additional amendments include, but are not limited to, the elimination of leveraged leases; modification to the definition of a lease; amendments on sale and leaseback transactions ; and disclosure of additional quantitative and qualitative information. ASU 2016-02 will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. Lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The Company is currently evaluating the impact of the ASU on the Company’s consolidated financial statements, including whether to adopt any practical expedients or policy elections from this ASU. The Company is not expecting to early adopt the ASU. ASU No. 2016-08, No. 2016-10, and No. 2016-12 In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , to improve implementation guidance on principal versus agency considerations within Topic 606. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , to improve implementation guidance on identifying performance obligations and licensing aspects of Topic 606. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , to provide clarification on certain targeted aspects of Topic 606. The amendments in ASU No. 2016-08, No. 2016-10, and No. 2016-12 will be effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that annual reporting period. The amendments will be applied through the election of one of two retrospective methods. The Company is currently evaluating the impact of the ASUs on the Company’s consolidated financial statements. The Company is not expecting to early adopt the ASUs. ASU No. 2016-09 In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendments will require recognition of excess tax benefits and deficiencies associated with awards which vest or settle within income tax expense or benefit in the statement of comprehensive income, with the tax effects treated as discrete items in the reporting period in which they occur. The ASU further requires entities to recognize excess tax benefits regardless of whether the benefit reduces taxes payable in the current period. This will eliminate the current APIC pool concept. The amendments will also allow an accounting policy election to account for forfeitures as they occur, permit an entity to withhold up to the maximum statutory tax rates in the applicable jurisdictions while still qualifying for equity classification, and change the classification of certain cash flows associated with stock compensation. ASU 2016-09 will be effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The transition method for implementing each amendment varies. The Company expects to elect an accounting policy to account for forfeitures as they occur upon adoption. Based on the Company's current stock valuation, it does not anticipate a significant impact to the Company's consolidated financial statements at adoption. ASU No. 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . The amendments introduce an impairment model that is based on expected credit losses (“ECL”), rather than incurred losses, to estimate credit losses on certain types of financial instruments (e.g., loans and held-to-maturity securities), including certain off-balance sheet financial instruments (e.g., loan commitments). The ECL should consider historical information, current information, and reasonable and supportable forecasts, including estimates of prepayments, over the contractual term. Financial instruments with similar risk characteristics may be grouped together when estimating the ECL. The ASU also amends the current AFS security impairment model for debt securities. The new model will require an estimate of ECL when the fair value is below the amortized cost of the asset through the use of an allowance to record estimated credit losses (and subsequent recoveries). Non-credit related losses will continue to be recognized through OCI. In addition, the amendments provide for a simplified accounting model for purchased financial assets with a more-than-insignificant amount of credit deterioration since their origination. The initial estimate of expected credit losses would be recognized through an ALL with an offset (i.e., increase) to the cost basis of the related financial asset at acquisition. ASU 2016-13 will be effective for fiscal years beginning after December 15, 2019, including interim periods. The amendments will be applied through a modified-retrospective approach, resulting in a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. A prospective transition approach is required for debt securities for which OTTI had been recognized before the effective date. Amounts previously recognized in AOCI as of the date of adoption that relate to improvements in cash flows expected to be collected should continue to be accreted into income over the remaining life of the asset. Recoveries of amounts previously written off relating to improvements in cash flows after the date of adoption should be recorded in earnings when received. The Company is currently evaluating the impact of the ASU on the Company’s consolidated financial statements. ASU No. 2016-15 In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , in order to reduce current diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 will be effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The amendments should be applied using a retrospective transition method to each period presented. The Company is currently evaluating the impact of the ASU on the Company’s consolidated statement of cash flows.

Acquisition Activity

Acquisition Activity	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Acquisition Activity	ACQUISITION ACTIVITY During 2015, the Company expanded its presence in Florida and Georgia through acquisitions of Florida Bank Group, Inc. on February 28, 2015, Old Florida Bancshares, Inc. on March 31, 2015, and Georgia Commerce Bancshares, Inc. on May 31, 2015. Further information on these acquisitions can be found in Note 3, Acquisition Activity, in the 2015 Annual Report on Form 10-K for the year ended December 31, 2015. The Company accounts for business combinations under the acquisition method in accordance with ASC Topic 805, Business Combinations . Accordingly, for each transaction, the purchase price is allocated to the fair value of the assets acquired and liabilities assumed as of the date of acquisition. In conjunction with the adoption of ASU 2015-16, upon receipt of final fair value estimates during the measurement period, which must be within one year of the acquisition dates, the Company records any adjustments to the preliminary fair value estimates in the reporting period in which the adjustments are determined. During the first quarter of 2016, the Company finalized the purchase price allocations related to the Florida Bank Group and Old Florida acquisitions. During the second quarter of 2016, the Company finalized the purchase price allocation related to the Georgia Commerce acquisition. The year-to-date impact of these adjustments was a $2.3 million increase to goodwill, with an offsetting decrease to net deferred tax assets. The following tables summarize the consideration paid, allocation of purchase price to net assets acquired and resulting goodwill for the aforementioned acquisitions. Acquisition of Florida Bank Group, Inc. (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 73,043 Goodwill $ 17,442 (Dollars in thousands) As Acquired 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 (5,371 ) (2) 307,531 Other real estate owned 498 (75 ) (3) 423 Core deposit intangible — 4,489 (4) 4,489 Deferred tax asset, net 18,151 8,569 (5) 26,720 Other assets 29,817 (8,949 ) (6) 20,868 Total Assets $ 541,586 $ (1,201 ) $ 540,385 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 1,898 4,618 (9) 6,516 Total Liabilities $ 453,863 $ 13,479 $ 467,342 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 values based on acquisition date 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 less costs to sell 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 adjustments 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 amount represents the adjustment of the book value of Florida Bank Group's time deposits to their estimated fair values at the date of acquisition. (8) The amount represents the adjustment of the book value of Florida Bank Group’s borrowings to their estimated fair value based on acquisition date 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. Acquisition of Old Florida Bancshares, Inc. (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 152,375 Goodwill $ 100,777 (Dollars in thousands) As Acquired 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 (10,822 ) (1) 1,062,951 Other real estate owned 4,515 1,449 (2) 5,964 Core deposit intangible — 6,821 (3) 6,821 Deferred tax asset, net 9,490 4,388 (4) 13,878 Other assets 30,549 (7,238 ) (5) 23,311 Total Assets $ 1,552,176 $ (5,402 ) $ 1,546,774 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 3,038 76 (7) 3,114 Total Liabilities $ 1,394,200 $ 199 $ 1,394,399 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 values based on acquisition date 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 less costs to sell 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 amount represents the adjustment of the book value of Old Florida's time deposits to their estimated fair values on the date of acquisition. (7) The adjustment is necessary to record Old Florida's rent liability at fair value. Acquisition of Georgia Commerce Bancshares, Inc (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 103,569 Goodwill $ 86,695 (Dollars in thousands) As Acquired Fair Value As recorded by Assets Cash and cash equivalents $ 51,059 $ — $ 51,059 Investment securities 135,710 (807 ) (1) 134,903 Loans held for sale 1,249 — 1,249 Loans 807,726 (15,607 ) (2) 792,119 Other real estate owned 9,795 (4,207 ) (3) 5,588 Core deposit intangible — 6,720 (4) 6,720 Deferred tax asset, net 3,603 5,452 (5) 9,055 Other assets 28,956 (657 ) (6) 28,299 Total Assets $ 1,038,098 $ (9,106 ) $ 1,028,992 Liabilities Interest-bearing deposits 658,133 176 (7) 658,309 Non-interest-bearing deposits 249,739 — 249,739 Borrowings 13,204 — 13,204 Other liabilities 4,171 — 4,171 Total Liabilities $ 925,247 $ 176 $ 925,423 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 acquisition date 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 less costs to sell 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 amount represents the adjustment of the book value of Georgia Commerce's time deposits to their estimated fair values at the date of acquisition.

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2016
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, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 217,859 $ 2,613 $ — $ 220,472 Obligations of states and political subdivisions 245,086 7,946 (127 ) 252,905 Mortgage-backed securities 2,283,336 29,475 (1,743 ) 2,311,068 Other securities 99,688 1,330 (50 ) 100,968 Total securities available for sale $ 2,845,969 $ 41,364 $ (1,920 ) $ 2,885,413 Securities held to maturity: Obligations of states and political subdivisions $ 64,898 $ 2,727 $ — $ 67,625 Mortgage-backed securities 25,755 205 (175 ) 25,785 Total securities held to maturity $ 90,653 $ 2,932 $ (175 ) $ 93,410 December 31, 2015 Amortized Cost Gross Gross (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 252,514 $ 1,161 $ (1,592 ) $ 252,083 Obligations of states and political subdivisions 182,541 5,429 (9 ) 187,961 Mortgage-backed securities 2,272,879 8,457 (16,523 ) 2,264,813 Other securities 95,496 430 (497 ) 95,429 Total securities available for sale $ 2,803,430 $ 15,477 $ (18,621 ) $ 2,800,286 Securities held to maturity: Obligations of states and political subdivisions $ 69,979 $ 2,803 $ (101 ) $ 72,681 Mortgage-backed securities 28,949 107 (776 ) 28,280 Total securities held to maturity $ 98,928 $ 2,910 $ (877 ) $ 100,961 Securities with carrying values of $1.3 billion and $1.4 billion were pledged to secure public deposits and other borrowings at September 30, 2016 and December 31, 2015 , 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, 2016 Less Than Twelve Months Over Twelve Months Total Gross Unrealized Losses Fair Value Gross Gross (Dollars in thousands) Securities available for sale: Obligations of state and political obligations $ (127 ) $ 30,222 $ — $ — $ (127 ) $ 30,222 Mortgage-backed securities (893 ) 236,800 (850 ) 94,259 (1,743 ) 331,059 Other securities (1 ) 507 (49 ) 3,916 (50 ) 4,423 Total securities available for sale $ (1,021 ) $ 267,529 $ (899 ) $ 98,175 $ (1,920 ) $ 365,704 Securities held to maturity: Obligations of states and political subdivisions $ — $ 2,212 $ — $ — $ — $ 2,212 Mortgage-backed securities — — (175 ) 11,698 (175 ) 11,698 Total securities held to maturity $ — $ 2,212 $ (175 ) $ 11,698 $ (175 ) $ 13,910 December 31, 2015 Less Than Twelve Months Over Twelve Months Total Gross Gross Gross (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ (1,214 ) $ 177,839 $ (378 ) $ 28,116 $ (1,592 ) $ 205,955 Obligations of states and political subdivisions (9 ) 5,765 — — (9 ) 5,765 Mortgage-backed securities (11,737 ) 1,279,914 (4,786 ) 185,215 (16,523 ) 1,465,129 Other securities (488 ) 51,975 (9 ) 499 (497 ) 52,474 Total securities available for sale $ (13,448 ) $ 1,515,493 $ (5,173 ) $ 213,830 $ (18,621 ) $ 1,729,323 Securities held to maturity: Obligations of states and political subdivisions $ (9 ) $ 1,999 $ (92 ) $ 4,162 $ (101 ) $ 6,161 Mortgage-backed securities (45 ) 3,530 (731 ) 17,573 (776 ) 21,103 Total securities held to maturity $ (54 ) $ 5,529 $ (823 ) $ 21,735 $ (877 ) $ 27,264 The Company assessed the nature of the losses in its portfolio as of September 30, 2016 and December 31, 2015 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, 2016 or December 31, 2015 . At September 30, 2016 , 73 debt securities had unrealized losses of 0.55% of the securities’ amortized cost basis. At December 31, 2015 , 252 debt securities had unrealized losses of 1.10% 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, 2016 and December 31, 2015 is presented in the following table. (Dollars in thousands) September 30, 2016 December 31, 2015 Number of securities Issued by Fannie Mae, Freddie Mac, or Ginnie Mae 27 40 Issued by political subdivisions — 2 Other 3 1 30 43 Amortized cost basis Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 106,982 $ 236,800 Issued by political subdivisions — 4,253 Other 3,965 508 $ 110,947 $ 241,561 Unrealized loss Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 1,025 $ 5,895 Issued by political subdivisions — 92 Other 49 9 $ 1,074 $ 5,996 The Fannie Mae, Freddie Mac, and Ginnie Mae securities are rated AA+ by Standard & Poor's and Aaa by Moody’s. The amortized cost and estimated fair value of investment securities by maturity at September 30, 2016 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 2.36 % $ 19,560 $ 19,658 2.42 % $ 2,059 $ 2,076 One through five years 1.64 % 275,596 279,271 2.97 % 10,295 10,583 After five through ten years 2.29 % 585,382 602,194 3.07 % 18,357 19,214 Over ten years 1.97 % 1,965,431 1,984,290 2.74 % 59,942 61,537 2.01 % $ 2,845,969 $ 2,885,413 2.82 % $ 90,653 $ 93,410 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) 2016 2015 2016 2015 Realized gains $ 12 $ 425 $ 2,947 $ 1,786 Realized losses — (145 ) (950 ) (217 ) $ 12 $ 280 $ 1,997 $ 1,569 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, 2016 December 31, 2015 Federal Home Loan Bank (FHLB) stock $ 47,589 $ 16,265 Federal Reserve Bank (FRB) stock 48,584 48,584 Other investments 1,159 1,159 $ 97,332 $ 66,008

Loans

Loans	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Loans	LOANS Loans consist of the following, segregated into legacy and acquired loans, for the periods indicated: September 30, 2016 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Real estate $ 5,419,483 $ 1,261,732 $ 6,681,215 Commercial and industrial 3,101,472 361,525 3,462,997 Energy-related 598,279 1,362 599,641 9,119,234 1,624,619 10,743,853 Residential mortgage loans: 840,082 430,448 1,270,530 Consumer and other loans: Home equity 1,755,295 395,835 2,151,130 Indirect automobile 153,904 9 153,913 Other 544,855 60,218 605,073 2,454,054 456,062 2,910,116 Total $ 12,413,370 $ 2,511,129 $ 14,924,499 December 31, 2015 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Real estate $ 4,504,062 $ 1,569,449 $ 6,073,511 Commercial and industrial 2,952,102 492,476 3,444,578 Energy-related 677,177 3,589 680,766 8,133,341 2,065,514 10,198,855 Residential mortgage loans: 694,023 501,296 1,195,319 Consumer and other loans: Home equity 1,575,643 490,524 2,066,167 Indirect automobile 246,214 84 246,298 Other 541,299 79,490 620,789 2,363,156 570,098 2,933,254 Total $ 11,190,520 $ 3,136,908 $ 14,327,428 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 were covered by loss share agreements between the FDIC and IBERIABANK, which afforded IBERIABANK loss protection. Covered loans, which are included in acquired loans in the tables above, were $202.2 million and $229.2 million at September 30, 2016 and December 31, 2015, respectively, of which $169.0 million and $191.7 million , respectively, were residential mortgage and home equity loans. Refer to Note 7 for additional information regarding the Company’s loss sharing agreements. Net deferred loan origination fees were $20.9 million and $18.7 million at September 30, 2016 and December 31, 2015 , 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, 2016 and December 31, 2015 , overdrafts of $3.8 million and $5.1 million , respectively, have been reclassified to loans. Loans with carrying values of $4.3 billion and $ 3.9 billion were pledged as collateral for borrowings at September 30, 2016 and December 31, 2015 , respectively. Aging Analysis The following tables provide an analysis of the aging of loans as of September 30, 2016 and December 31, 2015 . Due to the difference in accounting for acquired loans, the tables below further segregate the Company’s loans between loans originated by the Company (“legacy loans”) and acquired loans. September 30, 2016 Legacy loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due Non-accrual Loans Total Loans Commercial real estate - Construction $ 694,868 $ — $ — $ 1,234 $ 1,234 $ 25 $ 696,127 Commercial real estate - Other 4,704,088 1,514 445 2,389 4,348 14,920 4,723,356 Commercial and industrial 3,050,241 14,713 1,404 148 16,265 34,966 3,101,472 Energy-related 444,659 — — — — 153,620 598,279 Residential mortgage 817,154 1,396 7,389 327 9,112 13,816 840,082 Consumer - Home equity 1,740,001 6,207 1,968 101 8,276 7,018 1,755,295 Consumer - Indirect automobile 150,008 2,151 405 — 2,556 1,340 153,904 Consumer - Credit card 79,588 311 115 — 426 438 80,452 Consumer - Other 459,548 2,145 994 737 3,876 979 464,403 Total $ 12,140,155 $ 28,437 $ 12,720 $ 4,936 $ 46,093 $ 227,122 $ 12,413,370 December 31, 2015 Legacy loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due Non-accrual Loans Total Loans Commercial real estate - Construction $ 635,560 $ 801 $ — $ — $ 801 $ 120 $ 636,481 Commercial real estate - Other 3,848,584 2,687 793 95 3,575 15,422 3,867,581 Commercial and industrial 2,943,409 1,208 739 87 2,034 6,659 2,952,102 Energy-related 670,081 15 — — 15 7,081 677,177 Residential mortgage 676,347 1,075 2,485 442 4,002 13,674 694,023 Consumer - Home equity 1,565,596 3,549 870 — 4,419 5,628 1,575,643 Consumer - Indirect automobile 242,328 2,187 518 — 2,705 1,181 246,214 Consumer - Credit card 76,360 394 113 — 507 394 77,261 Consumer - Other 460,594 1,923 752 — 2,675 769 464,038 Total $ 11,118,859 $ 13,839 $ 6,270 $ 624 $ 20,733 $ 50,928 $ 11,190,520 September 30, 2016 Acquired loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due (1) (2) Non-accrual Loans Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - Construction $ 41,618 $ — $ — $ — $ — $ 1,946 $ (285 ) $ 37,516 $ 80,795 Commercial real estate - Other 913,519 — 387 — 387 1,976 (4,991 ) 270,046 1,180,937 Commercial and industrial 324,496 561 249 — 810 1,770 (705 ) 35,154 361,525 Energy-related 1,369 — — — — — (7 ) — 1,362 Residential mortgage 307,677 — 1,339 280 1,619 1,258 (5,855 ) 125,749 430,448 Consumer - Home equity 301,164 419 289 17 725 1,206 (1,762 ) 94,502 395,835 Consumer - Indirect automobile 9 — — — — — — — 9 Consumer - Credit Card — — — — — — — 507 507 Consumer - Other 57,929 521 203 — 724 243 (4,758 ) 5,573 59,711 Total $ 1,947,781 $ 1,501 $ 2,467 $ 297 $ 4,265 $ 8,399 $ (18,363 ) $ 569,047 $ 2,511,129 December 31, 2015 Acquired loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due (1) (2) Non-accrual Loans Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - Construction $ 69,167 $ 180 $ 117 $ — $ 297 $ — $ (358 ) $ 56,320 $ 125,426 Commercial real estate - Other 1,090,688 861 705 — 1,566 1,491 (4,479 ) 354,757 1,444,023 Commercial and industrial 442,454 623 — — 623 1,154 (2,517 ) 50,762 492,476 Energy-related 2,186 — — — — 170 2 1,231 3,589 Residential mortgage 365,261 7 940 — 947 1,109 (6,601 ) 140,580 501,296 Consumer - Home equity 381,107 622 416 291 1,329 1,291 (7,333 ) 114,130 490,524 Consumer - Indirect automobile 19 — — — — — — 65 84 Consumer - Credit Card — — — — — — — 582 582 Consumer - Other 74,385 468 127 — 595 206 (2,570 ) 6,292 78,908 Total $ 2,425,267 $ 2,761 $ 2,305 $ 291 $ 5,357 $ 5,421 $ (23,856 ) $ 724,719 $ 3,136,908 (1) Past due information presents acquired loans at the gross loan balance, prior to application of discounts. (2) Past due loan amounts exclude acquired impaired loans, even if contractually past due or if the Company does not expect to receive payment in full, as the Company is currently accreting interest income over the expected life of the loans. Loans Acquired As discussed in Note 3, during 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 $57.8 million were determined to exhibit deteriorated credit quality since origination under ASC 310-30. The tables below show the balances acquired during 2015 for these two subsections of the portfolio as of the acquisition date. (Dollars in thousands) Acquired Non-Impaired Loans Contractually required principal and interest at acquisition $ 2,384,114 Expected losses and foregone interest (15,539 ) Cash flows expected to be collected at acquisition 2,368,575 Fair value of acquired loans at acquisition $ 2,105,466 (Dollars in thousands) Acquired Impaired Loans Contractually required principal and interest at acquisition $ 76,445 Non-accretable difference (expected losses and foregone interest) (11,867 ) Cash flows expected to be collected at acquisition 64,578 Accretable yield (6,823 ) Basis in acquired loans at acquisition $ 57,755 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: (Dollars in thousands) 2016 2015 Balance at beginning of period $ 227,502 $ 287,651 Acquisition — 4,592 Transfers from non-accretable difference to accretable yield 5,491 7,199 Accretion (52,603 ) (60,305 ) Changes in expected cash flows not affecting non-accretable differences (1) 12,743 (1,511 ) Balance at end of period $ 193,133 $ 237,626 (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, 2016 and 2015 is presented in the following tables. Modifications of loans that are accounted for within a pool under ASC Topic 310-30, which include covered loans, 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 $218.6 million and $ 48.6 million occurred during the nine -month periods ended September 30, 2016 and September 30, 2015 , respectively, through modification of the original loan terms. The following table provides information on how the TDRs were modified during the nine months ended September 30: (Dollars in thousands) 2016 2015 Extended maturities $ 76,059 $ 15,932 Maturity and interest rate adjustment 26,372 23,552 Forbearance 75,953 1,228 Movement to or extension of interest-rate only payments 1,689 — Interest rate adjustment 133 — Other concession(s) (1) 38,390 7,887 Total $ 218,596 $ 48,599 (1) Other concessions may include covenant waivers, forgiveness of principal or interest associated with a customer bankruptcy, or a combination of any of the above concessions. Of the $218.6 million of TDRs occurring during the nine -month period ended September 30, 2016 , $94.3 million are on accrual status and $124.3 million are on non-accrual status. Of the $48.6 million of TDRs occurring during the nine-month period ended September 30, 2015 , $21.8 million were on accrual status and $26.8 million were on non-accrual status at September 30, 2015. The following table presents the end of period balance for loans modified in a TDR during the nine-month periods ended September 30: 2016 2015 (In thousands, except number of loans) Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Commercial real estate 23 $ 22,765 $ 16,441 8 $ 26,408 $ 25,572 Commercial and industrial 49 44,144 43,083 18 19,798 19,643 Energy-related 28 143,012 145,298 1 3,434 3,384 Residential mortgage 31 4,784 4,659 — — — Consumer - Home Equity 104 7,071 6,805 — — — Consumer - Other 142 2,372 2,310 — — — Total 377 $ 224,148 $ 218,596 27 $ 49,640 $ 48,599 Information detailing TDRs which defaulted during the nine-month periods ended September 30, 2016 and 2015 , and 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, 2016 September 30, 2015 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate 5 $ 668 4 $ 12,939 Commercial and industrial 21 7,476 15 13,145 Energy-related 1 1,394 1 3,384 Residential mortgage 5 364 — — Consumer - Home Equity 16 1,037 — — Consumer - Other 13 278 — — Total 61 $ 11,217 20 $ 29,468

Allowance for Credit Losses and

Allowance for Credit Losses and Credit Quality	9 Months Ended
	Sep. 30, 2016
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 nine months ended September 30 is as follows: 2016 (Dollars in thousands) Legacy Loans Acquired Loans Total Allowance for credit losses Allowance for loan losses at beginning of period $ 93,808 $ 44,570 $ 138,378 Provision for (Reversal of) loan losses before benefit attributable to FDIC loss share agreements 40,516 (2,501 ) 38,015 Adjustment attributable to FDIC loss share arrangements — 1,240 1,240 Net provision for loan losses 40,516 (1,261 ) 39,255 Adjustment attributable to FDIC loss share arrangements — (1,240 ) (1,240 ) Transfer of balance to OREO and other — (2,045 ) (2,045 ) Loans charged-off (28,559 ) (1,495 ) (30,054 ) Recoveries 3,124 775 3,899 Allowance for loan losses at end of period $ 108,889 $ 39,304 $ 148,193 Reserve for unfunded commitments at beginning of period 14,145 — 14,145 Provision for (Reversal of) unfunded lending commitments (2,155 ) — (2,155 ) Reserve for unfunded commitments at end of period $ 11,990 $ — $ 11,990 Allowance for credit losses at end of period $ 120,879 $ 39,304 $ 160,183 2015 (Dollars in thousands) Legacy Loans Acquired Loans Total Allowance for credit losses Allowance for loan losses at beginning of period $ 76,174 $ 53,957 $ 130,131 Provision for loan losses before benefit attributable to FDIC loss share agreements 17,743 112 17,855 Adjustment attributable to FDIC loss share arrangements — 1,342 1,342 Net provision for loan losses 17,743 1,454 19,197 Adjustment attributable to FDIC loss share arrangements — (1,342 ) (1,342 ) Transfer of balance to OREO and other — (9,768 ) (9,768 ) Loans charged-off (12,073 ) (952 ) (13,025 ) Recoveries 4,556 505 5,061 Allowance for loan losses at end of period $ 86,400 $ 43,854 $ 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 $ 43,854 $ 144,779 A summary of changes in the allowance for credit losses for legacy loans, by loan portfolio type, for the nine months ended September 30 is as follows: 2016 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loan losses at beginning of period $ 24,658 $ 23,283 $ 23,863 $ 3,947 $ 18,057 $ 93,808 Provision for (Reversal of) loan losses (651 ) 13,201 18,998 248 8,720 40,516 Loans charged off (1,598 ) (2,418 ) (14,672 ) (240 ) (9,631 ) (28,559 ) Recoveries 766 251 — 142 1,965 3,124 Allowance for loan losses at end of period $ 23,175 $ 34,317 $ 28,189 $ 4,097 $ 19,111 $ 108,889 Reserve for unfunded commitments at beginning of period $ 4,160 $ 3,448 $ 2,665 $ 830 $ 3,042 $ 14,145 Provision for (Reversal of) unfunded commitments (427 ) (46 ) (1,712 ) (148 ) 178 (2,155 ) Reserve for unfunded commitments at end of period $ 3,733 $ 3,402 $ 953 $ 682 $ 3,220 $ 11,990 Allowance on loans individually evaluated for impairment $ 655 $ 8,996 $ 14,396 $ 110 $ 1,053 $ 25,210 Allowance on loans collectively evaluated for impairment 22,520 25,321 13,793 3,987 18,058 83,679 Loans, net of unearned income: Balance at end of period $ 5,419,483 $ 3,101,472 $ 598,279 $ 840,082 $ 2,454,054 $ 12,413,370 Balance at end of period individually evaluated for impairment 31,405 58,464 212,512 4,539 11,546 318,466 Balance at end of period collectively evaluated for impairment 5,388,078 3,043,008 385,767 835,543 2,442,508 12,094,904 2015 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loan losses at beginning of period $ 26,752 $ 24,455 $ 5,949 $ 2,678 $ 16,340 $ 76,174 Provision for (Reversal of) loan losses (947 ) 1,308 9,269 1,474 6,639 17,743 Loans charged off (2,009 ) (1,048 ) — (224 ) (8,792 ) (12,073 ) Recoveries 1,535 49 — 44 2,928 4,556 Allowance for loan losses at end of period $ 25,331 $ 24,764 $ 15,218 $ 3,972 $ 17,115 $ 86,400 Reserve for unfunded commitments at beginning of period $ 3,370 $ 3,733 $ 1,596 $ 168 $ 2,934 $ 11,801 Provision for (Reversal of) unfunded commitments 218 (149 ) 2,037 650 (32 ) 2,724 Reserve for unfunded commitments at end of period $ 3,588 $ 3,584 $ 3,633 $ 818 $ 2,902 $ 14,525 Allowance on loans individually evaluated for impairment $ 883 $ 817 $ — $ — $ — $ 1,700 Allowance on loans collectively evaluated for impairment 24,448 23,947 15,218 3,972 17,115 84,700 Loans, net of unearned income: Balance at end of period $ 4,321,723 $ 2,779,503 $ 713,935 $ 660,543 $ 2,303,554 $ 10,779,258 Balance at end of period individually evaluated for impairment 26,463 22,076 3,409 — 198 52,146 Balance at end of period collectively evaluated for impairment 4,295,260 2,757,427 710,526 660,543 2,303,356 10,727,112 A summary of changes in the allowance for credit losses for acquired loans, by loan portfolio type, for the nine months ended September 30 is as follows: 2016 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loan losses at beginning of period $ 25,979 $ 2,819 $ 125 $ 7,841 $ 7,806 $ 44,570 Provision for (Reversal of) loan losses (1,952 ) 216 (99 ) 1,017 (443 ) (1,261 ) Decrease in FDIC loss share receivable (34 ) (50 ) — (833 ) (323 ) (1,240 ) Transfer of balance to OREO and other (380 ) (467 ) — 28 (1,226 ) (2,045 ) Loans charged off (789 ) — — — (706 ) (1,495 ) Recoveries 102 217 — 33 423 775 Allowance for loan losses at end of period $ 22,926 $ 2,735 $ 26 $ 8,086 $ 5,531 $ 39,304 Allowance on loans individually evaluated for impairment $ 177 $ 77 $ — $ — $ — $ 254 Allowance on loans collectively evaluated for impairment 22,749 2,658 26 8,086 5,531 39,050 Loans, net of unearned income: Balance at end of period $ 1,261,732 $ 361,525 $ 1,362 $ 430,448 $ 456,062 $ 2,511,129 Balance at end of period individually evaluated for impairment 5,647 1,926 — — 679 8,252 Balance at end of period collectively evaluated for impairment 948,523 324,445 1,362 304,699 354,801 1,933,830 Balance at end of period acquired with deteriorated credit quality 307,562 35,154 — 125,749 100,582 569,047 2015 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 29,949 $ 3,265 $ 51 $ 6,484 $ 14,208 $ 53,957 Provision for (Reversal of) loan losses 809 174 67 1,263 (859 ) 1,454 (Decrease) Increase in FDIC loss share receivable 748 59 — (277 ) (1,872 ) (1,342 ) Transfer of balance to OREO and other (6,096 ) (282 ) — (472 ) (2,918 ) (9,768 ) Loans charged off — (8 ) — (59 ) (885 ) (952 ) Recoveries 8 116 — 4 377 505 Allowance for loans losses at end of period $ 25,418 $ 3,324 $ 118 $ 6,943 $ 8,051 $ 43,854 Allowance on loans individually evaluated for impairment $ — $ — $ — $ — $ 16 $ 16 Allowance on loans collectively evaluated for impairment 25,418 3,324 118 6,943 8,035 43,838 Loans, net of unearned income: Balance at end of period $ 1,658,028 $ 523,468 $ 5,521 $ 529,398 $ 621,346 $ 3,337,761 Balance at end of period individually evaluated for impairment — 142 — — 456 598 Balance at end of period collectively evaluated for impairment 1,205,439 465,514 5,521 385,854 493,032 2,555,360 Balance at end of period acquired with deteriorated credit quality 452,589 57,812 — 143,544 127,858 781,803 Portfolio Segment Risk Factors Commercial real estate loans include loans to commercial customers for long-term financing of land and buildings or for land development or construction of a building. These loans are repaid through revenues from operations of the businesses, rents of properties and refinances. Commercial and industrial loans represent loans to commercial customers to finance general working capital needs, equipment purchases and other projects where repayment is derived from cash flows resulting from business operations. The Company originates commercial business loans on a secured and, to a lesser extent, unsecured basis. Residential mortgage loans consist of loans to consumers to finance a primary residence. The vast majority of the residential mortgage loan portfolio is comprised of one-to-four family mortgage loans secured by properties located in the Company's market areas and originated under terms and documentation that permit sale in the secondary market. Consumer loans are offered by the Company in order to provide a full range of retail financial services to its customers and include home equity, credit card and other direct consumer installment loans. The Company originates substantially all of its consumer loans in its primary market areas. Loans in the consumer segment are sensitive to unemployment and other key consumer economic measures. Credit Quality The Company utilizes an asset risk classification system in accordance with guidelines established by the Federal Reserve Board as part of its efforts to monitor commercial asset quality. "Special mention" loans are defined as loans where known information about possible credit problems of the borrower cause management to have some doubt as to the ability of these borrowers to comply with the present loan repayment terms and which may result in future disclosures of these loans as non-performing. For assets with identified credit issues, the Company has two primary classifications for problem assets: "substandard" and "doubtful". Substandard assets have one or more defined weaknesses and are characterized by the distinct possibility that the Company will sustain some loss if the deficiencies are not corrected. Doubtful assets have the weaknesses of the substandard assets with the additional characteristic that the weaknesses make collection or liquidation in full satisfaction of the loan balance outstanding questionable, which makes probability of loss based on currently existing facts, conditions, and values higher. Loans classified as "Pass" do not meet the criteria set forth for special mention, substandard, or doubtful classification and are not considered criticized. Asset risk classifications are determined at origination or acquisition and reviewed on an ongoing basis. Risk classifications are changed if, in the opinion of management, the risk profile of the customer has changed since the last review of the loan relationship. The Company’s investment in loans by credit quality indicator is presented in the following tables. The tables below further segregate the Company’s loans between loans that were originated by the Company (legacy loans) and acquired loans. 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, 2016 and December 31, 2015 . 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, 2016 and December 31, 2015 . Loan delinquency is the primary credit quality indicator that the Company utilizes to monitor consumer asset quality. Legacy loans September 30, 2016 December 31, 2015 (Dollars in thousands) Pass Special Mention Sub-standard Doubtful Loss Total Pass Special Mention Sub-standard Doubtful Loss Total Commercial real estate - Construction $ 694,983 $ 84 $ 1,060 $ — $ — $ 696,127 $ 634,889 $ 160 $ 1,432 $ — $ — $ 636,481 Commercial real estate - Other 4,654,619 22,919 45,656 162 — 4,723,356 3,806,528 21,877 37,001 2,175 — 3,867,581 Commercial and industrial 2,994,661 34,249 53,951 18,611 — 3,101,472 2,911,396 14,826 19,888 5,992 — 2,952,102 Energy-related 279,404 65,263 249,640 3,972 — 598,279 531,657 67,937 74,272 3,311 — 677,177 Total $ 8,623,667 $ 122,515 $ 350,307 $ 22,745 $ — $ 9,119,234 $ 7,884,470 $ 104,800 $ 132,593 $ 11,478 $ — $ 8,133,341 Legacy loans September 30, 2016 December 31, 2015 (Dollars in thousands) Current 30+ Days Past Due Total Current 30+ Days Past Due Total Residential mortgage $ 817,154 $ 22,928 $ 840,082 $ 676,347 $ 17,676 $ 694,023 Consumer - Home equity 1,740,001 15,294 1,755,295 1,565,596 10,047 1,575,643 Consumer - Indirect automobile 150,008 3,896 153,904 242,328 3,886 246,214 Consumer - Credit card 79,588 864 80,452 76,360 901 77,261 Consumer - Other 459,548 4,855 464,403 460,594 3,444 464,038 Total $ 3,246,299 $ 47,837 $ 3,294,136 $ 3,021,225 $ 35,954 $ 3,057,179 Acquired loans September 30, 2016 December 31, 2015 (Dollars in thousands) Pass Special Mention Sub- standard Doubtful Loss Premium/(Discount) Total Pass Special Mention Sub- standard Doubtful Loss Premium/(Discount) Total Commercial real estate-Construction $ 63,139 $ 140 $ 5,167 $ 744 $ — $ 11,605 $ 80,795 $ 104,064 $ 1,681 $ 8,803 $ 771 $ — $ 10,107 $ 125,426 Commercial real estate - Other 1,145,942 21,731 46,941 1,484 23 (35,184 ) 1,180,937 1,395,884 26,080 79,119 6,124 111 (63,295 ) 1,444,023 Commercial and industrial 361,376 6,216 14,443 558 — (21,068 ) 361,525 473,241 8,376 16,510 1,206 43 (6,900 ) 492,476 Energy-related 1,369 — — — — (7 ) 1,362 2,166 55 170 1,198 — — 3,589 Total $ 1,571,826 $ 28,087 $ 66,551 $ 2,786 $ 23 $ (44,654 ) $ 1,624,619 $ 1,975,355 $ 36,192 $ 104,602 $ 9,299 $ 154 $ (60,088 ) $ 2,065,514 Acquired loans September 30, 2016 December 31, 2015 (Dollars in thousands) Current 30+ Days Past Due Premium (Discount) Total Current 30+ Days Past Due Premium (Discount) Total Residential mortgage $ 441,411 $ 21,832 $ (32,795 ) $ 430,448 $ 506,103 $ 24,752 $ (29,559 ) $ 501,296 Consumer - Home equity 408,541 11,458 (24,164 ) 395,835 503,635 16,381 (29,492 ) 490,524 Consumer - Indirect automobile 9 1 (1 ) 9 72 12 — 84 Consumer - Other 58,998 1,618 (398 ) 60,218 79,732 1,475 (1,717 ) 79,490 Total $ 908,959 $ 34,909 $ (57,358 ) $ 886,510 $ 1,089,542 $ 42,620 $ (60,768 ) $ 1,071,394 Legacy Impaired Loans Information on the Company’s investment in legacy impaired loans, which include all TDRs and all other non-accrual loans, is presented in the following tables as of and for the periods indicated. Legacy non-accrual mortgage and consumer loans, and commercial loans below the Company's specific threshold, are included for purposes of this disclosure although such loans are generally not evaluated or measured individually for impairment for purposes of determining the allowance for loan losses. September 30, 2016 December 31, 2015 Unpaid Principal Balance Recorded Investment Related Allowance Unpaid Principal Balance Recorded Investment Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 15,447 $ 14,655 $ — $ 17,002 $ 16,145 $ — Commercial business 29,162 28,722 — 14,571 14,340 — Energy-related 168,723 163,156 — — — — Residential mortgage — — — — — — Consumer - Home equity — — — 730 730 — Consumer -Other — — — 66 66 — With an allowance recorded: Commercial real estate 17,870 17,843 (660 ) 21,377 13,753 (1,253 ) Commercial and industrial 31,406 31,067 (9,012 ) 7,422 6,262 (277 ) Energy-related 52,749 49,407 (14,396 ) 13,474 13,444 (2,125 ) Residential mortgage 18,205 16,840 (124 ) 14,806 13,743 (64 ) Consumer - Home equity 16,845 15,615 (855 ) 9,486 8,559 (363 ) Consumer - Indirect automobile 2,465 1,727 (128 ) 1,955 1,181 (10 ) Consumer - Credit card 438 438 (9 ) 394 394 (8 ) Consumer - Other 2,711 2,573 (122 ) 1,450 899 (23 ) Total $ 356,021 $ 342,043 $ (25,306 ) $ 102,733 $ 89,516 $ (4,123 ) Total commercial loans $ 315,357 $ 304,850 $ (24,068 ) $ 73,846 $ 63,944 $ (3,655 ) Total mortgage loans 18,205 16,840 (124 ) 14,806 13,743 (64 ) Total consumer loans 22,459 20,353 (1,114 ) 14,081 11,829 (404 ) 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 Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 20,345 $ 220 $ 16,018 $ 37 $ 20,633 $ 663 $ 16,036 $ 79 Commercial and industrial 29,533 313 20,055 159 30,772 1,030 20,630 465 Energy-related 165,459 1,364 3,409 — 149,099 3,755 3,425 — Residential mortgage — — — — — — — — Consumer - Home equity — — 215 3 — — 204 4 With an allowance recorded: Commercial real estate 17,776 143 11,649 128 17,654 433 8,247 385 Commercial and industrial 31,859 366 2,121 — 39,087 1,211 2,634 — Energy-related 55,947 416 99 — 42,089 1,325 106 — Residential mortgage 16,558 49 15,008 — 16,410 177 15,100 — Consumer - Home equity 14,632 119 5,344 — 13,696 348 5,462 — Consumer - Indirect automobile 1,853 16 1,361 — 2,092 70 1,551 — Consumer - Credit card 468 — 721 — 461 — 1,038 — Consumer - Other 2,346 38 1,030 — 2,065 109 1,068 — Total $ 356,776 $ 3,044 $ 77,030 $ 327 334,058 9,121 $ 75,501 $ 933 Total commercial loans $ 320,919 $ 2,822 $ 53,351 $ 324 $ 299,334 $ 8,417 $ 51,078 $ 929 Total mortgage loans 16,558 49 15,008 — 16,410 177 15,100 — Total consumer loans 19,299 173 8,671 3 18,314 527 9,323 4 As of September 30, 2016 and December 31, 2015 , 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, 2016
Loss Sharing Agreements and FDIC Loss Share Receivable [Abstract]
Loss Sharing Agreements and FDIC Loss Share Receivable	LOSS SHARING AGREEMENTS AND FDIC LOSS SHARE RECEIVABLES 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 subject to 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 ended during the third quarter of 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 the year-to-date activity for the FDIC loss share receivables: Nine Months Ended September 30, (Dollars in thousands) 2016 2015 Balance at beginning of period $ 39,878 $ 69,627 Reversal of loan loss provision recorded on FDIC covered loans (1,240 ) (1,342 ) Amortization (12,484 ) (19,011 ) Submission of reimbursable losses to the FDIC (1,760 ) (4,084 ) Changes in cash flow assumptions on OREO and other adjustments 12 (1,747 ) Balance at end of period $ 24,406 $ 43,443 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, 2016, the Company concluded that the $24.4 million FDIC loss share receivable is fully collectible as of September 30, 2016.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2016
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, 2016, and the year ended December 31, 2015 are provided in the following table. (Dollars in thousands) IBERIABANK IMC LTC Total Balance, December 31, 2014 $ 489,183 $ 23,178 $ 5,165 $ 517,526 Goodwill acquired during the year 207,077 — — 207,077 Balance, December 31, 2015 $ 696,260 $ 23,178 $ 5,165 $ 724,603 Goodwill adjustments during the period 2,253 — — 2,253 Balance, September 30, 2016 $ 698,513 $ 23,178 $ 5,165 $ 726,856 The goodwill adjustments during the first nine months of 2016 are the result of updates to preliminary fair value estimates related to the 2015 acquisitions of Florida Bank Group, Old Florida, and Georgia Commerce, during the respective measurement periods. See Note 3 for further information on these acquisitions. The Company performed the required annual goodwill impairment test as of October 1, 2015. 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 evaluated the events and changes that could 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, 2016. 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, 2016 December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Mortgage servicing rights $ 6,295 $ (2,945 ) $ 3,350 $ 6,104 $ (2,320 ) $ 3,784 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, 2016 and December 31, 2015 . No events or changes in circumstances occurred during the nine months ended September 30, 2016 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, 2016 December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Core deposit intangibles $ 74,001 $ (50,128 ) $ 23,873 $ 74,001 $ (43,957 ) $ 30,044 Customer relationship intangible asset 1,348 (1,013 ) 335 1,348 (984 ) 364 Non-compete agreement 62 (18 ) 44 100 (79 ) 21 Other intangible assets — — — 205 (114 ) 91 Total $ 75,411 $ (51,159 ) $ 24,252 $ 75,654 $ (45,134 ) $ 30,520

Derivative Instruments and Othe

Derivative Instruments and Other Hedging Activities	9 Months Ended
	Sep. 30, 2016
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, exposures related to liquidity and credit risk, and to facilitate customer transactions. 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. The Company has designated interest rate swaps in a cash flow hedge to convert forecasted variable interest payments to a fixed rate on its junior subordinated debt and has concluded that the forecasted transactions are probable of occurring. 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: Asset Derivatives Fair Value Liability Derivatives Fair Value (Dollars in thousands) Balance September 30, 2016 December 31, 2015 Balance September 30, 2016 December 31, 2015 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts Other $ — $ 58 Other $ 9,649 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ 58 $ 9,649 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts Other $ 39,438 $ 18,077 Other $ 39,563 $ 18,077 Foreign exchange contracts Other 44 156 Other 30 134 Forward sales contracts Other 105 1,588 Other 1,680 474 Written and purchased options Other 16,217 10,607 Other 8,017 6,254 Total derivatives not designated as hedging instruments under ASC Topic 815 55,804 30,428 49,290 24,939 Total $ 55,804 $ 30,486 $ 58,939 $ 24,939 Asset Derivatives Liability Derivatives (Dollars in thousands) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts $ — $ 108,500 $ 108,500 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ 108,500 $ 108,500 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts $ 976,456 $ 590,334 $ 976,456 $ 590,334 Foreign exchange contracts 4,644 4,392 4,644 4,392 Forward sales contracts 53,662 223,841 405,697 173,430 Written and purchased options 400,129 328,210 167,211 181,949 Total derivatives not designated as hedging instruments under ASC Topic 815 1,434,891 1,146,777 1,554,008 950,105 Total $ 1,434,891 $ 1,255,277 $ 1,662,508 $ 950,105 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, 2016 and December 31, 2015 , the Company was required to post $58.0 million and $20.1 million , respectively, in cash, which is included in "interest-bearing deposits in banks", or securities as collateral for its derivative transactions, 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, 2016 . 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, 2016 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 39,438 $ — $ — $ 39,438 Written and purchased options 7,998 — — 7,998 Total derivative assets subject to master netting arrangements $ 47,436 $ — $ — $ 47,436 Derivative liabilities Interest rate contracts designated as hedging instruments $ 9,649 $ — $ (12,752 ) $ (3,103 ) Interest rate contracts not designated as hedging instruments 39,563 — (45,247 ) (5,684 ) Total derivative liabilities subject to master netting arrangements $ 49,212 $ — $ (57,999 ) $ (8,787 ) (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. December 31, 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 $ 58 $ — $ — $ 58 Interest rate contracts not designated as hedging instruments 18,058 — — 18,058 Written and purchased options 6,277 — — 6,277 Total derivative assets subject to master netting arrangements $ 24,393 $ — $ — $ 24,393 Derivative liabilities Interest rate contracts not designated as hedging instruments $ 18,058 $ — $ (20,104 ) $ (2,046 ) Total derivative liabilities subject to master netting arrangements $ 18,058 $ — $ (20,104 ) $ (2,046 ) (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. During the nine months ended September 30, 2016 and 2015 , 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, 2016 , 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, 2016 and 2015, 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 2016 2015 2016 2015 2016 2015 Interest rate contracts $ 146 $ (3,412 ) Other income (expense) $ — $ — Other income (expense) $ — $ — Total $ 146 $ (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 2016 2015 2016 2015 2016 2015 Interest rate contracts $ (6,309 ) $ (374 ) Other income (expense) $ — $ — Other income (expense) $ — $ — Total $ (6,309 ) $ (374 ) $ — $ — $ — $ — Information pertaining to the effect of derivatives not designated as hedging instruments on the consolidated financial statements is as follows: Amount of Gain (Loss) Recognized Location of Gain (Loss) For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2016 2015 2016 2015 Interest rate contracts (1) Other income $ 2,215 $ 1,130 $ 7,509 $ 3,069 Foreign exchange contracts Other income 4 — 7 — Forward sales contracts Mortgage income (2,590 ) (6,524 ) (12,720 ) 1,526 Written and purchased options Mortgage income (2,624 ) (526 ) 3,846 (1,711 ) Total $ (2,995 ) $ (5,920 ) $ (1,358 ) $ 2,884 (1) Includes fees associated with customer interest rate contracts.

Shareholders' Equity, Capital R

Shareholders' Equity, Capital Ratios and Other Regulatory Matters	9 Months Ended
	Sep. 30, 2016
Banking and Thrift [Abstract]
Shareholders' Equity, Capital Ratios and Other Regulatory Matters	SHAREHOLDERS' EQUITY, CAPITAL RATIOS AND OTHER REGULATORY MATTERS The Company and IBERIABANK are subject to various regulatory capital frameworks administered by federal and state 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. Effective January 1, 2016, the Company was subject to an additional 25% phase out of its trust preferred securities from Tier 1 Risk-Based Capital. As a result, 100% of the Company's trust preferred securities are excluded from Tier 1 Risk-Based Capital at September 30, 2016 . Additionally, the Company and IBERIABANK's Common Equity Tier 1 Capital, Tier 1 Risk-Based Capital, and Total Risk-Based Capital were impacted at September 30, 2016 by an additional 20% phase out of certain intangible assets above the December 31, 2015 phase out percentage. Management believes that, as of September 30, 2016 , the Company and IBERIABANK met all capital adequacy requirements to which they are subject. As of September 30, 2016 , 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, 2016 and December 31, 2015 are presented in the following table. September 30, 2016 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 784,103 4.00 % N/A N/A $ 1,901,866 9.70 % IBERIABANK 781,582 4.00 976,978 5.00 1,831,469 9.37 Common Equity Tier 1 (CET1) Consolidated $ 785,140 4.50 % N/A N/A $ 1,769,769 10.14 % IBERIABANK 783,333 4.50 1,131,481 6.50 1,831,469 10.52 Tier 1 Risk-Based Capital Consolidated $ 1,046,854 6.00 % N/A N/A $ 1,901,866 10.90 % IBERIABANK 1,044,444 6.00 1,392,591 8.00 1,831,469 10.52 Total Risk-Based Capital Consolidated $ 1,395,805 8.00 % N/A N/A $ 2,178,549 12.49 % IBERIABANK 1,392,591 8.00 1,740,739 10.00 1,991,651 11.44 December 31, 2015 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 751,798 4.00 % N/A N/A $ 1,790,034 9.52 % IBERIABANK 749,226 4.00 936,532 5.00 1,691,022 9.03 Common Equity Tier 1 (CET1) Consolidated $ 752,610 4.50 % N/A N/A $ 1,684,097 10.07 % IBERIABANK 750,660 4.50 1,084,287 6.50 1,691,022 10.14 Tier 1 Risk-Based Capital Consolidated $ 1,003,479 6.00 % N/A N/A $ 1,790,034 10.70 % IBERIABANK 1,000,880 6.00 1,334,507 8.00 1,691,022 10.14 Total Risk-Based Capital Consolidated $ 1,337,973 8.00 % N/A N/A $ 2,029,932 12.14 % IBERIABANK 1,334,507 8.00 1,668,133 10.00 1,843,545 11.05 Beginning January 1, 2016, minimum CET1, Tier 1 Risk-Based Capital, and Total Risk-Based Capital ratios are 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% . At September 30, 2016 , the capital conservation buffers of the Company and IBERIABANK were 4.49% and 3.44% , respectively. On May 9, 2016, the Company issued an aggregate of 2,300,000 depositary shares (the “Depositary Shares”), each representing a 1/400th ownership interest in a share of the Company’s 6.60% Fixed-to-Floating Non-Cumulative Perpetual Preferred Stock, Series C, par value $1.00 per share, (“Series C Preferred Stock”), with a liquidation preference of $10,000 per share of Series C Preferred Stock (equivalent to $25 per depositary share), which represents $57,500,000 in aggregate liquidation preference. Dividends will accrue and be payable on the Series C preferred stock, subject to declaration by the Company’s board of directors, from the date of issuance to, but excluding May 1, 2026, at a rate of 6.60% per annum, payable quarterly, in arrears, and from and including May 1, 2026, dividends will accrue and be payable at a floating rate equal to three-month LIBOR plus a spread of 492 basis points, payable quarterly, in arrears. The Company may redeem the Series C preferred stock at its option, subject to regulatory approval, as described in the Prospectus. On May 4, 2016, the Company's Board of Directors authorized the repurchase of up to 950,000 shares of IBERIABANK Corporation's outstanding common stock. Stock repurchases under this program will be made from time to time, on the open market or in privately negotiated transactions. The timing of these repurchases will depend on market conditions and other requirements. The Company anticipates the share repurchase program will extend over a 2 -year time frame, or earlier if the shares have been repurchased. The share repurchase program does not obligate the Company to repurchase any dollar amount or number of shares, and the program may be extended, modified, suspended, or discontinued at any time. During the second quarter of 2016, the Company repurchased 202,506 common shares at a weighted average price of $57.61 per common share. The Company did not repurchase any common shares during the third quarter of 2016.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2016
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) 2016 2015 2016 2015 Earnings per common share - basic Net income $ 48,068 $ 42,475 $ 141,647 $ 98,437 Preferred stock dividends (3,590 ) — (7,020 ) — Dividends and undistributed earnings allocated to unvested restricted shares (462 ) (492 ) (1,464 ) (1,171 ) Earnings allocated to common shareholders - basic $ 44,016 $ 41,983 $ 133,163 $ 97,266 Weighted average common shares outstanding 40,618 40,514 40,699 37,436 Earnings per common share - basic $ 1.08 $ 1.04 $ 3.27 $ 2.60 Earnings per common share - diluted Earnings allocated to common shareholders - basic $ 44,016 $ 41,983 $ 133,163 $ 97,266 Dividends and undistributed earnings allocated to unvested restricted shares (4 ) (3 ) (17 ) (41 ) Earnings allocated to common shareholders - diluted $ 44,012 $ 41,980 $ 133,146 $ 97,225 Weighted average common shares outstanding 40,618 40,514 40,699 37,436 Dilutive potential common shares - stock options 193 100 119 96 Weighted average common shares outstanding - diluted 40,811 40,614 40,818 37,532 Earnings per common share - diluted $ 1.08 $ 1.03 $ 3.26 $ 2.59 For the three months ended September 30, 2016 , and 2015 , the calculations for basic shares outstanding exclude the weighted average shares owned by the Recognition and Retention Plan (“RRP”) of 434,468 , and 616,307 , respectively. For the nine months ended September 30, 2016, and 2015, basic shares outstanding exclude 456,921 and 606,621 shares owned by the RRP, respectively. The effects from the assumed exercises of 73,882 and 82,310 stock options were not included in the computation of diluted earnings per share for the three months ended September 30, 2016 , and 2015 , respectively, because such amounts would have had an antidilutive effect on earnings per common share. For the nine months ended September 30, 2016, and 2015, the effects from the assumed exercise of 268,257 and 79,690 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, 2016
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, 2016 , awards of 2,468,506 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, 2015 813,777 $ 56.99 Granted 152,209 47.63 Exercised (72,258 ) 55.28 Forfeited or expired (49,636 ) 60.06 Outstanding options, September 30, 2016 844,092 $ 55.27 Exercisable options, September 30, 2016 538,751 $ 56.40 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 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 following periods: For the Nine Months Ended September 30 2016 2015 Expected dividends 2.9 % 2.2 % Expected volatility 29.1 % 35.6 % Risk-free interest rate 1.4 % 2.0 % Expected term (in years) 6.5 7.5 Weighted-average grant-date fair value $ 10.16 $ 19.60 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 following periods: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2016 2015 2016 2015 Compensation expense related to stock options $ 513 $ 455 $ 1,500 $ 1,400 At September 30, 2016 , there was $2.5 million of unrecognized compensation cost related to stock options that is expected to be recognized over a weighted-average period of 2.4 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, 2016 and 2015 , unrecognized share-based compensation associated with these awards totaled $18.3 million and $22.2 million , respectively. Restricted share units During the first nine months of 2016 and 2015 , 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 periods indicated: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2016 2015 2016 2015 Compensation expense related to restricted stock awards and restricted share units $ 3,014 $ 2,935 $ 9,729 $ 8,739 The following table represents unvested restricted stock award and restricted share unit activity for the following periods: For the Nine Months Ended September 30 2016 2015 Balance at beginning of period 507,130 506,289 Granted 244,074 203,762 Forfeited (16,890 ) (23,471 ) Earned and issued (184,873 ) (170,513 ) Balance at end of period 549,441 516,067 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 2015 , the Company issued 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) 2016 2015 2016 2015 Compensation expense related to phantom stock and performance units $ 3,127 $ 2,976 $ 8,325 $ 9,482 The following table represents phantom stock award and performance unit activity during the periods indicated: (Dollars in thousands) Number of share equivalents (1) Value of share equivalents (2) Balance, December 31, 2015 462,430 $ 25,466 Granted 200,761 13,475 Forfeited share equivalents (27,267 ) 1,830 Vested share equivalents (158,491 ) 8,161 Balance, September 30, 2016 477,433 $ 32,045 Balance, December 31, 2014 475,347 $ 30,826 Granted 162,740 9,473 Forfeited share equivalents (28,728 ) 1,672 Vested share equivalents (138,678 ) 8,832 Balance, September 30, 2015 470,681 $ 27,398 (1) Number of share equivalents includes all reinvested dividend equivalents for the periods indicated. (2) 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 $67.12 and $58.21 on September 30, 2016 , and 2015 , respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Recurring fair value measurements 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. See Note 1, Summary of Significant Accounting Policies, in the 2015 Annual Report on Form 10-K for the year ended December 31, 2015, for a description of how fair value measurements are determined. September 30, 2016 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,885,413 $ — $ 2,885,413 Mortgage loans held for sale — 210,866 — 210,866 Derivative instruments — 55,804 — 55,804 Total $ — $ 3,152,083 $ — $ 3,152,083 Liabilities Derivative instruments $ — $ 58,939 $ — $ 58,939 Total $ — $ 58,939 $ — $ 58,939 December 31, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,800,286 $ — $ 2,800,286 Mortgage loans held for sale — 166,247 — 166,247 Derivative instruments — 30,486 — 30,486 Total $ — $ 2,997,019 $ — $ 2,997,019 Liabilities Derivative instruments $ — $ 24,939 $ — $ 24,939 Total $ — $ 24,939 $ — $ 24,939 During the nine months ended September 30, 2016 there were no transfers between the Level 1 and Level 2 fair value categories. Non-recurring fair value measurements The Company has segregated all 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, 2016 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 85,463 $ 85,463 OREO, net — — 405 405 Total $ — $ — $ 85,868 $ 85,868 December 31, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 31,669 $ 31,669 OREO, net — — 1,662 1,662 Total $ — $ — $ 33,331 $ 33,331 The tables above exclude the initial measurement of assets and liabilities that were acquired as part of the acquisitions completed in 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, property, equipment, and debt) or Level 3 fair value measurements (loans, OREO, deposits, and core deposit intangible assets). In accordance with the provisions of ASC Topic 310, the Company records certain loans considered impaired at their estimated fair value. A loan is considered impaired if it is probable the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. Fair value is measured at the estimated fair value of the collateral for collateral-dependent loans. Impaired loans with an unpaid principal balance of $120.6 million and $40.2 million were recorded at their fair value at September 30, 2016 and December 31, 2015, respectively. These loans include reserves and charge-offs of $35.2 million and $8.5 million included in the Company's allowance for credit losses at September 30, 2016 and December 31, 2015, respectively. 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, 2016 and December 31, 2015 . 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. During the third quarter, an immaterial amount of mortgage loans held for sale for which the fair value option was elected were transferred from loans held for sale to loans held for investment. 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, 2016 December 31, 2015 (Dollars in thousands) Aggregate Aggregate Aggregate Aggregate Aggregate Aggregate Mortgage loans held for sale, at fair value $ 210,866 $ 203,293 $ 7,573 $ 166,247 $ 161,083 $ 5,164 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 (losses) 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, 2016 totaled ( $1.5 million ) and $2.4 million , respectively, while net gains resulting from the change in fair value of these loans were $7 thousand and $3.7 million for the three and nine months ended September 30, 2015 , respectively. 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, 2016
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 carrying amount and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments are included in the tables below. See Note 1, Summary of Significant Accounting Policies, in the 2015 Annual Report on Form 10-K for the year ended December 31, 2015, for a description of how fair value measurements are determined. September 30, 2016 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 1,101,253 $ 1,101,253 $ 1,101,253 $ — $ — Investment securities 2,976,066 2,978,823 — 2,978,823 — Loans and loans held for sale, net of unearned income and allowance for loan losses 14,987,172 15,032,960 — 210,866 14,822,094 FDIC loss share receivables 24,406 6,343 — — 6,343 Derivative instruments 55,804 55,804 — 55,804 — Financial Liabilities Deposits $ 16,522,517 $ 16,485,224 $ — $ — $ 16,485,224 Short-term borrowings 713,272 713,272 353,272 360,000 — Long-term debt 672,438 660,140 — — 660,140 Derivative instruments 58,939 58,939 — 58,939 — December 31, 2015 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 510,267 $ 510,267 $ 510,267 $ — $ — Investment securities 2,899,214 2,901,247 — 2,901,247 — Loans and loans held for sale, net of unearned income and allowance for loan losses 14,355,297 14,674,749 — 166,247 14,508,502 FDIC loss share receivables 39,878 9,163 — — 9,163 Derivative instruments 30,486 30,486 — 30,486 — Financial Liabilities Deposits $ 16,178,748 $ 15,696,245 $ — $ — $ 15,696,245 Short-term borrowings 326,617 326,617 216,617 110,000 — Long-term debt 340,447 309,847 — — 309,847 Derivative instruments 24,939 24,939 — 24,939 — The fair value estimates presented herein are based upon pertinent information available to management as of September 30, 2016 and December 31, 2015 .

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS Each of the Company’s reportable operating segments 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 primarily reflect the manner in which resources are allocated and performance is assessed. Further, the reportable operating segments are also determined based on the quantitative thresholds prescribed within ASC Topic 280, Segment Reporting , and consideration of the usefulness of the information to the users of the consolidated financial statements. The Company reports the results of its operations through three reportable 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. 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 methods that reflect utilization. Also, within IBERIABANK are certain reconciling items that 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, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 178,521 $ 1,982 $ 1 $ 180,504 Interest expense 15,944 1,143 — 17,087 Net interest income 162,577 839 1 163,417 Provision for loan losses 12,443 41 — 12,484 Mortgage income 850 20,957 — 21,807 Service charges on deposit accounts 11,066 — — 11,066 Title revenue — — 6,001 6,001 Other non-interest income 20,946 1 — 20,947 Allocated expenses (3,914 ) 3,010 904 — Non-interest expense 127,690 5,891 4,558 138,139 Income before income tax expense 59,220 12,855 540 72,615 Income tax expense 19,282 5,048 217 24,547 Net income $ 39,938 $ 7,807 $ 323 $ 48,068 Total loans and loans held for sale, net of unearned income $ 14,957,337 $ 178,028 $ — $ 15,135,365 Total assets 20,537,304 226,906 24,356 20,788,566 Total deposits 16,513,867 8,650 — 16,522,517 Average assets 20,061,071 305,996 25,761 20,392,828 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 263 20,365 — 20,628 Service charges on deposit accounts 11,342 — — 11,342 Title revenue — — 6,627 6,627 Other non-interest income 18,880 1 — 18,881 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, net of unearned income $ 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 Nine Months Ended September 30, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 530,409 $ 5,723 $ 2 $ 536,134 Interest expense 45,380 3,181 — 48,561 Net interest income 485,029 2,542 2 487,573 Provision for loan losses 39,214 41 — 39,255 Mortgage income 856 66,882 — 67,738 Service charges on deposit accounts 32,957 — — 32,957 Title revenue — — 16,881 16,881 Other non-interest income 62,999 8 — 63,007 Allocated expenses (10,468 ) 8,007 2,461 — Non-interest expense 367,985 33,909 13,201 415,095 Income before income tax expense 185,110 27,475 1,221 213,806 Income tax expense 60,841 10,826 492 72,159 Net income $ 124,269 $ 16,649 $ 729 $ 141,647 Total loans and loans held for sale, net of unearned income $ 14,957,337 $ 178,028 $ — $ 15,135,365 Total assets 20,537,304 226,906 24,356 20,788,566 Total deposits 16,513,867 8,650 — 16,522,517 Average assets 19,705,052 289,037 26,626 20,020,715 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 830 63,067 — 63,897 Service charges on deposit accounts 30,766 — — 30,766 Title revenue — — 17,402 17,402 Other non-interest income 55,834 (2 ) (7 ) 55,825 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, net of unearned income $ 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

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Off-balance sheet commitments In the normal course of business, to meet the financing needs of its customers, the Company is a party to credit related financial instruments, with risk not reflected in the consolidated financial statements. 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, 2016 and December 31, 2015 , the fair value of guarantees under commercial and standby letters of credit was $1.7 million and $1.5 million , respectively. These amounts represent the unamortized fees associated with the 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. At September 30, 2016 and December 31, 2015, respectively, the Company had the following financial instruments outstanding and related reserves, whose contract amounts represent credit risk: (Dollars in thousands) September 30, 2016 December 31, 2015 Commitments to grant loans $ 398,754 $ 61,240 Unfunded commitments under lines of credit 4,876,141 4,617,802 Commercial and standby letters of credit 165,365 150,281 Reserve for unfunded lending commitments 11,990 14,145 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 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 guarantees 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. When necessary they are collateralized, 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, 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. In July of 2016, a subsidiary of IBERIABANK received a subpoena from the Office of Inspector General of the U.S. Department of Housing and Urban Development (“HUD”) requesting information on certain previously originated loans insured by the Federal Housing Administration ("FHA") as well as other documents regarding the subsidiary's FHA-related policies and practices. The Company is cooperating with HUD and is in the process of responding to the subpoena. Given the current status of the matter, the Company is unable to determine if its submission of the information requested will result in an additional information request by HUD and/or further proceedings by HUD or other government agencies. 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 currently expected to have a material adverse effect on the Company’s consolidated financial position, consolidated results of operations, or consolidated cash flows. However, it is possible that the ultimate resolution of these matters, or any unasserted claims, 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.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS In the ordinary course of business, the Company may execute transactions with various related parties. These transactions are consummated at terms equivalent to the prevailing market rates and terms at the time. Examples of such transactions may include lending or deposit arrangements, transfers of financial assets, services for administrative support, and other miscellaneous items. The Company has granted loans to executive officers and directors and their affiliates. These loans, including the related principal additions, principal payments, and unfunded commitments are immaterial to the consolidated financial statements at September 30, 2016 and December 31, 2015. None of the related party loans were classified as non-accrual, past due, troubled debt restructurings, or potential problem loans at September 30, 2016 or December 31, 2015, with the exception of the loan discussed below. IBERIABANK and several other financial institutions have extended credit (the “Credit Facility”) under a multi-bank syndicated credit facility to a corporation ("the Borrower"). One of the Company’s independent directors is the Chairman, President and Chief Executive Officer of the Borrower. IBERIABANK holds approximately six percent of the total commitments from twelve banks under the Credit Facility, which based on the current borrowing base, equates to $21.6 million in IBERIABANK commitments. At December 31, 2015, there was no outstanding balance to IBERIABANK under the Credit Facility. At September 30, 2016, there was approximately $20.5 million outstanding to IBERIABANK under the Credit Facility. Depending on the type of advance, IBERIABANK earns interest on its advances under the Credit Facility at the London Interbank Offered Rate (“LIBOR”) or at a rate equal to the highest of (a) the Federal Funds Rate plus 1/2 of 1%, (b) the rate of interest in effect for such day as publicly announced from time to time by Bank of America as its “prime rate”, or (c) LIBOR plus 1.00% . At September 30, 2016, the outstanding amount due IBERIABANK under the Credit Facility was on non-accrual status. Deposits from related parties held by the Company were immaterial at September 30, 2016 and December 31, 2015.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
General	General The accompanying unaudited consolidated financial statements have been prepared in accordance with 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 the Company previously filed with the SEC in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. Operating results for the period ended September 30, 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016. When we refer to the “Company,” “we,” “our,” or “us” in this Report, we mean IBERIABANK Corporation and subsidiaries (consolidated). When we refer to the “Parent,” we mean IBERIABANK Corporation. See the Glossary of Acronyms at the end of this Report for terms used throughout this Report.
Principles of Consolidation	Principles of Consolidation The Company’s consolidated financial statements include all entities in which the Company has a controlling financial interest under either the voting interest or variable interest model. The assessment of whether or not the Company has a controlling interest (i.e., the primary beneficiary) in a variable interest entity ("VIE") is performed on an on-going basis. All equity investments in non-consolidated VIEs are included in "other assets" in the Company’s consolidated balance sheets. The Company’s maximum exposure to loss as a result of its involvement with non-consolidated VIEs was approximately $130 million and $160 million at September 30, 2016 and December 31, 2015, respectively. The Company's maximum exposure to loss was equivalent to the carrying value of its investments and any related outstanding loans to the non-consolidated VIEs. Investments in entities that are not consolidated are accounted for under either the equity, cost, or proportional amortization method of accounting. Investments for which the Company has the ability to exercise significant influence over the operating and financing decisions of the entity are accounted for under the equity method. Investments for which the Company does not hold such ability are accounted for under the cost method. Investments in qualified affordable housing projects, which meet certain criteria, are accounted for under the proportional amortization method. The consolidated financial statements include the accounts of the Company and its subsidiaries, IBERIABANK; Lenders Title Company; IBERIA Capital Partners, LLC; 1887 Leasing, LLC; IBERIA Asset Management, Inc.; 840 Denning, LLC; and IBERIA CDE, LLC. All significant intercompany balances and transactions have been eliminated in consolidation.
Nature of Operations	Nature of Operations 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 IMC 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 throughout the energy industry. 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 net impact on previously reported consolidated net income, shareholders’ equity or cash flows.
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, valuation of and accounting for acquired loans, goodwill and other intangibles, income taxes, and fair value estimates.
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. Concentrations in commercial real estate have increased as a result of the Company's recent acquisitions of CRE-focused banks. 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 and guarantor support. The Company does not have any significant concentrations to any one industry or customer.
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS ASU No. 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The most significant amendment to existing GAAP is the recognition of lease assets (i.e., right of use assets) and liabilities on the balance sheet for leases that are classified as operating leases by lessees. The lessor model remains similar to the current accounting model in existing GAAP. Additional amendments include, but are not limited to, the elimination of leveraged leases; modification to the definition of a lease; amendments on sale and leaseback transactions ; and disclosure of additional quantitative and qualitative information. ASU 2016-02 will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. Lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The Company is currently evaluating the impact of the ASU on the Company’s consolidated financial statements, including whether to adopt any practical expedients or policy elections from this ASU. The Company is not expecting to early adopt the ASU. ASU No. 2016-08, No. 2016-10, and No. 2016-12 In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , to improve implementation guidance on principal versus agency considerations within Topic 606. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , to improve implementation guidance on identifying performance obligations and licensing aspects of Topic 606. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , to provide clarification on certain targeted aspects of Topic 606. The amendments in ASU No. 2016-08, No. 2016-10, and No. 2016-12 will be effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that annual reporting period. The amendments will be applied through the election of one of two retrospective methods. The Company is currently evaluating the impact of the ASUs on the Company’s consolidated financial statements. The Company is not expecting to early adopt the ASUs. ASU No. 2016-09 In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendments will require recognition of excess tax benefits and deficiencies associated with awards which vest or settle within income tax expense or benefit in the statement of comprehensive income, with the tax effects treated as discrete items in the reporting period in which they occur. The ASU further requires entities to recognize excess tax benefits regardless of whether the benefit reduces taxes payable in the current period. This will eliminate the current APIC pool concept. The amendments will also allow an accounting policy election to account for forfeitures as they occur, permit an entity to withhold up to the maximum statutory tax rates in the applicable jurisdictions while still qualifying for equity classification, and change the classification of certain cash flows associated with stock compensation. ASU 2016-09 will be effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The transition method for implementing each amendment varies. The Company expects to elect an accounting policy to account for forfeitures as they occur upon adoption. Based on the Company's current stock valuation, it does not anticipate a significant impact to the Company's consolidated financial statements at adoption. ASU No. 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . The amendments introduce an impairment model that is based on expected credit losses (“ECL”), rather than incurred losses, to estimate credit losses on certain types of financial instruments (e.g., loans and held-to-maturity securities), including certain off-balance sheet financial instruments (e.g., loan commitments). The ECL should consider historical information, current information, and reasonable and supportable forecasts, including estimates of prepayments, over the contractual term. Financial instruments with similar risk characteristics may be grouped together when estimating the ECL. The ASU also amends the current AFS security impairment model for debt securities. The new model will require an estimate of ECL when the fair value is below the amortized cost of the asset through the use of an allowance to record estimated credit losses (and subsequent recoveries). Non-credit related losses will continue to be recognized through OCI. In addition, the amendments provide for a simplified accounting model for purchased financial assets with a more-than-insignificant amount of credit deterioration since their origination. The initial estimate of expected credit losses would be recognized through an ALL with an offset (i.e., increase) to the cost basis of the related financial asset at acquisition. ASU 2016-13 will be effective for fiscal years beginning after December 15, 2019, including interim periods. The amendments will be applied through a modified-retrospective approach, resulting in a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. A prospective transition approach is required for debt securities for which OTTI had been recognized before the effective date. Amounts previously recognized in AOCI as of the date of adoption that relate to improvements in cash flows expected to be collected should continue to be accreted into income over the remaining life of the asset. Recoveries of amounts previously written off relating to improvements in cash flows after the date of adoption should be recorded in earnings when received. The Company is currently evaluating the impact of the ASU on the Company’s consolidated financial statements. ASU No. 2016-15 In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , in order to reduce current diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 will be effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The amendments should be applied using a retrospective transition method to each period presented. The Company is currently evaluating the impact of the ASU on the Company’s consolidated statement of cash flows.

Acquisition Activity (Tables)

Acquisition Activity (Tables)	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	Acquisition of Georgia Commerce Bancshares, Inc (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 103,569 Goodwill $ 86,695 Acquisition of Old Florida Bancshares, Inc. (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 152,375 Goodwill $ 100,777 Acquisition of Florida Bank Group, Inc. (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 73,043 Goodwill $ 17,442
Schedule of Assets Acquired and Liabilities Assumed	(Dollars in thousands) As Acquired 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 (5,371 ) (2) 307,531 Other real estate owned 498 (75 ) (3) 423 Core deposit intangible — 4,489 (4) 4,489 Deferred tax asset, net 18,151 8,569 (5) 26,720 Other assets 29,817 (8,949 ) (6) 20,868 Total Assets $ 541,586 $ (1,201 ) $ 540,385 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 1,898 4,618 (9) 6,516 Total Liabilities $ 453,863 $ 13,479 $ 467,342 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 values based on acquisition date 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 less costs to sell 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 adjustments 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 amount represents the adjustment of the book value of Florida Bank Group's time deposits to their estimated fair values at the date of acquisition. (8) The amount represents the adjustment of the book value of Florida Bank Group’s borrowings to their estimated fair value based on acquisition date 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. (Dollars in thousands) As Acquired Fair Value As recorded by Assets Cash and cash equivalents $ 51,059 $ — $ 51,059 Investment securities 135,710 (807 ) (1) 134,903 Loans held for sale 1,249 — 1,249 Loans 807,726 (15,607 ) (2) 792,119 Other real estate owned 9,795 (4,207 ) (3) 5,588 Core deposit intangible — 6,720 (4) 6,720 Deferred tax asset, net 3,603 5,452 (5) 9,055 Other assets 28,956 (657 ) (6) 28,299 Total Assets $ 1,038,098 $ (9,106 ) $ 1,028,992 Liabilities Interest-bearing deposits 658,133 176 (7) 658,309 Non-interest-bearing deposits 249,739 — 249,739 Borrowings 13,204 — 13,204 Other liabilities 4,171 — 4,171 Total Liabilities $ 925,247 $ 176 $ 925,423 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 acquisition date 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 less costs to sell 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 amount represents the adjustment of the book value of Georgia Commerce's time deposits to their estimated fair values at the date of acquisition. (Dollars in thousands) As Acquired 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 (10,822 ) (1) 1,062,951 Other real estate owned 4,515 1,449 (2) 5,964 Core deposit intangible — 6,821 (3) 6,821 Deferred tax asset, net 9,490 4,388 (4) 13,878 Other assets 30,549 (7,238 ) (5) 23,311 Total Assets $ 1,552,176 $ (5,402 ) $ 1,546,774 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 3,038 76 (7) 3,114 Total Liabilities $ 1,394,200 $ 199 $ 1,394,399 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 values based on acquisition date 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 less costs to sell 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 amount represents the adjustment of the book value of Old Florida's time deposits to their estimated fair values on the date of acquisition. (7) The adjustment is necessary to record Old Florida's rent liability at fair value.

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2016
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, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 217,859 $ 2,613 $ — $ 220,472 Obligations of states and political subdivisions 245,086 7,946 (127 ) 252,905 Mortgage-backed securities 2,283,336 29,475 (1,743 ) 2,311,068 Other securities 99,688 1,330 (50 ) 100,968 Total securities available for sale $ 2,845,969 $ 41,364 $ (1,920 ) $ 2,885,413 Securities held to maturity: Obligations of states and political subdivisions $ 64,898 $ 2,727 $ — $ 67,625 Mortgage-backed securities 25,755 205 (175 ) 25,785 Total securities held to maturity $ 90,653 $ 2,932 $ (175 ) $ 93,410 December 31, 2015 Amortized Cost Gross Gross (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 252,514 $ 1,161 $ (1,592 ) $ 252,083 Obligations of states and political subdivisions 182,541 5,429 (9 ) 187,961 Mortgage-backed securities 2,272,879 8,457 (16,523 ) 2,264,813 Other securities 95,496 430 (497 ) 95,429 Total securities available for sale $ 2,803,430 $ 15,477 $ (18,621 ) $ 2,800,286 Securities held to maturity: Obligations of states and political subdivisions $ 69,979 $ 2,803 $ (101 ) $ 72,681 Mortgage-backed securities 28,949 107 (776 ) 28,280 Total securities held to maturity $ 98,928 $ 2,910 $ (877 ) $ 100,961
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, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 217,859 $ 2,613 $ — $ 220,472 Obligations of states and political subdivisions 245,086 7,946 (127 ) 252,905 Mortgage-backed securities 2,283,336 29,475 (1,743 ) 2,311,068 Other securities 99,688 1,330 (50 ) 100,968 Total securities available for sale $ 2,845,969 $ 41,364 $ (1,920 ) $ 2,885,413 Securities held to maturity: Obligations of states and political subdivisions $ 64,898 $ 2,727 $ — $ 67,625 Mortgage-backed securities 25,755 205 (175 ) 25,785 Total securities held to maturity $ 90,653 $ 2,932 $ (175 ) $ 93,410 December 31, 2015 Amortized Cost Gross Gross (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ 252,514 $ 1,161 $ (1,592 ) $ 252,083 Obligations of states and political subdivisions 182,541 5,429 (9 ) 187,961 Mortgage-backed securities 2,272,879 8,457 (16,523 ) 2,264,813 Other securities 95,496 430 (497 ) 95,429 Total securities available for sale $ 2,803,430 $ 15,477 $ (18,621 ) $ 2,800,286 Securities held to maturity: Obligations of states and political subdivisions $ 69,979 $ 2,803 $ (101 ) $ 72,681 Mortgage-backed securities 28,949 107 (776 ) 28,280 Total securities held to maturity $ 98,928 $ 2,910 $ (877 ) $ 100,961
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, 2016 Less Than Twelve Months Over Twelve Months Total Gross Unrealized Losses Fair Value Gross Gross (Dollars in thousands) Securities available for sale: Obligations of state and political obligations $ (127 ) $ 30,222 $ — $ — $ (127 ) $ 30,222 Mortgage-backed securities (893 ) 236,800 (850 ) 94,259 (1,743 ) 331,059 Other securities (1 ) 507 (49 ) 3,916 (50 ) 4,423 Total securities available for sale $ (1,021 ) $ 267,529 $ (899 ) $ 98,175 $ (1,920 ) $ 365,704 Securities held to maturity: Obligations of states and political subdivisions $ — $ 2,212 $ — $ — $ — $ 2,212 Mortgage-backed securities — — (175 ) 11,698 (175 ) 11,698 Total securities held to maturity $ — $ 2,212 $ (175 ) $ 11,698 $ (175 ) $ 13,910 December 31, 2015 Less Than Twelve Months Over Twelve Months Total Gross Gross Gross (Dollars in thousands) Securities available for sale: U.S. Government-sponsored enterprise obligations $ (1,214 ) $ 177,839 $ (378 ) $ 28,116 $ (1,592 ) $ 205,955 Obligations of states and political subdivisions (9 ) 5,765 — — (9 ) 5,765 Mortgage-backed securities (11,737 ) 1,279,914 (4,786 ) 185,215 (16,523 ) 1,465,129 Other securities (488 ) 51,975 (9 ) 499 (497 ) 52,474 Total securities available for sale $ (13,448 ) $ 1,515,493 $ (5,173 ) $ 213,830 $ (18,621 ) $ 1,729,323 Securities held to maturity: Obligations of states and political subdivisions $ (9 ) $ 1,999 $ (92 ) $ 4,162 $ (101 ) $ 6,161 Mortgage-backed securities (45 ) 3,530 (731 ) 17,573 (776 ) 21,103 Total securities held to maturity $ (54 ) $ 5,529 $ (823 ) $ 21,735 $ (877 ) $ 27,264
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, 2016 and December 31, 2015 is presented in the following table. (Dollars in thousands) September 30, 2016 December 31, 2015 Number of securities Issued by Fannie Mae, Freddie Mac, or Ginnie Mae 27 40 Issued by political subdivisions — 2 Other 3 1 30 43 Amortized cost basis Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 106,982 $ 236,800 Issued by political subdivisions — 4,253 Other 3,965 508 $ 110,947 $ 241,561 Unrealized loss Issued by Fannie Mae, Freddie Mac, or Ginnie Mae $ 1,025 $ 5,895 Issued by political subdivisions — 92 Other 49 9 $ 1,074 $ 5,996
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, 2016 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 2.36 % $ 19,560 $ 19,658 2.42 % $ 2,059 $ 2,076 One through five years 1.64 % 275,596 279,271 2.97 % 10,295 10,583 After five through ten years 2.29 % 585,382 602,194 3.07 % 18,357 19,214 Over ten years 1.97 % 1,965,431 1,984,290 2.74 % 59,942 61,537 2.01 % $ 2,845,969 $ 2,885,413 2.82 % $ 90,653 $ 93,410
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) 2016 2015 2016 2015 Realized gains $ 12 $ 425 $ 2,947 $ 1,786 Realized losses — (145 ) (950 ) (217 ) $ 12 $ 280 $ 1,997 $ 1,569
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, 2016 December 31, 2015 Federal Home Loan Bank (FHLB) stock $ 47,589 $ 16,265 Federal Reserve Bank (FRB) stock 48,584 48,584 Other investments 1,159 1,159 $ 97,332 $ 66,008

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Schedule of Non-Covered and Covered Loans	Loans consist of the following, segregated into legacy and acquired loans, for the periods indicated: September 30, 2016 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Real estate $ 5,419,483 $ 1,261,732 $ 6,681,215 Commercial and industrial 3,101,472 361,525 3,462,997 Energy-related 598,279 1,362 599,641 9,119,234 1,624,619 10,743,853 Residential mortgage loans: 840,082 430,448 1,270,530 Consumer and other loans: Home equity 1,755,295 395,835 2,151,130 Indirect automobile 153,904 9 153,913 Other 544,855 60,218 605,073 2,454,054 456,062 2,910,116 Total $ 12,413,370 $ 2,511,129 $ 14,924,499 December 31, 2015 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Real estate $ 4,504,062 $ 1,569,449 $ 6,073,511 Commercial and industrial 2,952,102 492,476 3,444,578 Energy-related 677,177 3,589 680,766 8,133,341 2,065,514 10,198,855 Residential mortgage loans: 694,023 501,296 1,195,319 Consumer and other loans: Home equity 1,575,643 490,524 2,066,167 Indirect automobile 246,214 84 246,298 Other 541,299 79,490 620,789 2,363,156 570,098 2,933,254 Total $ 11,190,520 $ 3,136,908 $ 14,327,428
Schedule of Aging of Non-Covered Loans	The following tables provide an analysis of the aging of loans as of September 30, 2016 and December 31, 2015 . Due to the difference in accounting for acquired loans, the tables below further segregate the Company’s loans between loans originated by the Company (“legacy loans”) and acquired loans. September 30, 2016 Legacy loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due Non-accrual Loans Total Loans Commercial real estate - Construction $ 694,868 $ — $ — $ 1,234 $ 1,234 $ 25 $ 696,127 Commercial real estate - Other 4,704,088 1,514 445 2,389 4,348 14,920 4,723,356 Commercial and industrial 3,050,241 14,713 1,404 148 16,265 34,966 3,101,472 Energy-related 444,659 — — — — 153,620 598,279 Residential mortgage 817,154 1,396 7,389 327 9,112 13,816 840,082 Consumer - Home equity 1,740,001 6,207 1,968 101 8,276 7,018 1,755,295 Consumer - Indirect automobile 150,008 2,151 405 — 2,556 1,340 153,904 Consumer - Credit card 79,588 311 115 — 426 438 80,452 Consumer - Other 459,548 2,145 994 737 3,876 979 464,403 Total $ 12,140,155 $ 28,437 $ 12,720 $ 4,936 $ 46,093 $ 227,122 $ 12,413,370 December 31, 2015 Legacy loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due Non-accrual Loans Total Loans Commercial real estate - Construction $ 635,560 $ 801 $ — $ — $ 801 $ 120 $ 636,481 Commercial real estate - Other 3,848,584 2,687 793 95 3,575 15,422 3,867,581 Commercial and industrial 2,943,409 1,208 739 87 2,034 6,659 2,952,102 Energy-related 670,081 15 — — 15 7,081 677,177 Residential mortgage 676,347 1,075 2,485 442 4,002 13,674 694,023 Consumer - Home equity 1,565,596 3,549 870 — 4,419 5,628 1,575,643 Consumer - Indirect automobile 242,328 2,187 518 — 2,705 1,181 246,214 Consumer - Credit card 76,360 394 113 — 507 394 77,261 Consumer - Other 460,594 1,923 752 — 2,675 769 464,038 Total $ 11,118,859 $ 13,839 $ 6,270 $ 624 $ 20,733 $ 50,928 $ 11,190,520 September 30, 2016 Acquired loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due (1) (2) Non-accrual Loans Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - Construction $ 41,618 $ — $ — $ — $ — $ 1,946 $ (285 ) $ 37,516 $ 80,795 Commercial real estate - Other 913,519 — 387 — 387 1,976 (4,991 ) 270,046 1,180,937 Commercial and industrial 324,496 561 249 — 810 1,770 (705 ) 35,154 361,525 Energy-related 1,369 — — — — — (7 ) — 1,362 Residential mortgage 307,677 — 1,339 280 1,619 1,258 (5,855 ) 125,749 430,448 Consumer - Home equity 301,164 419 289 17 725 1,206 (1,762 ) 94,502 395,835 Consumer - Indirect automobile 9 — — — — — — — 9 Consumer - Credit Card — — — — — — — 507 507 Consumer - Other 57,929 521 203 — 724 243 (4,758 ) 5,573 59,711 Total $ 1,947,781 $ 1,501 $ 2,467 $ 297 $ 4,265 $ 8,399 $ (18,363 ) $ 569,047 $ 2,511,129 December 31, 2015 Acquired loans Accruing (Dollars in thousands) Current or Less Than 30 days past due 30-59 days 60-89 days > 90 days Total Past Due (1) (2) Non-accrual Loans Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - Construction $ 69,167 $ 180 $ 117 $ — $ 297 $ — $ (358 ) $ 56,320 $ 125,426 Commercial real estate - Other 1,090,688 861 705 — 1,566 1,491 (4,479 ) 354,757 1,444,023 Commercial and industrial 442,454 623 — — 623 1,154 (2,517 ) 50,762 492,476 Energy-related 2,186 — — — — 170 2 1,231 3,589 Residential mortgage 365,261 7 940 — 947 1,109 (6,601 ) 140,580 501,296 Consumer - Home equity 381,107 622 416 291 1,329 1,291 (7,333 ) 114,130 490,524 Consumer - Indirect automobile 19 — — — — — — 65 84 Consumer - Credit Card — — — — — — — 582 582 Consumer - Other 74,385 468 127 — 595 206 (2,570 ) 6,292 78,908 Total $ 2,425,267 $ 2,761 $ 2,305 $ 291 $ 5,357 $ 5,421 $ (23,856 ) $ 724,719 $ 3,136,908 (1) Past due information presents acquired loans at the gross loan balance, prior to application of discounts. (2) Past due loan amounts exclude acquired impaired loans, even if contractually past due or if the Company does not expect to receive payment in full, as the Company is currently accreting interest income over the expected life of the loans.
Schedule of Carrying Amount of Loan Acquired	The tables below show the balances acquired during 2015 for these two subsections of the portfolio as of the acquisition date. (Dollars in thousands) Acquired Non-Impaired Loans Contractually required principal and interest at acquisition $ 2,384,114 Expected losses and foregone interest (15,539 ) Cash flows expected to be collected at acquisition 2,368,575 Fair value of acquired loans at acquisition $ 2,105,466 (Dollars in thousands) Acquired Impaired Loans Contractually required principal and interest at acquisition $ 76,445 Non-accretable difference (expected losses and foregone interest) (11,867 ) Cash flows expected to be collected at acquisition 64,578 Accretable yield (6,823 ) Basis in acquired loans at acquisition $ 57,755
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: (Dollars in thousands) 2016 2015 Balance at beginning of period $ 227,502 $ 287,651 Acquisition — 4,592 Transfers from non-accretable difference to accretable yield 5,491 7,199 Accretion (52,603 ) (60,305 ) Changes in expected cash flows not affecting non-accretable differences (1) 12,743 (1,511 ) Balance at end of period $ 193,133 $ 237,626 (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.
Schedule of Modified TDRs	The following table provides information on how the TDRs were modified during the nine months ended September 30: (Dollars in thousands) 2016 2015 Extended maturities $ 76,059 $ 15,932 Maturity and interest rate adjustment 26,372 23,552 Forbearance 75,953 1,228 Movement to or extension of interest-rate only payments 1,689 — Interest rate adjustment 133 — Other concession(s) (1) 38,390 7,887 Total $ 218,596 $ 48,599 (1) Other concessions may include covenant waivers, forgiveness of principal or interest associated with a customer bankruptcy, or a combination of any of the above concessions.
Schedule of Subsequently Defaulted TDRs	The following table presents the end of period balance for loans modified in a TDR during the nine-month periods ended September 30: 2016 2015 (In thousands, except number of loans) Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Commercial real estate 23 $ 22,765 $ 16,441 8 $ 26,408 $ 25,572 Commercial and industrial 49 44,144 43,083 18 19,798 19,643 Energy-related 28 143,012 145,298 1 3,434 3,384 Residential mortgage 31 4,784 4,659 — — — Consumer - Home Equity 104 7,071 6,805 — — — Consumer - Other 142 2,372 2,310 — — — Total 377 $ 224,148 $ 218,596 27 $ 49,640 $ 48,599 Information detailing TDRs which defaulted during the nine-month periods ended September 30, 2016 and 2015 , and 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, 2016 September 30, 2015 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate 5 $ 668 4 $ 12,939 Commercial and industrial 21 7,476 15 13,145 Energy-related 1 1,394 1 3,384 Residential mortgage 5 364 — — Consumer - Home Equity 16 1,037 — — Consumer - Other 13 278 — — Total 61 $ 11,217 20 $ 29,468

Allowance for Credit Losses a30

Allowance for Credit Losses and Credit Quality (Tables)	9 Months Ended
	Sep. 30, 2016
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 nine months ended September 30 is as follows: 2016 (Dollars in thousands) Legacy Loans Acquired Loans Total Allowance for credit losses Allowance for loan losses at beginning of period $ 93,808 $ 44,570 $ 138,378 Provision for (Reversal of) loan losses before benefit attributable to FDIC loss share agreements 40,516 (2,501 ) 38,015 Adjustment attributable to FDIC loss share arrangements — 1,240 1,240 Net provision for loan losses 40,516 (1,261 ) 39,255 Adjustment attributable to FDIC loss share arrangements — (1,240 ) (1,240 ) Transfer of balance to OREO and other — (2,045 ) (2,045 ) Loans charged-off (28,559 ) (1,495 ) (30,054 ) Recoveries 3,124 775 3,899 Allowance for loan losses at end of period $ 108,889 $ 39,304 $ 148,193 Reserve for unfunded commitments at beginning of period 14,145 — 14,145 Provision for (Reversal of) unfunded lending commitments (2,155 ) — (2,155 ) Reserve for unfunded commitments at end of period $ 11,990 $ — $ 11,990 Allowance for credit losses at end of period $ 120,879 $ 39,304 $ 160,183 2015 (Dollars in thousands) Legacy Loans Acquired Loans Total Allowance for credit losses Allowance for loan losses at beginning of period $ 76,174 $ 53,957 $ 130,131 Provision for loan losses before benefit attributable to FDIC loss share agreements 17,743 112 17,855 Adjustment attributable to FDIC loss share arrangements — 1,342 1,342 Net provision for loan losses 17,743 1,454 19,197 Adjustment attributable to FDIC loss share arrangements — (1,342 ) (1,342 ) Transfer of balance to OREO and other — (9,768 ) (9,768 ) Loans charged-off (12,073 ) (952 ) (13,025 ) Recoveries 4,556 505 5,061 Allowance for loan losses at end of period $ 86,400 $ 43,854 $ 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 $ 43,854 $ 144,779 A summary of changes in the allowance for credit losses for legacy loans, by loan portfolio type, for the nine months ended September 30 is as follows: 2016 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loan losses at beginning of period $ 24,658 $ 23,283 $ 23,863 $ 3,947 $ 18,057 $ 93,808 Provision for (Reversal of) loan losses (651 ) 13,201 18,998 248 8,720 40,516 Loans charged off (1,598 ) (2,418 ) (14,672 ) (240 ) (9,631 ) (28,559 ) Recoveries 766 251 — 142 1,965 3,124 Allowance for loan losses at end of period $ 23,175 $ 34,317 $ 28,189 $ 4,097 $ 19,111 $ 108,889 Reserve for unfunded commitments at beginning of period $ 4,160 $ 3,448 $ 2,665 $ 830 $ 3,042 $ 14,145 Provision for (Reversal of) unfunded commitments (427 ) (46 ) (1,712 ) (148 ) 178 (2,155 ) Reserve for unfunded commitments at end of period $ 3,733 $ 3,402 $ 953 $ 682 $ 3,220 $ 11,990 Allowance on loans individually evaluated for impairment $ 655 $ 8,996 $ 14,396 $ 110 $ 1,053 $ 25,210 Allowance on loans collectively evaluated for impairment 22,520 25,321 13,793 3,987 18,058 83,679 Loans, net of unearned income: Balance at end of period $ 5,419,483 $ 3,101,472 $ 598,279 $ 840,082 $ 2,454,054 $ 12,413,370 Balance at end of period individually evaluated for impairment 31,405 58,464 212,512 4,539 11,546 318,466 Balance at end of period collectively evaluated for impairment 5,388,078 3,043,008 385,767 835,543 2,442,508 12,094,904 2015 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loan losses at beginning of period $ 26,752 $ 24,455 $ 5,949 $ 2,678 $ 16,340 $ 76,174 Provision for (Reversal of) loan losses (947 ) 1,308 9,269 1,474 6,639 17,743 Loans charged off (2,009 ) (1,048 ) — (224 ) (8,792 ) (12,073 ) Recoveries 1,535 49 — 44 2,928 4,556 Allowance for loan losses at end of period $ 25,331 $ 24,764 $ 15,218 $ 3,972 $ 17,115 $ 86,400 Reserve for unfunded commitments at beginning of period $ 3,370 $ 3,733 $ 1,596 $ 168 $ 2,934 $ 11,801 Provision for (Reversal of) unfunded commitments 218 (149 ) 2,037 650 (32 ) 2,724 Reserve for unfunded commitments at end of period $ 3,588 $ 3,584 $ 3,633 $ 818 $ 2,902 $ 14,525 Allowance on loans individually evaluated for impairment $ 883 $ 817 $ — $ — $ — $ 1,700 Allowance on loans collectively evaluated for impairment 24,448 23,947 15,218 3,972 17,115 84,700 Loans, net of unearned income: Balance at end of period $ 4,321,723 $ 2,779,503 $ 713,935 $ 660,543 $ 2,303,554 $ 10,779,258 Balance at end of period individually evaluated for impairment 26,463 22,076 3,409 — 198 52,146 Balance at end of period collectively evaluated for impairment 4,295,260 2,757,427 710,526 660,543 2,303,356 10,727,112 A summary of changes in the allowance for credit losses for acquired loans, by loan portfolio type, for the nine months ended September 30 is as follows: 2016 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loan losses at beginning of period $ 25,979 $ 2,819 $ 125 $ 7,841 $ 7,806 $ 44,570 Provision for (Reversal of) loan losses (1,952 ) 216 (99 ) 1,017 (443 ) (1,261 ) Decrease in FDIC loss share receivable (34 ) (50 ) — (833 ) (323 ) (1,240 ) Transfer of balance to OREO and other (380 ) (467 ) — 28 (1,226 ) (2,045 ) Loans charged off (789 ) — — — (706 ) (1,495 ) Recoveries 102 217 — 33 423 775 Allowance for loan losses at end of period $ 22,926 $ 2,735 $ 26 $ 8,086 $ 5,531 $ 39,304 Allowance on loans individually evaluated for impairment $ 177 $ 77 $ — $ — $ — $ 254 Allowance on loans collectively evaluated for impairment 22,749 2,658 26 8,086 5,531 39,050 Loans, net of unearned income: Balance at end of period $ 1,261,732 $ 361,525 $ 1,362 $ 430,448 $ 456,062 $ 2,511,129 Balance at end of period individually evaluated for impairment 5,647 1,926 — — 679 8,252 Balance at end of period collectively evaluated for impairment 948,523 324,445 1,362 304,699 354,801 1,933,830 Balance at end of period acquired with deteriorated credit quality 307,562 35,154 — 125,749 100,582 569,047 2015 Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage (Dollars in thousands) Consumer Total Allowance for loans losses at beginning of period $ 29,949 $ 3,265 $ 51 $ 6,484 $ 14,208 $ 53,957 Provision for (Reversal of) loan losses 809 174 67 1,263 (859 ) 1,454 (Decrease) Increase in FDIC loss share receivable 748 59 — (277 ) (1,872 ) (1,342 ) Transfer of balance to OREO and other (6,096 ) (282 ) — (472 ) (2,918 ) (9,768 ) Loans charged off — (8 ) — (59 ) (885 ) (952 ) Recoveries 8 116 — 4 377 505 Allowance for loans losses at end of period $ 25,418 $ 3,324 $ 118 $ 6,943 $ 8,051 $ 43,854 Allowance on loans individually evaluated for impairment $ — $ — $ — $ — $ 16 $ 16 Allowance on loans collectively evaluated for impairment 25,418 3,324 118 6,943 8,035 43,838 Loans, net of unearned income: Balance at end of period $ 1,658,028 $ 523,468 $ 5,521 $ 529,398 $ 621,346 $ 3,337,761 Balance at end of period individually evaluated for impairment — 142 — — 456 598 Balance at end of period collectively evaluated for impairment 1,205,439 465,514 5,521 385,854 493,032 2,555,360 Balance at end of period acquired with deteriorated credit quality 452,589 57,812 — 143,544 127,858 781,803
Investment in Covered Loans and Non-Covered Loans by Credit Quality Indicator	The Company’s investment in loans by credit quality indicator is presented in the following tables. The tables below further segregate the Company’s loans between loans that were originated by the Company (legacy loans) and acquired loans. 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, 2016 and December 31, 2015 . 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, 2016 and December 31, 2015 . Loan delinquency is the primary credit quality indicator that the Company utilizes to monitor consumer asset quality. Legacy loans September 30, 2016 December 31, 2015 (Dollars in thousands) Pass Special Mention Sub-standard Doubtful Loss Total Pass Special Mention Sub-standard Doubtful Loss Total Commercial real estate - Construction $ 694,983 $ 84 $ 1,060 $ — $ — $ 696,127 $ 634,889 $ 160 $ 1,432 $ — $ — $ 636,481 Commercial real estate - Other 4,654,619 22,919 45,656 162 — 4,723,356 3,806,528 21,877 37,001 2,175 — 3,867,581 Commercial and industrial 2,994,661 34,249 53,951 18,611 — 3,101,472 2,911,396 14,826 19,888 5,992 — 2,952,102 Energy-related 279,404 65,263 249,640 3,972 — 598,279 531,657 67,937 74,272 3,311 — 677,177 Total $ 8,623,667 $ 122,515 $ 350,307 $ 22,745 $ — $ 9,119,234 $ 7,884,470 $ 104,800 $ 132,593 $ 11,478 $ — $ 8,133,341 Legacy loans September 30, 2016 December 31, 2015 (Dollars in thousands) Current 30+ Days Past Due Total Current 30+ Days Past Due Total Residential mortgage $ 817,154 $ 22,928 $ 840,082 $ 676,347 $ 17,676 $ 694,023 Consumer - Home equity 1,740,001 15,294 1,755,295 1,565,596 10,047 1,575,643 Consumer - Indirect automobile 150,008 3,896 153,904 242,328 3,886 246,214 Consumer - Credit card 79,588 864 80,452 76,360 901 77,261 Consumer - Other 459,548 4,855 464,403 460,594 3,444 464,038 Total $ 3,246,299 $ 47,837 $ 3,294,136 $ 3,021,225 $ 35,954 $ 3,057,179 Acquired loans September 30, 2016 December 31, 2015 (Dollars in thousands) Pass Special Mention Sub- standard Doubtful Loss Premium/(Discount) Total Pass Special Mention Sub- standard Doubtful Loss Premium/(Discount) Total Commercial real estate-Construction $ 63,139 $ 140 $ 5,167 $ 744 $ — $ 11,605 $ 80,795 $ 104,064 $ 1,681 $ 8,803 $ 771 $ — $ 10,107 $ 125,426 Commercial real estate - Other 1,145,942 21,731 46,941 1,484 23 (35,184 ) 1,180,937 1,395,884 26,080 79,119 6,124 111 (63,295 ) 1,444,023 Commercial and industrial 361,376 6,216 14,443 558 — (21,068 ) 361,525 473,241 8,376 16,510 1,206 43 (6,900 ) 492,476 Energy-related 1,369 — — — — (7 ) 1,362 2,166 55 170 1,198 — — 3,589 Total $ 1,571,826 $ 28,087 $ 66,551 $ 2,786 $ 23 $ (44,654 ) $ 1,624,619 $ 1,975,355 $ 36,192 $ 104,602 $ 9,299 $ 154 $ (60,088 ) $ 2,065,514 Acquired loans September 30, 2016 December 31, 2015 (Dollars in thousands) Current 30+ Days Past Due Premium (Discount) Total Current 30+ Days Past Due Premium (Discount) Total Residential mortgage $ 441,411 $ 21,832 $ (32,795 ) $ 430,448 $ 506,103 $ 24,752 $ (29,559 ) $ 501,296 Consumer - Home equity 408,541 11,458 (24,164 ) 395,835 503,635 16,381 (29,492 ) 490,524 Consumer - Indirect automobile 9 1 (1 ) 9 72 12 — 84 Consumer - Other 58,998 1,618 (398 ) 60,218 79,732 1,475 (1,717 ) 79,490 Total $ 908,959 $ 34,909 $ (57,358 ) $ 886,510 $ 1,089,542 $ 42,620 $ (60,768 ) $ 1,071,394
Schedule of Investment in Legacy Impaired Loan	Information on the Company’s investment in legacy impaired loans, which include all TDRs and all other non-accrual loans, is presented in the following tables as of and for the periods indicated. Legacy non-accrual mortgage and consumer loans, and commercial loans below the Company's specific threshold, are included for purposes of this disclosure although such loans are generally not evaluated or measured individually for impairment for purposes of determining the allowance for loan losses. September 30, 2016 December 31, 2015 Unpaid Principal Balance Recorded Investment Related Allowance Unpaid Principal Balance Recorded Investment Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 15,447 $ 14,655 $ — $ 17,002 $ 16,145 $ — Commercial business 29,162 28,722 — 14,571 14,340 — Energy-related 168,723 163,156 — — — — Residential mortgage — — — — — — Consumer - Home equity — — — 730 730 — Consumer -Other — — — 66 66 — With an allowance recorded: Commercial real estate 17,870 17,843 (660 ) 21,377 13,753 (1,253 ) Commercial and industrial 31,406 31,067 (9,012 ) 7,422 6,262 (277 ) Energy-related 52,749 49,407 (14,396 ) 13,474 13,444 (2,125 ) Residential mortgage 18,205 16,840 (124 ) 14,806 13,743 (64 ) Consumer - Home equity 16,845 15,615 (855 ) 9,486 8,559 (363 ) Consumer - Indirect automobile 2,465 1,727 (128 ) 1,955 1,181 (10 ) Consumer - Credit card 438 438 (9 ) 394 394 (8 ) Consumer - Other 2,711 2,573 (122 ) 1,450 899 (23 ) Total $ 356,021 $ 342,043 $ (25,306 ) $ 102,733 $ 89,516 $ (4,123 ) Total commercial loans $ 315,357 $ 304,850 $ (24,068 ) $ 73,846 $ 63,944 $ (3,655 ) Total mortgage loans 18,205 16,840 (124 ) 14,806 13,743 (64 ) Total consumer loans 22,459 20,353 (1,114 ) 14,081 11,829 (404 ) 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 Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded: Commercial real estate $ 20,345 $ 220 $ 16,018 $ 37 $ 20,633 $ 663 $ 16,036 $ 79 Commercial and industrial 29,533 313 20,055 159 30,772 1,030 20,630 465 Energy-related 165,459 1,364 3,409 — 149,099 3,755 3,425 — Residential mortgage — — — — — — — — Consumer - Home equity — — 215 3 — — 204 4 With an allowance recorded: Commercial real estate 17,776 143 11,649 128 17,654 433 8,247 385 Commercial and industrial 31,859 366 2,121 — 39,087 1,211 2,634 — Energy-related 55,947 416 99 — 42,089 1,325 106 — Residential mortgage 16,558 49 15,008 — 16,410 177 15,100 — Consumer - Home equity 14,632 119 5,344 — 13,696 348 5,462 — Consumer - Indirect automobile 1,853 16 1,361 — 2,092 70 1,551 — Consumer - Credit card 468 — 721 — 461 — 1,038 — Consumer - Other 2,346 38 1,030 — 2,065 109 1,068 — Total $ 356,776 $ 3,044 $ 77,030 $ 327 334,058 9,121 $ 75,501 $ 933 Total commercial loans $ 320,919 $ 2,822 $ 53,351 $ 324 $ 299,334 $ 8,417 $ 51,078 $ 929 Total mortgage loans 16,558 49 15,008 — 16,410 177 15,100 — Total consumer loans 19,299 173 8,671 3 18,314 527 9,323 4

Loss Sharing Agreements and F31

Loss Sharing Agreements and FDIC Loss Share Receivable (Tables)	9 Months Ended
	Sep. 30, 2016
Loss Sharing Agreements and FDIC Loss Share Receivable [Abstract]
Schedule of FDIC Loss Share Receivables	The following is a summary of the year-to-date activity for the FDIC loss share receivables: Nine Months Ended September 30, (Dollars in thousands) 2016 2015 Balance at beginning of period $ 39,878 $ 69,627 Reversal of loan loss provision recorded on FDIC covered loans (1,240 ) (1,342 ) Amortization (12,484 ) (19,011 ) Submission of reimbursable losses to the FDIC (1,760 ) (4,084 ) Changes in cash flow assumptions on OREO and other adjustments 12 (1,747 ) Balance at end of period $ 24,406 $ 43,443

Goodwill and Other Intangible32

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2016
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, 2016, and the year ended December 31, 2015 are provided in the following table. (Dollars in thousands) IBERIABANK IMC LTC Total Balance, December 31, 2014 $ 489,183 $ 23,178 $ 5,165 $ 517,526 Goodwill acquired during the year 207,077 — — 207,077 Balance, December 31, 2015 $ 696,260 $ 23,178 $ 5,165 $ 724,603 Goodwill adjustments during the period 2,253 — — 2,253 Balance, September 30, 2016 $ 698,513 $ 23,178 $ 5,165 $ 726,856
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, 2016 December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Core deposit intangibles $ 74,001 $ (50,128 ) $ 23,873 $ 74,001 $ (43,957 ) $ 30,044 Customer relationship intangible asset 1,348 (1,013 ) 335 1,348 (984 ) 364 Non-compete agreement 62 (18 ) 44 100 (79 ) 21 Other intangible assets — — — 205 (114 ) 91 Total $ 75,411 $ (51,159 ) $ 24,252 $ 75,654 $ (45,134 ) $ 30,520 Mortgage servicing rights had the following carrying values as of the periods indicated: September 30, 2016 December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Mortgage servicing rights $ 6,295 $ (2,945 ) $ 3,350 $ 6,104 $ (2,320 ) $ 3,784

Derivative Instruments and Ot33

Derivative Instruments and Other Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Derivative Instruments	Information pertaining to outstanding derivative instruments is as follows: Asset Derivatives Fair Value Liability Derivatives Fair Value (Dollars in thousands) Balance September 30, 2016 December 31, 2015 Balance September 30, 2016 December 31, 2015 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts Other $ — $ 58 Other $ 9,649 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ 58 $ 9,649 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts Other $ 39,438 $ 18,077 Other $ 39,563 $ 18,077 Foreign exchange contracts Other 44 156 Other 30 134 Forward sales contracts Other 105 1,588 Other 1,680 474 Written and purchased options Other 16,217 10,607 Other 8,017 6,254 Total derivatives not designated as hedging instruments under ASC Topic 815 55,804 30,428 49,290 24,939 Total $ 55,804 $ 30,486 $ 58,939 $ 24,939 Asset Derivatives Liability Derivatives (Dollars in thousands) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts $ — $ 108,500 $ 108,500 $ — Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ 108,500 $ 108,500 $ — Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts $ 976,456 $ 590,334 $ 976,456 $ 590,334 Foreign exchange contracts 4,644 4,392 4,644 4,392 Forward sales contracts 53,662 223,841 405,697 173,430 Written and purchased options 400,129 328,210 167,211 181,949 Total derivatives not designated as hedging instruments under ASC Topic 815 1,434,891 1,146,777 1,554,008 950,105 Total $ 1,434,891 $ 1,255,277 $ 1,662,508 $ 950,105
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, 2016 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 39,438 $ — $ — $ 39,438 Written and purchased options 7,998 — — 7,998 Total derivative assets subject to master netting arrangements $ 47,436 $ — $ — $ 47,436 Derivative liabilities Interest rate contracts designated as hedging instruments $ 9,649 $ — $ (12,752 ) $ (3,103 ) Interest rate contracts not designated as hedging instruments 39,563 — (45,247 ) (5,684 ) Total derivative liabilities subject to master netting arrangements $ 49,212 $ — $ (57,999 ) $ (8,787 ) (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. December 31, 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 $ 58 $ — $ — $ 58 Interest rate contracts not designated as hedging instruments 18,058 — — 18,058 Written and purchased options 6,277 — — 6,277 Total derivative assets subject to master netting arrangements $ 24,393 $ — $ — $ 24,393 Derivative liabilities Interest rate contracts not designated as hedging instruments $ 18,058 $ — $ (20,104 ) $ (2,046 ) Total derivative liabilities subject to master netting arrangements $ 18,058 $ — $ (20,104 ) $ (2,046 ) (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, 2016 Gross Amounts Gross Amounts Not Offset (Dollars in thousands) Derivatives Collateral (1) Net Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 39,438 $ — $ — $ 39,438 Written and purchased options 7,998 — — 7,998 Total derivative assets subject to master netting arrangements $ 47,436 $ — $ — $ 47,436 Derivative liabilities Interest rate contracts designated as hedging instruments $ 9,649 $ — $ (12,752 ) $ (3,103 ) Interest rate contracts not designated as hedging instruments 39,563 — (45,247 ) (5,684 ) Total derivative liabilities subject to master netting arrangements $ 49,212 $ — $ (57,999 ) $ (8,787 ) (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. December 31, 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 $ 58 $ — $ — $ 58 Interest rate contracts not designated as hedging instruments 18,058 — — 18,058 Written and purchased options 6,277 — — 6,277 Total derivative assets subject to master netting arrangements $ 24,393 $ — $ — $ 24,393 Derivative liabilities Interest rate contracts not designated as hedging instruments $ 18,058 $ — $ (20,104 ) $ (2,046 ) Total derivative liabilities subject to master netting arrangements $ 18,058 $ — $ (20,104 ) $ (2,046 ) (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, 2016 and 2015, 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 2016 2015 2016 2015 2016 2015 Interest rate contracts $ 146 $ (3,412 ) Other income (expense) $ — $ — Other income (expense) $ — $ — Total $ 146 $ (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 2016 2015 2016 2015 2016 2015 Interest rate contracts $ (6,309 ) $ (374 ) Other income (expense) $ — $ — Other income (expense) $ — $ — Total $ (6,309 ) $ (374 ) $ — $ — $ — $ — Information pertaining to the effect of derivatives not designated as hedging instruments on the consolidated financial statements is as follows: Amount of Gain (Loss) Recognized Location of Gain (Loss) For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2016 2015 2016 2015 Interest rate contracts (1) Other income $ 2,215 $ 1,130 $ 7,509 $ 3,069 Foreign exchange contracts Other income 4 — 7 — Forward sales contracts Mortgage income (2,590 ) (6,524 ) (12,720 ) 1,526 Written and purchased options Mortgage income (2,624 ) (526 ) 3,846 (1,711 ) Total $ (2,995 ) $ (5,920 ) $ (1,358 ) $ 2,884 (1) Includes fees associated with customer interest rate contracts.

Shareholders' Equity, Capital34

Shareholders' Equity, Capital Ratios and Other Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2016
Banking and Thrift [Abstract]
Actual Capital Amounts and Ratios	The Company’s and IBERIABANK’s actual capital amounts and ratios as of September 30, 2016 and December 31, 2015 are presented in the following table. September 30, 2016 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 784,103 4.00 % N/A N/A $ 1,901,866 9.70 % IBERIABANK 781,582 4.00 976,978 5.00 1,831,469 9.37 Common Equity Tier 1 (CET1) Consolidated $ 785,140 4.50 % N/A N/A $ 1,769,769 10.14 % IBERIABANK 783,333 4.50 1,131,481 6.50 1,831,469 10.52 Tier 1 Risk-Based Capital Consolidated $ 1,046,854 6.00 % N/A N/A $ 1,901,866 10.90 % IBERIABANK 1,044,444 6.00 1,392,591 8.00 1,831,469 10.52 Total Risk-Based Capital Consolidated $ 1,395,805 8.00 % N/A N/A $ 2,178,549 12.49 % IBERIABANK 1,392,591 8.00 1,740,739 10.00 1,991,651 11.44 December 31, 2015 Minimum Well Capitalized Actual (Dollars in thousands) Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 751,798 4.00 % N/A N/A $ 1,790,034 9.52 % IBERIABANK 749,226 4.00 936,532 5.00 1,691,022 9.03 Common Equity Tier 1 (CET1) Consolidated $ 752,610 4.50 % N/A N/A $ 1,684,097 10.07 % IBERIABANK 750,660 4.50 1,084,287 6.50 1,691,022 10.14 Tier 1 Risk-Based Capital Consolidated $ 1,003,479 6.00 % N/A N/A $ 1,790,034 10.70 % IBERIABANK 1,000,880 6.00 1,334,507 8.00 1,691,022 10.14 Total Risk-Based Capital Consolidated $ 1,337,973 8.00 % N/A N/A $ 2,029,932 12.14 % IBERIABANK 1,334,507 8.00 1,668,133 10.00 1,843,545 11.05

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2016
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) 2016 2015 2016 2015 Earnings per common share - basic Net income $ 48,068 $ 42,475 $ 141,647 $ 98,437 Preferred stock dividends (3,590 ) — (7,020 ) — Dividends and undistributed earnings allocated to unvested restricted shares (462 ) (492 ) (1,464 ) (1,171 ) Earnings allocated to common shareholders - basic $ 44,016 $ 41,983 $ 133,163 $ 97,266 Weighted average common shares outstanding 40,618 40,514 40,699 37,436 Earnings per common share - basic $ 1.08 $ 1.04 $ 3.27 $ 2.60 Earnings per common share - diluted Earnings allocated to common shareholders - basic $ 44,016 $ 41,983 $ 133,163 $ 97,266 Dividends and undistributed earnings allocated to unvested restricted shares (4 ) (3 ) (17 ) (41 ) Earnings allocated to common shareholders - diluted $ 44,012 $ 41,980 $ 133,146 $ 97,225 Weighted average common shares outstanding 40,618 40,514 40,699 37,436 Dilutive potential common shares - stock options 193 100 119 96 Weighted average common shares outstanding - diluted 40,811 40,614 40,818 37,532 Earnings per common share - diluted $ 1.08 $ 1.03 $ 3.26 $ 2.59

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2016
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, 2015 813,777 $ 56.99 Granted 152,209 47.63 Exercised (72,258 ) 55.28 Forfeited or expired (49,636 ) 60.06 Outstanding options, September 30, 2016 844,092 $ 55.27 Exercisable options, September 30, 2016 538,751 $ 56.40 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
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 following periods: For the Nine Months Ended September 30 2016 2015 Expected dividends 2.9 % 2.2 % Expected volatility 29.1 % 35.6 % Risk-free interest rate 1.4 % 2.0 % Expected term (in years) 6.5 7.5 Weighted-average grant-date fair value $ 10.16 $ 19.60
Unvested Restricted Stock Award and Restricted Share Unit Activity	The following table represents unvested restricted stock award and restricted share unit activity for the following periods: For the Nine Months Ended September 30 2016 2015 Balance at beginning of period 507,130 506,289 Granted 244,074 203,762 Forfeited (16,890 ) (23,471 ) Earned and issued (184,873 ) (170,513 ) Balance at end of period 549,441 516,067
Schedule of Share and Dividend Equivalent Share Award Activity	The following table represents phantom stock award and performance unit activity during the periods indicated: (Dollars in thousands) Number of share equivalents (1) Value of share equivalents (2) Balance, December 31, 2015 462,430 $ 25,466 Granted 200,761 13,475 Forfeited share equivalents (27,267 ) 1,830 Vested share equivalents (158,491 ) 8,161 Balance, September 30, 2016 477,433 $ 32,045 Balance, December 31, 2014 475,347 $ 30,826 Granted 162,740 9,473 Forfeited share equivalents (28,728 ) 1,672 Vested share equivalents (138,678 ) 8,832 Balance, September 30, 2015 470,681 $ 27,398 (1) Number of share equivalents includes all reinvested dividend equivalents for the periods indicated. (2) 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 $67.12 and $58.21 on September 30, 2016 , and 2015 , 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 following periods: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2016 2015 2016 2015 Compensation expense related to stock options $ 513 $ 455 $ 1,500 $ 1,400
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 periods indicated: For the Three Months Ended September 30 For the Nine Months Ended September 30 (Dollars in thousands) 2016 2015 2016 2015 Compensation expense related to restricted stock awards and restricted share units $ 3,014 $ 2,935 $ 9,729 $ 8,739
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) 2016 2015 2016 2015 Compensation expense related to phantom stock and performance units $ 3,127 $ 2,976 $ 8,325 $ 9,482

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
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. See Note 1, Summary of Significant Accounting Policies, in the 2015 Annual Report on Form 10-K for the year ended December 31, 2015, for a description of how fair value measurements are determined. September 30, 2016 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,885,413 $ — $ 2,885,413 Mortgage loans held for sale — 210,866 — 210,866 Derivative instruments — 55,804 — 55,804 Total $ — $ 3,152,083 $ — $ 3,152,083 Liabilities Derivative instruments $ — $ 58,939 $ — $ 58,939 Total $ — $ 58,939 $ — $ 58,939 December 31, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 2,800,286 $ — $ 2,800,286 Mortgage loans held for sale — 166,247 — 166,247 Derivative instruments — 30,486 — 30,486 Total $ — $ 2,997,019 $ — $ 2,997,019 Liabilities Derivative instruments $ — $ 24,939 $ — $ 24,939 Total $ — $ 24,939 $ — $ 24,939
Financial Asset and Liabilities Measured at Fair Value on Nonrecurring Basis	The Company has segregated all 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, 2016 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 85,463 $ 85,463 OREO, net — — 405 405 Total $ — $ — $ 85,868 $ 85,868 December 31, 2015 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 31,669 $ 31,669 OREO, net — — 1,662 1,662 Total $ — $ — $ 33,331 $ 33,331
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, 2016 December 31, 2015 (Dollars in thousands) Aggregate Aggregate Aggregate Aggregate Aggregate Aggregate Mortgage loans held for sale, at fair value $ 210,866 $ 203,293 $ 7,573 $ 166,247 $ 161,083 $ 5,164

Fair Value of Financial Instr38

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2016
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 included in the tables below. See Note 1, Summary of Significant Accounting Policies, in the 2015 Annual Report on Form 10-K for the year ended December 31, 2015, for a description of how fair value measurements are determined. September 30, 2016 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 1,101,253 $ 1,101,253 $ 1,101,253 $ — $ — Investment securities 2,976,066 2,978,823 — 2,978,823 — Loans and loans held for sale, net of unearned income and allowance for loan losses 14,987,172 15,032,960 — 210,866 14,822,094 FDIC loss share receivables 24,406 6,343 — — 6,343 Derivative instruments 55,804 55,804 — 55,804 — Financial Liabilities Deposits $ 16,522,517 $ 16,485,224 $ — $ — $ 16,485,224 Short-term borrowings 713,272 713,272 353,272 360,000 — Long-term debt 672,438 660,140 — — 660,140 Derivative instruments 58,939 58,939 — 58,939 — December 31, 2015 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 510,267 $ 510,267 $ 510,267 $ — $ — Investment securities 2,899,214 2,901,247 — 2,901,247 — Loans and loans held for sale, net of unearned income and allowance for loan losses 14,355,297 14,674,749 — 166,247 14,508,502 FDIC loss share receivables 39,878 9,163 — — 9,163 Derivative instruments 30,486 30,486 — 30,486 — Financial Liabilities Deposits $ 16,178,748 $ 15,696,245 $ — $ — $ 15,696,245 Short-term borrowings 326,617 326,617 216,617 110,000 — Long-term debt 340,447 309,847 — — 309,847 Derivative instruments 24,939 24,939 — 24,939 —

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	Three Months Ended September 30, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 178,521 $ 1,982 $ 1 $ 180,504 Interest expense 15,944 1,143 — 17,087 Net interest income 162,577 839 1 163,417 Provision for loan losses 12,443 41 — 12,484 Mortgage income 850 20,957 — 21,807 Service charges on deposit accounts 11,066 — — 11,066 Title revenue — — 6,001 6,001 Other non-interest income 20,946 1 — 20,947 Allocated expenses (3,914 ) 3,010 904 — Non-interest expense 127,690 5,891 4,558 138,139 Income before income tax expense 59,220 12,855 540 72,615 Income tax expense 19,282 5,048 217 24,547 Net income $ 39,938 $ 7,807 $ 323 $ 48,068 Total loans and loans held for sale, net of unearned income $ 14,957,337 $ 178,028 $ — $ 15,135,365 Total assets 20,537,304 226,906 24,356 20,788,566 Total deposits 16,513,867 8,650 — 16,522,517 Average assets 20,061,071 305,996 25,761 20,392,828 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 263 20,365 — 20,628 Service charges on deposit accounts 11,342 — — 11,342 Title revenue — — 6,627 6,627 Other non-interest income 18,880 1 — 18,881 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, net of unearned income $ 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 Nine Months Ended September 30, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 530,409 $ 5,723 $ 2 $ 536,134 Interest expense 45,380 3,181 — 48,561 Net interest income 485,029 2,542 2 487,573 Provision for loan losses 39,214 41 — 39,255 Mortgage income 856 66,882 — 67,738 Service charges on deposit accounts 32,957 — — 32,957 Title revenue — — 16,881 16,881 Other non-interest income 62,999 8 — 63,007 Allocated expenses (10,468 ) 8,007 2,461 — Non-interest expense 367,985 33,909 13,201 415,095 Income before income tax expense 185,110 27,475 1,221 213,806 Income tax expense 60,841 10,826 492 72,159 Net income $ 124,269 $ 16,649 $ 729 $ 141,647 Total loans and loans held for sale, net of unearned income $ 14,957,337 $ 178,028 $ — $ 15,135,365 Total assets 20,537,304 226,906 24,356 20,788,566 Total deposits 16,513,867 8,650 — 16,522,517 Average assets 19,705,052 289,037 26,626 20,020,715 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 830 63,067 — 63,897 Service charges on deposit accounts 30,766 — — 30,766 Title revenue — — 17,402 17,402 Other non-interest income 55,834 (2 ) (7 ) 55,825 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, net of unearned income $ 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

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Summary of Financial Instruments Outstanding	At September 30, 2016 and December 31, 2015, respectively, the Company had the following financial instruments outstanding and related reserves, whose contract amounts represent credit risk: (Dollars in thousands) September 30, 2016 December 31, 2015 Commitments to grant loans $ 398,754 $ 61,240 Unfunded commitments under lines of credit 4,876,141 4,617,802 Commercial and standby letters of credit 165,365 150,281 Reserve for unfunded lending commitments 11,990 14,145

Basis of Presentation (Detail)

Basis of Presentation (Detail) $ in Millions	Sep. 30, 2016USD ($)State	Dec. 31, 2015USD ($)
Schedule Of Significant Accounting Policies
Maximum loss exposure to non-consolidated VIEs | $	$ 130	$ 160
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) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Business Acquisition
Maximum period for subject to change estimated fair values after acquisition date	1 year
Florida Bank Group Inc. and Old Florida Bancshares Inc.
Business Acquisition
Increase in goodwill due to purchase price allocations	$ 2.3

Acquisition Activity - Schedule

Acquisition Activity - Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable (Detail) - USD ($) shares in Thousands, $ in Thousands	May 31, 2015	Mar. 31, 2015	Feb. 28, 2015	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Non-Equity consideration
Goodwill				$ 726,856	$ 724,603	$ 517,526
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			73,043
Goodwill			$ 17,442
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		152,375
Goodwill		$ 100,777
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	103,569
Goodwill	$ 86,695

Acquisition Activity - Schedu44

Acquisition Activity - Schedule of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	May 31, 2015	Mar. 31, 2015	Feb. 28, 2015
Florida Bank Group, Inc.
Assets
Cash and cash equivalents		$ 72,982			$ 72,982
Investment securities		107,372			107,236
Loans		307,531			312,902
Other real estate owned		423			498
Core deposit intangible		4,489			0
Deferred tax asset, net		26,720			18,151
Other assets		20,868			29,817
Total Assets		540,385			541,586
Liabilities
Interest-bearing deposits		282,680			282,417
Non-interest-bearing deposits		109,548			109,548
Borrowings		68,598			60,000
Other liabilities		6,516			1,898
Total Liabilities		467,342			$ 453,863
Florida Bank Group, Inc. | Preliminary Fair Value Adjustments
Assets
Cash and cash equivalents		0
Investment securities		136
Loans		(5,371)
Other real estate owned		(75)
Core deposit intangible		4,489
Deferred tax asset, net		8,569
Other assets		(8,949)
Total Assets		(1,201)
Liabilities
Interest-bearing deposits		263
Non-interest-bearing deposits		0
Borrowings		8,598
Other liabilities		4,618
Total Liabilities		13,479
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		1,062,951		1,073,773
Other real estate owned		5,964		4,515
Core deposit intangible		6,821		0
Deferred tax asset, net		13,878		9,490
Other assets		23,311		30,549
Total Assets		1,546,774		1,552,176
Liabilities
Interest-bearing deposits		1,048,888		1,048,765
Non-interest-bearing deposits		340,869		340,869
Borrowings		1,528		1,528
Other liabilities		3,114		3,038
Total Liabilities		1,394,399		$ 1,394,200
Old Florida Bancshares, Inc. | Preliminary Fair Value Adjustments
Assets
Cash and cash equivalents		0
Investment securities		0
Loans held for sale		0
Loans		(10,822)
Other real estate owned		1,449
Core deposit intangible		6,821
Deferred tax asset, net		4,388
Other assets		(7,238)
Total Assets		(5,402)
Liabilities
Interest-bearing deposits		123
Non-interest-bearing deposits		0
Borrowings		0
Other liabilities		76
Total Liabilities		$ 199
Georgia Commerce Bancshares, Inc.
Assets
Cash and cash equivalents	$ 51,059		$ 51,059
Investment securities	134,903		135,710
Loans held for sale	1,249		1,249
Loans	792,119		807,726
Other real estate owned	5,588		9,795
Core deposit intangible	6,720		0
Deferred tax asset, net	9,055		3,603
Other assets	28,299		28,956
Total Assets	1,028,992		1,038,098
Liabilities
Interest-bearing deposits	658,309		658,133
Non-interest-bearing deposits	249,739		249,739
Borrowings	13,204		13,204
Other liabilities	4,171		4,171
Total Liabilities	925,423		$ 925,247
Georgia Commerce Bancshares, Inc. | Preliminary Fair Value Adjustments
Assets
Cash and cash equivalents	0
Investment securities	(807)
Loans held for sale	0
Loans	(15,607)
Other real estate owned	(4,207)
Core deposit intangible	6,720
Deferred tax asset, net	5,452
Other assets	(657)
Total Assets	(9,106)
Liabilities
Interest-bearing deposits	176
Non-interest-bearing deposits	0
Borrowings	0
Other liabilities	0
Total Liabilities	$ 176

Investment Securities (Detail)

Investment Securities (Detail) $ in Billions	Sep. 30, 2016USD ($)Security	Dec. 31, 2015USD ($)Security
Investments, Debt and Equity Securities [Abstract]
Carrying value of pledged securities | $	$ 1.3	$ 1.4
Number of debt securities held | Security	73	252
Unrealized losses on debt securities (percent of amortized cost)	0.55%	1.10%

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, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities
Amortized cost	$ 90,653	$ 98,928
Gross unrealized gains	2,932	2,910
Gross unrealized losses	(175)	(877)
Estimated fair value	93,410	100,961
Schedule of Available-for-sale Securities
Amortized cost	2,845,969	2,803,430
Gross Unrealized Gains	41,364	15,477
Gross Unrealized Losses	(1,920)	(18,621)
Securities available for sale	2,885,413	2,800,286
U.S. Government-Sponsored Enterprise Obligations
Schedule of Available-for-sale Securities
Amortized cost	217,859	252,514
Gross Unrealized Gains	2,613	1,161
Gross Unrealized Losses	0	(1,592)
Securities available for sale	220,472	252,083
Obligations of States and Political Subdivisions
Schedule of Available-for-sale Securities
Amortized cost	245,086	182,541
Gross Unrealized Gains	7,946	5,429
Gross Unrealized Losses	(127)	(9)
Securities available for sale	252,905	187,961
Mortgage-Backed Securities
Schedule of Available-for-sale Securities
Amortized cost	2,283,336	2,272,879
Gross Unrealized Gains	29,475	8,457
Gross Unrealized Losses	(1,743)	(16,523)
Securities available for sale	2,311,068	2,264,813
Other Securities
Schedule of Available-for-sale Securities
Amortized cost	99,688	95,496
Gross Unrealized Gains	1,330	430
Gross Unrealized Losses	(50)	(497)
Securities available for sale	100,968	95,429
Obligations of States and Political Subdivisions
Schedule of Held-to-maturity Securities
Amortized cost	64,898	69,979
Gross unrealized gains	2,727	2,803
Gross unrealized losses	0	(101)
Estimated fair value	67,625	72,681
Mortgage-Backed Securities
Schedule of Held-to-maturity Securities
Amortized cost	25,755	28,949
Gross unrealized gains	205	107
Gross unrealized losses	(175)	(776)
Estimated fair value	$ 25,785	$ 28,280

Investment Securities - Sched47

Investment Securities - Schedule of Securities with Gross Unrealized Losses Aggregated by Investment Category (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Gross Unrealized Losses
Less than twelve months	$ 0	$ (54)
Over twelve months	(175)	(823)
Total	(175)	(877)
Fair Value
Less than twelve months	2,212	5,529
Over twelve months	11,698	21,735
Total	13,910	27,264
Gross Unrealized Losses
Less than twelve months	(1,021)	(13,448)
Over twelve months	(899)	(5,173)
Total	(1,920)	(18,621)
Fair Value
Less than twelve months	267,529	1,515,493
Over twelve months	98,175	213,830
Total	365,704	1,729,323
U.S. Government-Sponsored Enterprise Obligations
Gross Unrealized Losses
Less than twelve months		(1,214)
Over twelve months		(378)
Total		(1,592)
Fair Value
Less than twelve months		177,839
Over twelve months		28,116
Total		205,955
Obligations of States and Political Subdivisions
Gross Unrealized Losses
Less than twelve months	(127)	(9)
Over twelve months	0	0
Total	(127)	(9)
Fair Value
Less than twelve months	30,222	5,765
Over twelve months	0	0
Total	30,222	5,765
Mortgage-Backed Securities
Gross Unrealized Losses
Less than twelve months	(893)	(11,737)
Over twelve months	(850)	(4,786)
Total	(1,743)	(16,523)
Fair Value
Less than twelve months	236,800	1,279,914
Over twelve months	94,259	185,215
Total	331,059	1,465,129
Other Securities
Gross Unrealized Losses
Less than twelve months	(1)	(488)
Over twelve months	(49)	(9)
Total	(50)	(497)
Fair Value
Less than twelve months	507	51,975
Over twelve months	3,916	499
Total	4,423	52,474
Obligations of States and Political Subdivisions
Gross Unrealized Losses
Less than twelve months	0	(9)
Over twelve months	0	(92)
Total	0	(101)
Fair Value
Less than twelve months	2,212	1,999
Over twelve months	0	4,162
Total	2,212	6,161
Mortgage-Backed Securities
Gross Unrealized Losses
Less than twelve months	0	(45)
Over twelve months	(175)	(731)
Total	(175)	(776)
Fair Value
Less than twelve months	0	3,530
Over twelve months	11,698	17,573
Total	$ 11,698	$ 21,103

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, 2016USD ($)Security	Dec. 31, 2015USD ($)Security
Schedule of Available-for-sale Securities
Number of securities | Security	30	43
Amortized cost basis	$ 110,947	$ 241,561
Unrealized loss	$ 1,074	$ 5,996
Issued by Fannie Mae, Freddie Mac, or Ginnie Mae
Schedule of Available-for-sale Securities
Number of securities | Security	27	40
Amortized cost basis	$ 106,982	$ 236,800
Unrealized loss	$ 1,025	$ 5,895
Issued by Political Subdivisions
Schedule of Available-for-sale Securities
Number of securities | Security	0	2
Amortized cost basis	$ 0	$ 4,253
Unrealized loss	$ 0	$ 92
Others
Schedule of Available-for-sale Securities
Number of securities | Security	3	1
Amortized cost basis	$ 3,965	$ 508
Unrealized loss	$ 49	$ 9

Investment Securities - Sched49

Investment Securities - Schedule of Amortized Cost and Estimated Fair Value of Investment Securities by Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Weighted Average Yield
Within one year or less	2.36%
One through five years	1.64%
After five through ten years	2.29%
Over ten years	1.97%
Weighted average yield	2.01%
Amortized Cost
Within one year or less	$ 19,560
One through five years	275,596
After five through ten years	585,382
Over ten years	1,965,431
Amortized Cost	2,845,969
Estimated Fair Value
Within one year or less	19,658
One through five years	279,271
After five through ten years	602,194
Over ten years	1,984,290
Estimated fair value	$ 2,885,413	$ 2,800,286
Weighted Average Yield
Within one year or less	2.42%
One through five years	2.97%
After five through ten years	3.07%
Over ten years	2.74%
Weighted average yield	2.82%
Amortized Cost
Within one year or less	$ 2,059
One through five years	10,295
After five through ten years	18,357
Over ten years	59,942
Amortized cost	90,653	98,928
Estimated Fair Value
Within one year or less	2,076
One through five years	10,583
After five through ten years	19,214
Over ten years	61,537
Estimated fair value	$ 93,410	$ 100,961

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Realized gains	$ 12	$ 425	$ 2,947	$ 1,786
Realized losses	0	(145)	(950)	(217)
Net realized gains (losses)	$ 12	$ 280	$ 1,997	$ 1,569

Investment Securities - Sched51

Investment Securities - Schedule of Securities in Other Assets on Company's Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Federal Home Loan Bank (FHLB) stock	$ 47,589	$ 16,265
Federal Reserve Bank (FRB) stock	48,584	48,584
Other investments	1,159	1,159
Total	$ 97,332	$ 66,008

Loans (Detail)

Loans (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)bank	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Accounts, Notes, Loans and Financing Receivable
Failed banks acquired since 2009 | bank	6
Covered loans receivable	$ 202,211		$ 229,217
Deferred loan origination fees	20,900		18,700
Deposit liabilities reclassified as loans receivable	3,800		5,100
Loans with carrying value pledged to secure public deposits and other borrowings	$ 4,300,000		3,900,000
Carrying amounts of loans acquired			2,200,000
Threshold period for loans in default	30 days
Troubled Debt Restructurings
Accounts, Notes, Loans and Financing Receivable
Total TDRs	$ 218,600	$ 48,600
Accrual status TDR	94,300	21,800
Non-accrual status TDR	124,300	$ 26,800
Florida Bank Group, Inc.
Accounts, Notes, Loans and Financing Receivable
Acquired loans			300,000
Old Florida Bancshares, Inc.
Accounts, Notes, Loans and Financing Receivable
Acquired loans			1,100,000
Georgia Commerce
Accounts, Notes, Loans and Financing Receivable
Acquired loans			800,000
Loans Acquired Without Deteriorated Credit Quality
Accounts, Notes, Loans and Financing Receivable
Carrying amounts of loans acquired			2,100,000
Loans Acquired With Deteriorated Credit Quality
Accounts, Notes, Loans and Financing Receivable
Carrying amounts of loans acquired			57,800
Acquired Covered Loan
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	202,200		229,200
Acquired Covered Loan | Residential Mortgage and Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable
Covered loans receivable	$ 169,000		$ 191,700

Loans - Schedule of Non-Covered

Loans - Schedule of Non-Covered and Covered Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	$ 14,924,499	$ 14,327,428
Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	10,743,853	10,198,855
Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	6,681,215	6,073,511
Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	3,462,997	3,444,578
Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	599,641	680,766
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	1,270,530	1,195,319
Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	2,910,116	2,933,254
Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	2,151,130	2,066,167
Consumer and Other Loans | Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	153,913	246,298
Consumer and Other Loans | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	605,073	620,789
Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	12,413,370	11,190,520
Legacy Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	9,119,234	8,133,341
Legacy Loans | Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	5,419,483	4,504,062
Legacy Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	3,101,472	2,952,102
Legacy Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	598,279	677,177
Legacy Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	840,082	694,023
Legacy Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	2,454,054	2,363,156
Legacy Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	1,755,295	1,575,643
Legacy Loans | Consumer and Other Loans | Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	153,904	246,214
Legacy Loans | Consumer and Other Loans | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	544,855	541,299
Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	2,511,129	3,136,908
Acquired Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	1,624,619	2,065,514
Acquired Loans | Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	1,261,732	1,569,449
Acquired Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	361,525	492,476
Acquired Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	1,362	3,589
Acquired Loans | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	430,448	501,296
Acquired Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	456,062	570,098
Acquired Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	395,835	490,524
Acquired Loans | Consumer and Other Loans | Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	9	84
Acquired Loans | Consumer and Other Loans | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Non-covered loans, net of unearned income	$ 60,218	$ 79,490

Loans - Schedule of Aging of No

Loans - Schedule of Aging of Non-Covered Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	$ 356,021	$ 102,733
Total Loans	14,722,288	14,098,211
Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	315,357	73,846
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	18,205	14,806
Consumer
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	22,459	14,081
Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	46,093	20,733
Non-accrual Loans	227,122	50,928
Total Loans	12,413,370	11,190,520
Legacy Loans | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	12,140,155	11,118,859
Legacy Loans | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	28,437	13,839
Legacy Loans | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	12,720	6,270
Legacy Loans | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	4,936	624
Legacy Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total Loans	9,119,234	8,133,341
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction
Accounts, Notes, Loans and Financing Receivable
Accruing	1,234	801
Non-accrual Loans	25	120
Total Loans	696,127	636,481
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	694,868	635,560
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	801
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	1,234	0
Legacy Loans | Commercial Loans | Commercial Real Estate - Other
Accounts, Notes, Loans and Financing Receivable
Accruing	4,348	3,575
Non-accrual Loans	14,920	15,422
Total Loans	4,723,356	3,867,581
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	4,704,088	3,848,584
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	1,514	2,687
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	445	793
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	2,389	95
Legacy Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	16,265	2,034
Non-accrual Loans	34,966	6,659
Total Loans	3,101,472	2,952,102
Legacy Loans | Commercial Loans | Commercial and Industrial | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	3,050,241	2,943,409
Legacy Loans | Commercial Loans | Commercial and Industrial | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	14,713	1,208
Legacy Loans | Commercial Loans | Commercial and Industrial | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	1,404	739
Legacy Loans | Commercial Loans | Commercial and Industrial | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	148	87
Legacy Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Accruing	0	15
Non-accrual Loans	153,620	7,081
Total Loans	598,279	677,177
Legacy Loans | Commercial Loans | Energy-Related | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	444,659	670,081
Legacy Loans | Commercial Loans | Energy-Related | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	15
Legacy Loans | Commercial Loans | Energy-Related | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Legacy Loans | Commercial Loans | Energy-Related | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Legacy Loans | Residential Mortgage Loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	9,112	4,002
Non-accrual Loans	13,816	13,674
Total Loans	840,082	694,023
Legacy Loans | Residential Mortgage Loans | Residential Mortgage | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	817,154	676,347
Legacy Loans | Residential Mortgage Loans | Residential Mortgage | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	1,396	1,075
Legacy Loans | Residential Mortgage Loans | Residential Mortgage | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	7,389	2,485
Legacy Loans | Residential Mortgage Loans | Residential Mortgage | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	327	442
Legacy Loans | Consumer | Consumer - Home Equity
Accounts, Notes, Loans and Financing Receivable
Accruing	8,276	4,419
Non-accrual Loans	7,018	5,628
Total Loans	1,755,295	1,575,643
Legacy Loans | Consumer | Consumer - Home Equity | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	1,740,001	1,565,596
Legacy Loans | Consumer | Consumer - Home Equity | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	6,207	3,549
Legacy Loans | Consumer | Consumer - Home Equity | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	1,968	870
Legacy Loans | Consumer | Consumer - Home Equity | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	101	0
Legacy Loans | Consumer | Consumer - Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	2,556	2,705
Non-accrual Loans	1,340	1,181
Total Loans	153,904	246,214
Legacy Loans | Consumer | Consumer - Indirect Automobile | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	150,008	242,328
Legacy Loans | Consumer | Consumer - Indirect Automobile | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	2,151	2,187
Legacy Loans | Consumer | Consumer - Indirect Automobile | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	405	518
Legacy Loans | Consumer | Consumer - Indirect Automobile | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Legacy Loans | Consumer | Consumer - Credit Card
Accounts, Notes, Loans and Financing Receivable
Accruing	426	507
Non-accrual Loans	438	394
Total Loans	80,452	77,261
Legacy Loans | Consumer | Consumer - Credit Card | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	79,588	76,360
Legacy Loans | Consumer | Consumer - Credit Card | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	311	394
Legacy Loans | Consumer | Consumer - Credit Card | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	115	113
Legacy Loans | Consumer | Consumer - Credit Card | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Legacy Loans | Consumer | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Accruing	3,876	2,675
Non-accrual Loans	979	769
Total Loans	464,403	464,038
Legacy Loans | Consumer | Consumer - Other | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	459,548	460,594
Legacy Loans | Consumer | Consumer - Other | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	2,145	1,923
Legacy Loans | Consumer | Consumer - Other | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	994	752
Legacy Loans | Consumer | Consumer - Other | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	737	0
Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	4,265	5,357
Non-accrual Loans	8,399	5,421
Discount/Premium	(18,363)	(23,856)
Acquired Impaired Loans	569,047	724,719
Total Loans	2,511,129	3,136,908
Acquired Loans | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	1,947,781	2,425,267
Acquired Loans | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	1,501	2,761
Acquired Loans | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	2,467	2,305
Acquired Loans | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	297	291
Acquired Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total Loans	1,624,619	2,065,514
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction
Accounts, Notes, Loans and Financing Receivable
Accruing	0	297
Non-accrual Loans	1,946	0
Discount/Premium	(285)	(358)
Acquired Impaired Loans	37,516	56,320
Total Loans	80,795	125,426
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	41,618	69,167
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	180
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	117
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Commercial Loans | Commercial Real Estate - Other
Accounts, Notes, Loans and Financing Receivable
Accruing	387	1,566
Non-accrual Loans	1,976	1,491
Discount/Premium	(4,991)	(4,479)
Acquired Impaired Loans	270,046	354,757
Total Loans	1,180,937	1,444,023
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	913,519	1,090,688
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	861
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	387	705
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	810	623
Non-accrual Loans	1,770	1,154
Discount/Premium	(705)	(2,517)
Acquired Impaired Loans	35,154	50,762
Total Loans	361,525	492,476
Acquired Loans | Commercial Loans | Commercial and Industrial | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	324,496	442,454
Acquired Loans | Commercial Loans | Commercial and Industrial | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	561	623
Acquired Loans | Commercial Loans | Commercial and Industrial | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	249	0
Acquired Loans | Commercial Loans | Commercial and Industrial | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Non-accrual Loans	0	170
Discount/Premium	(7)	2
Acquired Impaired Loans	0	1,231
Total Loans	1,362	3,589
Acquired Loans | Commercial Loans | Energy-Related | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	1,369	2,186
Acquired Loans | Commercial Loans | Energy-Related | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Commercial Loans | Energy-Related | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Commercial Loans | Energy-Related | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Residential Mortgage Loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	1,619	947
Non-accrual Loans	1,258	1,109
Discount/Premium	(5,855)	(6,601)
Acquired Impaired Loans	125,749	140,580
Total Loans	430,448	501,296
Acquired Loans | Residential Mortgage Loans | Residential Mortgage | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	307,677	365,261
Acquired Loans | Residential Mortgage Loans | Residential Mortgage | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	7
Acquired Loans | Residential Mortgage Loans | Residential Mortgage | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	1,339	940
Acquired Loans | Residential Mortgage Loans | Residential Mortgage | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	280	0
Acquired Loans | Consumer | Consumer - Home Equity
Accounts, Notes, Loans and Financing Receivable
Accruing	725	1,329
Non-accrual Loans	1,206	1,291
Discount/Premium	(1,762)	(7,333)
Acquired Impaired Loans	94,502	114,130
Total Loans	395,835	490,524
Acquired Loans | Consumer | Consumer - Home Equity | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	301,164	381,107
Acquired Loans | Consumer | Consumer - Home Equity | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	419	622
Acquired Loans | Consumer | Consumer - Home Equity | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	289	416
Acquired Loans | Consumer | Consumer - Home Equity | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	17	291
Acquired Loans | Consumer | Consumer - Indirect Automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Non-accrual Loans	0	0
Discount/Premium	0	0
Acquired Impaired Loans	0	65
Total Loans	9	84
Acquired Loans | Consumer | Consumer - Indirect Automobile | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	9	19
Acquired Loans | Consumer | Consumer - Indirect Automobile | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Consumer | Consumer - Indirect Automobile | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Consumer | Consumer - Indirect Automobile | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Consumer | Consumer - Credit Card
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Non-accrual Loans	0	0
Discount/Premium	0	0
Acquired Impaired Loans	507	582
Total Loans	507	582
Acquired Loans | Consumer | Consumer - Credit Card | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Consumer | Consumer - Credit Card | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Consumer | Consumer - Credit Card | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Consumer | Consumer - Credit Card | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Acquired Loans | Consumer | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Accruing	724	595
Non-accrual Loans	243	206
Discount/Premium	(4,758)	(2,570)
Acquired Impaired Loans	5,573	6,292
Total Loans	59,711	78,908
Acquired Loans | Consumer | Consumer - Other | Current or Less Than 30 days past due
Accounts, Notes, Loans and Financing Receivable
Accruing	57,929	74,385
Acquired Loans | Consumer | Consumer - Other | 30-59 days
Accounts, Notes, Loans and Financing Receivable
Accruing	521	468
Acquired Loans | Consumer | Consumer - Other | 60-89 days
Accounts, Notes, Loans and Financing Receivable
Accruing	203	127
Acquired Loans | Consumer | Consumer - Other | 90 days
Accounts, Notes, Loans and Financing Receivable
Accruing	$ 0	$ 0

Loans - Schedule of Carrying Am

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, 2016USD ($)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period
Contractually required principal and interest at acquisition	$ 2,384,114
Expected losses and foregone interest	(15,539)
Cash flows expected to be collected at acquisition	2,368,575
Fair value of acquired loans at acquisition	$ 2,105,466

Loans - Schedule of Carrying 56

Loans - Schedule of Carrying Amount of Loans Acquired (Detail) - Florida Bank Group, Inc., Old Florida Bancshares, Inc., Georgia Commerce Bancshares, Inc. - Acquired Impaired Loans - Receivables Acquired With Deteriorated Credit Quality $ in Thousands	Sep. 30, 2016USD ($)
Accounts, Notes, Loans and Financing Receivable
Contractually required principal and interest at acquisition	$ 76,445
Non-accretable difference (expected losses and foregone interest)	(11,867)
Cash flows expected to be collected at acquisition	64,578
Accretable yield	(6,823)
Basis in acquired loans at acquisition	$ 57,755

Loans - Summary of Changes in A

Loans - Summary of Changes in Accretable Yields of Acquired Loans (Detail) - Acquired Impaired Loans - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 227,502	$ 287,651
Acquisition	0	4,592
Transfers from non-accretable difference to accretable yield	5,491	7,199
Accretion	(52,603)	(60,305)
Changes in expected cash flows not affecting nonaccretable differences	12,743	(1,511)
Balance at end of period	$ 193,133	$ 237,626

Loans - Schedule of Modified TD

Loans - Schedule of Modified TDRs (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Receivables [Abstract]
Extended maturities	$ 76,059	$ 15,932
Maturity and interest rate adjustment	26,372	23,552
Forbearance	75,953	1,228
Movement to or extension of interest-rate only payments	1,689	0
Interest rate adjustment	133	0
Other concession(s)	38,390	7,887
Total	$ 218,596	$ 48,599

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, 2016USD ($)SecurityLoan	Sep. 30, 2015USD ($)SecurityLoan
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	377	27
Pre-modification outstanding recorded investment	$ 224,148	$ 49,640
Post-modification outstanding recorded investment	$ 218,596	$ 48,599
Number of loans | SecurityLoan	61	20
Recorded investment	$ 11,217	$ 29,468
Commercial Loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	23	8
Pre-modification outstanding recorded investment	$ 22,765	$ 26,408
Post-modification outstanding recorded investment	$ 16,441	$ 25,572
Number of loans | SecurityLoan	5	4
Recorded investment	$ 668	$ 12,939
Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	49	18
Pre-modification outstanding recorded investment	$ 44,144	$ 19,798
Post-modification outstanding recorded investment	$ 43,083	$ 19,643
Number of loans | SecurityLoan	21	15
Recorded investment	$ 7,476	$ 13,145
Commercial Loans | Energy-Related
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	28	1
Pre-modification outstanding recorded investment	$ 143,012	$ 3,434
Post-modification outstanding recorded investment	$ 145,298	$ 3,384
Number of loans | SecurityLoan	1	1
Recorded investment	$ 1,394	$ 3,384
Residential Mortgage | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	31	0
Pre-modification outstanding recorded investment	$ 4,784	$ 0
Post-modification outstanding recorded investment	$ 4,659	$ 0
Number of loans | SecurityLoan	5	0
Recorded investment	$ 364	$ 0
Consumer and Other Loans | Consumer - Home Equity
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	104	0
Pre-modification outstanding recorded investment	$ 7,071	$ 0
Post-modification outstanding recorded investment	$ 6,805	$ 0
Number of loans | SecurityLoan	16	0
Recorded investment	$ 1,037	$ 0
Consumer and Other Loans | Consumer - Other
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	142	0
Pre-modification outstanding recorded investment	$ 2,372	$ 0
Post-modification outstanding recorded investment	$ 2,310	$ 0
Number of loans | SecurityLoan	13	0
Recorded investment	$ 278	$ 0

Allowance for Credit Losses a60

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period			$ 138,378	$ 130,131
Provision for (Reversal of) loan losses before benefit attributable to FDIC loss share agreements			38,015	17,855
Adjustment attributable to FDIC loss share arrangements			1,240	1,342
Net provision for loan losses	$ 12,484	$ 5,062	39,255	19,197
Adjustment attributable to FDIC loss share arrangements			(1,240)	(1,342)
Transfer of balance to OREO and other			2,045	9,768
Loans charged-off			(30,054)	(13,025)
Recoveries			3,899	5,061
Allowance for loan losses at end of period	148,193	130,254	148,193	130,254
Financing Receivable, Allowance For Credit Losses, Unfunded Commitments [Roll Forward]
Reserve for unfunded commitments at beginning of period			14,145	11,801
Provision for (Reversal of) unfunded lending commitments			(2,155)	2,724
Reserve for unfunded commitments at end of period	11,990	14,525	11,990	14,525
Allowance for credit losses at end of period	160,183	144,779	160,183	144,779
Legacy Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period			93,808	76,174
Provision for (Reversal of) loan losses before benefit attributable to FDIC loss share agreements			40,516	17,743
Adjustment attributable to FDIC loss share arrangements			0	0
Net provision for loan losses			40,516	17,743
Adjustment attributable to FDIC loss share arrangements			0	0
Transfer of balance to OREO and other			0	0
Loans charged-off			(28,559)	(12,073)
Recoveries			3,124	4,556
Allowance for loan losses at end of period	108,889	86,400	108,889	86,400
Financing Receivable, Allowance For Credit Losses, Unfunded Commitments [Roll Forward]
Reserve for unfunded commitments at beginning of period			14,145	11,801
Provision for (Reversal of) unfunded lending commitments			(2,155)	2,724
Reserve for unfunded commitments at end of period	11,990	14,525	11,990	14,525
Allowance for credit losses at end of period	120,879	100,925	120,879	100,925
Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period			44,570	53,957
Provision for (Reversal of) loan losses before benefit attributable to FDIC loss share agreements			(2,501)	112
Adjustment attributable to FDIC loss share arrangements			1,240	1,342
Net provision for loan losses			(1,261)	1,454
Adjustment attributable to FDIC loss share arrangements			(1,240)	(1,342)
Transfer of balance to OREO and other			2,045	9,768
Loans charged-off			(1,495)	(952)
Recoveries			775	505
Allowance for loan losses at end of period	39,304	43,854	39,304	43,854
Financing Receivable, Allowance For Credit Losses, Unfunded Commitments [Roll Forward]
Reserve for unfunded commitments at beginning of period			0	0
Provision for (Reversal of) 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	$ 39,304	$ 43,854	$ 39,304	$ 43,854

Allowance for Credit Losses a61

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, 2016	Sep. 30, 2015	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	$ 138,378	$ 130,131
Transfer of balance to OREO and other	2,045	9,768
Loans charged off	(30,054)	(13,025)
Recoveries	3,899	5,061
Allowance for loan losses at end of period	148,193	130,254
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	14,145	11,801
Reserve for unfunded commitments at end of period	11,990	14,525
Loans, net of unearned income:
Loans, net of unearned income	202,211		$ 229,217
Non-Covered Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	93,808	76,174
Provision for (Reversal of) loan losses	40,516	17,743
Loans charged off	(28,559)	(12,073)
Recoveries	3,124	4,556
Allowance for loan losses at end of period	108,889	86,400
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	14,145	11,801
Provision for (Reversal of) unfunded commitments	(2,155)	2,724
Reserve for unfunded commitments at end of period	11,990	14,525
Allowance on loans individually evaluated for impairment	25,210	1,700
Allowance on loans collectively evaluated for impairment	83,679	84,700
Loans, net of unearned income:
Loans, net of unearned income	12,413,370	10,779,258
Balance at end of period individually evaluated for impairment	318,466	52,146
Balance at end of period collectively evaluated for impairment	12,094,904	10,727,112
Non-Covered Loans | Commercial Loans | Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	24,658	26,752
Provision for (Reversal of) loan losses	(651)	(947)
Loans charged off	(1,598)	(2,009)
Recoveries	766	1,535
Allowance for loan losses at end of period	23,175	25,331
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	4,160	3,370
Provision for (Reversal of) unfunded commitments	(427)	218
Reserve for unfunded commitments at end of period	3,733	3,588
Allowance on loans individually evaluated for impairment	655	883
Allowance on loans collectively evaluated for impairment	22,520	24,448
Loans, net of unearned income:
Loans, net of unearned income	5,419,483	4,321,723
Balance at end of period individually evaluated for impairment	31,405	26,463
Balance at end of period collectively evaluated for impairment	5,388,078	4,295,260
Non-Covered Loans | Commercial Loans | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	23,283	24,455
Provision for (Reversal of) loan losses	13,201	1,308
Loans charged off	(2,418)	(1,048)
Recoveries	251	49
Allowance for loan losses at end of period	34,317	24,764
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	3,448	3,733
Provision for (Reversal of) unfunded commitments	(46)	(149)
Reserve for unfunded commitments at end of period	3,402	3,584
Allowance on loans individually evaluated for impairment	8,996	817
Allowance on loans collectively evaluated for impairment	25,321	23,947
Loans, net of unearned income:
Loans, net of unearned income	3,101,472	2,779,503
Balance at end of period individually evaluated for impairment	58,464	22,076
Balance at end of period collectively evaluated for impairment	3,043,008	2,757,427
Non-Covered Loans | Commercial Loans | Energy-Related
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	23,863	5,949
Provision for (Reversal of) loan losses	18,998	9,269
Loans charged off	(14,672)	0
Recoveries	0	0
Allowance for loan losses at end of period	28,189	15,218
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	2,665	1,596
Provision for (Reversal of) unfunded commitments	(1,712)	2,037
Reserve for unfunded commitments at end of period	953	3,633
Allowance on loans individually evaluated for impairment	14,396	0
Allowance on loans collectively evaluated for impairment	13,793	15,218
Loans, net of unearned income:
Loans, net of unearned income	598,279	713,935
Balance at end of period individually evaluated for impairment	212,512	3,409
Balance at end of period collectively evaluated for impairment	385,767	710,526
Non-Covered Loans | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	3,947	2,678
Provision for (Reversal of) loan losses	248	1,474
Loans charged off	(240)	(224)
Recoveries	142	44
Allowance for loan losses at end of period	4,097	3,972
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	830	168
Provision for (Reversal of) unfunded commitments	(148)	650
Reserve for unfunded commitments at end of period	682	818
Allowance on loans individually evaluated for impairment	110	0
Allowance on loans collectively evaluated for impairment	3,987	3,972
Loans, net of unearned income:
Loans, net of unearned income	840,082	660,543
Balance at end of period individually evaluated for impairment	4,539	0
Balance at end of period collectively evaluated for impairment	835,543	660,543
Non-Covered Loans | Consumer and Other Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	18,057	16,340
Provision for (Reversal of) loan losses	8,720	6,639
Loans charged off	(9,631)	(8,792)
Recoveries	1,965	2,928
Allowance for loan losses at end of period	19,111	17,115
Reserve for unfunded commitments
Reserve for unfunded commitments at beginning of period	3,042	2,934
Provision for (Reversal of) unfunded commitments	178	(32)
Reserve for unfunded commitments at end of period	3,220	2,902
Allowance on loans individually evaluated for impairment	1,053	0
Allowance on loans collectively evaluated for impairment	18,058	17,115
Loans, net of unearned income:
Loans, net of unearned income	2,454,054	2,303,554
Balance at end of period individually evaluated for impairment	11,546	198
Balance at end of period collectively evaluated for impairment	2,442,508	2,303,356
Covered Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	44,570	53,957
Provision for (Reversal of) loan losses	(1,261)	1,454
Decrease in FDIC loss share receivable	(1,240)	(1,342)
Transfer of balance to OREO and other	(2,045)	(9,768)
Loans charged off	(1,495)	(952)
Recoveries	775	505
Allowance for loan losses at end of period	39,304	43,854
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	254	16
Allowance on loans collectively evaluated for impairment	39,050	43,838
Loans, net of unearned income:
Loans, net of unearned income	2,511,129	3,337,761
Balance at end of period individually evaluated for impairment	8,252	598
Balance at end of period collectively evaluated for impairment	1,933,830	2,555,360
Covered Loans | Receivables Acquired With Deteriorated Credit Quality
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	569,047	781,803
Covered Loans | Commercial Loans | Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	25,979	29,949
Provision for (Reversal of) loan losses	(1,952)	809
Decrease in FDIC loss share receivable	(34)	748
Transfer of balance to OREO and other	(380)	(6,096)
Loans charged off	(789)	0
Recoveries	102	8
Allowance for loan losses at end of period	22,926	25,418
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	177	0
Allowance on loans collectively evaluated for impairment	22,749	25,418
Loans, net of unearned income:
Loans, net of unearned income	1,261,732	1,658,028
Balance at end of period individually evaluated for impairment	5,647	0
Balance at end of period collectively evaluated for impairment	948,523	1,205,439
Covered Loans | Commercial Loans | Real Estate | Receivables Acquired With Deteriorated Credit Quality
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	307,562	452,589
Covered Loans | Commercial Loans | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	2,819	3,265
Provision for (Reversal of) loan losses	216	174
Decrease in FDIC loss share receivable	(50)	59
Transfer of balance to OREO and other	(467)	(282)
Loans charged off	0	(8)
Recoveries	217	116
Allowance for loan losses at end of period	2,735	3,324
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	77	0
Allowance on loans collectively evaluated for impairment	2,658	3,324
Loans, net of unearned income:
Loans, net of unearned income	361,525	523,468
Balance at end of period individually evaluated for impairment	1,926	142
Balance at end of period collectively evaluated for impairment	324,445	465,514
Covered Loans | Commercial Loans | Commercial and Industrial | Receivables Acquired With Deteriorated Credit Quality
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	35,154	57,812
Covered Loans | Commercial Loans | Energy-Related
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	125	51
Provision for (Reversal of) loan losses	(99)	67
Decrease in FDIC loss share receivable	0	0
Transfer of balance to OREO and other	0	0
Loans charged off	0	0
Recoveries	0	0
Allowance for loan losses at end of period	26	118
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	26	118
Loans, net of unearned income:
Loans, net of unearned income	1,362	5,521
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	1,362	5,521
Covered Loans | Commercial Loans | Energy-Related | Receivables Acquired With Deteriorated Credit Quality
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	0	0
Covered Loans | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	7,841	6,484
Provision for (Reversal of) loan losses	1,017	1,263
Decrease in FDIC loss share receivable	(833)	(277)
Transfer of balance to OREO and other	28	(472)
Loans charged off	0	(59)
Recoveries	33	4
Allowance for loan losses at end of period	8,086	6,943
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	8,086	6,943
Loans, net of unearned income:
Loans, net of unearned income	430,448	529,398
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	304,699	385,854
Covered Loans | Residential Mortgage | Receivables Acquired With Deteriorated Credit Quality
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	125,749	143,544
Covered Loans | Consumer and Other Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	7,806	14,208
Provision for (Reversal of) loan losses	(443)	(859)
Decrease in FDIC loss share receivable	(323)	(1,872)
Transfer of balance to OREO and other	(1,226)	(2,918)
Loans charged off	(706)	(885)
Recoveries	423	377
Allowance for loan losses at end of period	5,531	8,051
Reserve for unfunded commitments
Allowance on loans individually evaluated for impairment	0	16
Allowance on loans collectively evaluated for impairment	5,531	8,035
Loans, net of unearned income:
Loans, net of unearned income	456,062	621,346
Balance at end of period individually evaluated for impairment	679	456
Balance at end of period collectively evaluated for impairment	354,801	493,032
Covered Loans | Consumer and Other Loans | Receivables Acquired With Deteriorated Credit Quality
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	$ 100,582	$ 127,858

Allowance for Credit Losses a62

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, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	$ (20,900)	$ (18,700)
Non-covered loans, net of unearned income	14,722,288	14,098,211
Legacy Loans
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	12,413,370	11,190,520
Legacy Loans | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	9,119,234	8,133,341
Legacy Loans | Commercial Loans | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	8,623,667	7,884,470
Legacy Loans | Commercial Loans | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	122,515	104,800
Legacy Loans | Commercial Loans | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	350,307	132,593
Legacy Loans | Commercial Loans | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	22,745	11,478
Legacy Loans | Commercial Loans | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	696,127	636,481
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	694,983	634,889
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	84	160
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	1,060	1,432
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Legacy Loans | Commercial Loans | Commercial Real Estate - Construction | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Legacy Loans | Commercial Loans | Commercial Real Estate - Other
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	4,723,356	3,867,581
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	4,654,619	3,806,528
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	22,919	21,877
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	45,656	37,001
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	162	2,175
Legacy Loans | Commercial Loans | Commercial Real Estate - Other | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Legacy Loans | Commercial Loans | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	3,101,472	2,952,102
Legacy Loans | Commercial Loans | Commercial and Industrial | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	2,994,661	2,911,396
Legacy Loans | Commercial Loans | Commercial and Industrial | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	34,249	14,826
Legacy Loans | Commercial Loans | Commercial and Industrial | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	53,951	19,888
Legacy Loans | Commercial Loans | Commercial and Industrial | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	18,611	5,992
Legacy Loans | Commercial Loans | Commercial and Industrial | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Legacy Loans | Commercial Loans | Energy-Related
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	598,279	677,177
Legacy Loans | Commercial Loans | Energy-Related | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	279,404	531,657
Legacy Loans | Commercial Loans | Energy-Related | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	65,263	67,937
Legacy Loans | Commercial Loans | Energy-Related | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	249,640	74,272
Legacy Loans | Commercial Loans | Energy-Related | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	3,972	3,311
Legacy Loans | Commercial Loans | Energy-Related | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Legacy Loans | Residential and Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	3,294,136	3,057,179
Current	3,246,299	3,021,225
30+ Days Past Due	47,837	35,954
Legacy Loans | Residential Mortgage | Residential Mortgage
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	840,082	694,023
Current	817,154	676,347
30+ Days Past Due	22,928	17,676
Legacy Loans | Consumer | Consumer - Home Equity
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	1,755,295	1,575,643
Current	1,740,001	1,565,596
30+ Days Past Due	15,294	10,047
Legacy Loans | Consumer | Consumer - Indirect Automobile
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	153,904	246,214
Current	150,008	242,328
30+ Days Past Due	3,896	3,886
Legacy Loans | Consumer | Consumer - Credit Card
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	80,452	77,261
Current	79,588	76,360
30+ Days Past Due	864	901
Legacy Loans | Consumer | Consumer - Other
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	464,403	464,038
Current	459,548	460,594
30+ Days Past Due	4,855	3,444
Acquired Loans
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	2,511,129	3,136,908
Acquired Loans | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(44,654)	(60,088)
Non-covered loans, net of unearned income	1,624,619	2,065,514
Acquired Loans | Commercial Loans | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	1,571,826	1,975,355
Acquired Loans | Commercial Loans | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	28,087	36,192
Acquired Loans | Commercial Loans | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	66,551	104,602
Acquired Loans | Commercial Loans | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	2,786	9,299
Acquired Loans | Commercial Loans | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	23	154
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	11,605	10,107
Non-covered loans, net of unearned income	80,795	125,426
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	63,139	104,064
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	140	1,681
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	5,167	8,803
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	744	771
Acquired Loans | Commercial Loans | Commercial Real Estate - Construction | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Acquired Loans | Commercial Loans | Commercial Real Estate - Other
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(35,184)	(63,295)
Non-covered loans, net of unearned income	1,180,937	1,444,023
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	1,145,942	1,395,884
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	21,731	26,080
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	46,941	79,119
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	1,484	6,124
Acquired Loans | Commercial Loans | Commercial Real Estate - Other | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	23	111
Acquired Loans | Commercial Loans | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(21,068)	(6,900)
Non-covered loans, net of unearned income	361,525	492,476
Acquired Loans | Commercial Loans | Commercial and Industrial | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	361,376	473,241
Acquired Loans | Commercial Loans | Commercial and Industrial | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	6,216	8,376
Acquired Loans | Commercial Loans | Commercial and Industrial | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	14,443	16,510
Acquired Loans | Commercial Loans | Commercial and Industrial | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	558	1,206
Acquired Loans | Commercial Loans | Commercial and Industrial | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	43
Acquired Loans | Commercial Loans | Energy-Related
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(7)	0
Non-covered loans, net of unearned income	1,362	3,589
Acquired Loans | Commercial Loans | Energy-Related | Pass
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	1,369	2,166
Acquired Loans | Commercial Loans | Energy-Related | Special Mention
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	55
Acquired Loans | Commercial Loans | Energy-Related | Substandard
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	170
Acquired Loans | Commercial Loans | Energy-Related | Doubtful
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	1,198
Acquired Loans | Commercial Loans | Energy-Related | Loss
Financing Receivable, Allowance for Credit Losses
Credit quality indicator by asset risk classification	0	0
Acquired Loans | Residential and Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(57,358)	(60,768)
Non-covered loans, net of unearned income	886,510	1,071,394
Current	908,959	1,089,542
30+ Days Past Due	34,909	42,620
Acquired Loans | Residential Mortgage | Residential Mortgage
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(32,795)	(29,559)
Non-covered loans, net of unearned income	430,448	501,296
Current	441,411	506,103
30+ Days Past Due	21,832	24,752
Acquired Loans | Consumer | Consumer - Home Equity
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(24,164)	(29,492)
Non-covered loans, net of unearned income	395,835	490,524
Current	408,541	503,635
30+ Days Past Due	11,458	16,381
Acquired Loans | Consumer | Consumer - Indirect Automobile
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(1)	0
Non-covered loans, net of unearned income	9	84
Current	9	72
30+ Days Past Due	1	12
Acquired Loans | Consumer | Consumer - Credit Card
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	507	582
Acquired Loans | Consumer | Consumer - Other
Financing Receivable, Allowance for Credit Losses
Premium (Discount)	(398)	(1,717)
Non-covered loans, net of unearned income	60,218	79,490
Current	58,998	79,732
30+ Days Past Due	1,618	1,475
Acquired Loans | Consumer | Consumer - Other
Financing Receivable, Allowance for Credit Losses
Non-covered loans, net of unearned income	$ 59,711	$ 78,908

Allowance for Credit Losses a63

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Financing Receivable, Impaired
Acquired Impaired Loans	$ 356,021		$ 356,021		$ 102,733
Unpaid principal balance	342,043		342,043		89,516
Related allowance	(25,306)		(25,306)		(4,123)
Average recorded investment	356,776	$ 77,030	334,058	$ 75,501
Interest income recognized	3,044	327	9,121	933
Commercial Loans
Financing Receivable, Impaired
Acquired Impaired Loans	315,357		315,357		73,846
Unpaid principal balance	304,850		304,850		63,944
Related allowance	(24,068)		(24,068)		(3,655)
Average recorded investment	320,919	53,351	299,334	51,078
Interest income recognized	2,822	324	8,417	929
Residential Mortgage
Financing Receivable, Impaired
Acquired Impaired Loans	18,205		18,205		14,806
Unpaid principal balance	16,840		16,840		13,743
Related allowance	(124)		(124)		(64)
Average recorded investment	16,558	15,008	16,410	15,100
Interest income recognized	49	0	177	0
Consumer
Financing Receivable, Impaired
Acquired Impaired Loans	22,459		22,459		14,081
Unpaid principal balance	20,353		20,353		11,829
Related allowance	(1,114)		(1,114)		(404)
Average recorded investment	19,299	8,671	18,314	9,323
Interest income recognized	173	3	527	4
With No Related Allowance Recorded | Commercial Loans | Commercial real estate
Financing Receivable, Impaired
Acquired Impaired Loans	15,447		15,447		17,002
Unpaid principal balance	14,655		14,655		16,145
Average recorded investment	20,345	16,018	20,633	16,036
Interest income recognized	220	37	663	79
With No Related Allowance Recorded | Commercial Loans | Commercial and Industrial
Financing Receivable, Impaired
Acquired Impaired Loans	29,162		29,162		14,571
Unpaid principal balance	28,722		28,722		14,340
Average recorded investment	29,533	20,055	30,772	20,630
Interest income recognized	313	159	1,030	465
With No Related Allowance Recorded | Commercial Loans | Energy-Related
Financing Receivable, Impaired
Acquired Impaired Loans	168,723		168,723		0
Unpaid principal balance	163,156		163,156		0
Average recorded investment	165,459	3,409	149,099	3,425
Interest income recognized	1,364	0	3,755	0
With No Related Allowance Recorded | Residential Mortgage | Residential Mortgage
Financing Receivable, Impaired
Acquired Impaired Loans	0		0		0
Unpaid principal balance	0		0		0
Average recorded investment	0	0	0	0
Interest income recognized	0	0	0	0
With No Related Allowance Recorded | Consumer | Consumer - Home Equity
Financing Receivable, Impaired
Acquired Impaired Loans	0		0		730
Unpaid principal balance	0		0		730
Average recorded investment	0	215	0	204
Interest income recognized	0	3	0	4
With No Related Allowance Recorded | Consumer | Consumer - Other
Financing Receivable, Impaired
Acquired Impaired Loans	0		0		66
Unpaid principal balance	0		0		66
With An Allowance Recorded | Commercial Loans | Commercial real estate
Financing Receivable, Impaired
Acquired Impaired Loans	17,870		17,870		21,377
Unpaid principal balance	17,843		17,843		13,753
Related allowance	(660)		(660)		(1,253)
Average recorded investment	17,776	11,649	17,654	8,247
Interest income recognized	143	128	433	385
With An Allowance Recorded | Commercial Loans | Commercial and Industrial
Financing Receivable, Impaired
Acquired Impaired Loans	31,406		31,406		7,422
Unpaid principal balance	31,067		31,067		6,262
Related allowance	(9,012)		(9,012)		(277)
Average recorded investment	31,859	2,121	39,087	2,634
Interest income recognized	366	0	1,211	0
With An Allowance Recorded | Commercial Loans | Energy-Related
Financing Receivable, Impaired
Acquired Impaired Loans	52,749		52,749		13,474
Unpaid principal balance	49,407		49,407		13,444
Related allowance	(14,396)		(14,396)		(2,125)
Average recorded investment	55,947	99	42,089	106
Interest income recognized	416	0	1,325	0
With An Allowance Recorded | Residential Mortgage | Residential Mortgage
Financing Receivable, Impaired
Acquired Impaired Loans	18,205		18,205		14,806
Unpaid principal balance	16,840		16,840		13,743
Related allowance	(124)		(124)		(64)
Average recorded investment	16,558	15,008	16,410	15,100
Interest income recognized	49	0	177	0
With An Allowance Recorded | Consumer | Consumer - Home Equity
Financing Receivable, Impaired
Acquired Impaired Loans	16,845		16,845		9,486
Unpaid principal balance	15,615		15,615		8,559
Related allowance	(855)		(855)		(363)
Average recorded investment	14,632	5,344	13,696	5,462
Interest income recognized	119	0	348	0
With An Allowance Recorded | Consumer | Consumer - Indirect Automobile
Financing Receivable, Impaired
Acquired Impaired Loans	2,465		2,465		1,955
Unpaid principal balance	1,727		1,727		1,181
Related allowance	(128)		(128)		(10)
Average recorded investment	1,853	1,361	2,092	1,551
Interest income recognized	16	0	70	0
With An Allowance Recorded | Consumer | Consumer - Credit Card
Financing Receivable, Impaired
Acquired Impaired Loans	438		438		394
Unpaid principal balance	438		438		394
Related allowance	(9)		(9)		(8)
Average recorded investment	468	721	461	1,038
Interest income recognized	0	0	0	0
With An Allowance Recorded | Consumer | Consumer - Other
Financing Receivable, Impaired
Acquired Impaired Loans	2,711		2,711		1,450
Unpaid principal balance	2,573		2,573		899
Related allowance	(122)		(122)		$ (23)
Average recorded investment	2,346	1,030	2,065	1,068
Interest income recognized	$ 38	$ 0	$ 109	$ 0

Loss Sharing Agreements and F64

Loss Sharing Agreements and FDIC Loss Share Receivable (Detail) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016USD ($)acquisition	Sep. 30, 2016USD ($)Businessacquisition	Dec. 31, 2021acquisition	Dec. 31, 2020acquisition	Dec. 31, 2019acquisition	Dec. 31, 2015USD ($)acquisition	Dec. 31, 2014USD ($)acquisition	Sep. 30, 2015USD ($)
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%	95.00%
Loss Sharing Agreements and FDIC Loss Share Receivable [Line Items]
Number of acquisitions exceeding loan loss contractual threshold		3
Recovery period for covered assets		3 years
FDIC loss share receivables | $	$ 24,406	$ 24,406				$ 39,878	$ 69,627	$ 43,443
Excluding Single Family
Loss Sharing Agreements and FDIC Loss Share Receivable [Line Items]
Number of acquisitions exceeding loan loss contractual threshold	2					1	3
Forecast | Single Family
Loss Sharing Agreements and FDIC Loss Share Receivable [Line Items]
Number of acquisitions exceeding loan loss contractual threshold			2	1	3

Loss Sharing Agreements and F65

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
FDIC Indemnification Asset [Roll Forward]
Balance at beginning of period			$ 39,878	$ 69,627
Reversal of loan loss provision recorded on FDIC covered loans			(1,240)	(1,342)
Amortization	$ (3,935)	$ (5,600)	(12,484)	(19,011)
Submission of reimbursable losses to the FDIC			(1,760)	(4,084)
Changes in cash flow assumptions on OREO and other adjustments			12	(1,747)
Balance at end of period	$ 24,406	$ 43,443	$ 24,406	$ 43,443

Goodwill and Other Intangible66

Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Title plant assets	$ 6.7	$ 6.7

Goodwill and Other Intangible67

Goodwill and Other Intangible Assets - Schedule of Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Beginning balance	$ 724,603	$ 517,526
Goodwill adjustments during the period	2,253	207,077
Ending balance	726,856	724,603
IBERIABANK
Goodwill [Roll Forward]
Beginning balance	696,260	489,183
Goodwill adjustments during the period	2,253	207,077
Ending balance	698,513	696,260
IMC
Goodwill [Roll Forward]
Beginning balance	23,178	23,178
Goodwill adjustments during the period	0	0
Ending balance	23,178	23,178
LTC
Goodwill [Roll Forward]
Beginning balance	5,165	5,165
Goodwill adjustments during the period	0	0
Ending balance	$ 5,165	$ 5,165

Goodwill and Other Intangible68

Goodwill and Other Intangible Assets - Schedule of Mortgage Servicing Rights at Carrying Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets
Gross carrying amount	$ 75,411	$ 75,654
Accumulated amortization	(51,159)	(45,134)
Net carrying amount	24,252	30,520
Mortgage Servicing Rights
Acquired Finite-Lived Intangible Assets
Gross carrying amount	6,295	6,104
Accumulated amortization	(2,945)	(2,320)
Net carrying amount	$ 3,350	$ 3,784

Goodwill and Other Intangible69

Goodwill and Other Intangible Assets - Schedule of Definite-Lived Intangible Assets at Carrying Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets
Gross carrying amount	$ 75,411	$ 75,654
Accumulated amortization	(51,159)	(45,134)
Net carrying amount	24,252	30,520
Core Deposit Intangibles
Acquired Finite-Lived Intangible Assets
Gross carrying amount	74,001	74,001
Accumulated amortization	(50,128)	(43,957)
Net carrying amount	23,873	30,044
Customer Relationships Intangible Asset
Acquired Finite-Lived Intangible Assets
Gross carrying amount	1,348	1,348
Accumulated amortization	(1,013)	(984)
Net carrying amount	335	364
Non-Compete Agreements
Acquired Finite-Lived Intangible Assets
Gross carrying amount	62	100
Accumulated amortization	(18)	(79)
Net carrying amount	44	21
Other Intangible Assets
Acquired Finite-Lived Intangible Assets
Gross carrying amount	0	205
Accumulated amortization	0	(114)
Net carrying amount	$ 0	$ 91

Derivative Instruments and Ot70

Derivative Instruments and Other Hedging Activities - Schedule of Outstanding Derivative Instruments (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Fair Value of Derivatives
Derivative assets	$ 55,804	$ 30,486
Derivative liabilities	58,939	24,939
Notional Amount of Derivatives
Derivative assets	1,434,891	1,255,277
Derivative liabilities	1,662,508	950,105
Cash as collateral for derivative transactions	58,000	20,100
Designated as Hedging Instrument
Fair Value of Derivatives
Derivative assets	0	58
Derivative liabilities	9,649	0
Notional Amount of Derivatives
Derivative assets	0	108,500
Derivative liabilities	108,500	0
Designated as Hedging Instrument | Interest Rate Contracts
Notional Amount of Derivatives
Derivative assets	0	108,500
Derivative liabilities	108,500	0
Designated as Hedging Instrument | Interest Rate Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	0	58
Designated as Hedging Instrument | Interest Rate Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	9,649	0
Not Designated as Hedging Instruments
Fair Value of Derivatives
Derivative assets	55,804	30,428
Derivative liabilities	49,290	24,939
Notional Amount of Derivatives
Derivative assets	1,434,891	1,146,777
Derivative liabilities	1,554,008	950,105
Not Designated as Hedging Instruments | Interest Rate Contracts
Notional Amount of Derivatives
Derivative assets	976,456	590,334
Derivative liabilities	976,456	590,334
Not Designated as Hedging Instruments | Interest Rate Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	39,438	18,077
Not Designated as Hedging Instruments | Interest Rate Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	39,563	18,077
Not Designated as Hedging Instruments | Foreign Exchange Contracts
Notional Amount of Derivatives
Derivative assets	4,644	4,392
Derivative liabilities	4,644	4,392
Not Designated as Hedging Instruments | Foreign Exchange Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	44	156
Not Designated as Hedging Instruments | Foreign Exchange Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	30	134
Not Designated as Hedging Instruments | Forward Sales Contracts
Notional Amount of Derivatives
Derivative assets	53,662	223,841
Derivative liabilities	405,697	173,430
Not Designated as Hedging Instruments | Forward Sales Contracts | Other Assets
Fair Value of Derivatives
Derivative assets	105	1,588
Not Designated as Hedging Instruments | Forward Sales Contracts | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	1,680	474
Not Designated as Hedging Instruments | Written and Purchased Options
Notional Amount of Derivatives
Derivative assets	400,129	328,210
Derivative liabilities	167,211	181,949
Not Designated as Hedging Instruments | Written and Purchased Options | Other Assets
Fair Value of Derivatives
Derivative assets	16,217	10,607
Not Designated as Hedging Instruments | Written and Purchased Options | Other Liabilities
Fair Value of Derivatives
Derivative liabilities	$ 8,017	$ 6,254

Derivative Instruments and Ot71

Derivative Instruments and Other Hedging Activities - Reconciliation of Gross Amounts in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivative assets
Gross Amounts Presented in the Balance Sheet	$ 47,436	$ 24,393
Gross amounts not offset in the Balance Sheet, derivatives	0	0
Gross amounts not offset in the Balance Sheet, collateral	0	0
Net	47,436	24,393
Derivative liabilities
Gross Amounts Presented in the Balance Sheet	49,212	18,058
Gross amounts not offset in the Balance Sheet, derivatives	0	0
Gross amounts not offset in the Balance Sheet, collateral	(57,999)	(20,104)
Net	(8,787)	(2,046)
Written and Purchased Options
Derivative assets
Gross Amounts Presented in the Balance Sheet	7,998	6,277
Gross amounts not offset in the Balance Sheet, derivatives	0	0
Gross amounts not offset in the Balance Sheet, collateral	0	0
Net	7,998	6,277
Designated as Hedging Instrument | Interest Rate Contracts
Derivative assets
Gross Amounts Presented in the Balance Sheet		58
Gross amounts not offset in the Balance Sheet, derivatives		0
Gross amounts not offset in the Balance Sheet, collateral		0
Net		58
Derivative liabilities
Gross Amounts Presented in the Balance Sheet	9,649
Gross amounts not offset in the Balance Sheet, derivatives	0
Gross amounts not offset in the Balance Sheet, collateral	(12,752)
Net	(3,103)
Not Designated as Hedging Instruments | Interest Rate Contracts
Derivative assets
Gross Amounts Presented in the Balance Sheet	39,438	18,058
Gross amounts not offset in the Balance Sheet, derivatives	0	0
Gross amounts not offset in the Balance Sheet, collateral	0	0
Net	39,438	18,058
Derivative liabilities
Gross Amounts Presented in the Balance Sheet	39,563	18,058
Gross amounts not offset in the Balance Sheet, derivatives	0	0
Gross amounts not offset in the Balance Sheet, collateral	(45,247)	(20,104)
Net	$ (5,684)	$ (2,046)

Derivative Instruments and Ot72

Derivative Instruments and Other Hedging Activities - Effect of Derivatives on Consolidated Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in Income on Derivatives	$ (2,995)	$ (5,920)	$ (1,358)	$ 2,884
Not Designated as Hedging Instruments | Interest Rate Contracts | Other Income
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in Income on Derivatives	2,215	1,130	7,509	3,069
Not Designated as Hedging Instruments | Foreign Exchange Contracts | Other Income
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in Income on Derivatives	4	0	7	0
Not Designated as Hedging Instruments | Forward Sales Contracts | Mortgage Income
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in Income on Derivatives	(2,590)	(6,524)	(12,720)	1,526
Not Designated as Hedging Instruments | Written and Purchased Options | Mortgage Income
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in Income on Derivatives	(2,624)	(526)	3,846	(1,711)
Cash Flow Hedging | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in OCI net of taxes (Effective Portion)	146	(3,412)	(6,309)	(374)
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	0	0	0
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	0	0	0	0
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Contracts
Derivative Instruments, Gain (Loss)
Amount of Gain (Loss) Recognized in OCI net of taxes (Effective Portion)	146	(3,412)	(6,309)	(374)
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 (Effective Portion)	0	0	0	0
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ 0	$ 0	$ 0	$ 0

Shareholders' Equity, Capital73

Shareholders' Equity, Capital Ratios and Other Regulatory Matters (Details) - USD ($) $ / shares in Units, $ in Thousands	May 09, 2016	May 04, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Class of Stock
Percent of trust based securities excluded from tier one risk based capital			100.00%
Preferred stock, par value (in usd per share)			$ 1		$ 1
Liquidation preference (in usd per share)			$ 10,000		$ 10,000
Number of shares authorized for repurchase		950,000
Period of share repurchase program		2 years
Shares repurchases (in shares)			0	202,506
Average cost of shares repurchased (in dollars per share)				$ 57.61
Consolidated
Class of Stock
Capital conversion buffer (percent)			4.49%
IBERIABANK
Class of Stock
Capital conversion buffer (percent)			3.44%
Depository Shares [Member]
Class of Stock
Shares issued	2,300,000
Liquidation preference equivalent (in usd per share)	$ 25
Liquidation preference	$ 57,500
Series C Preferred Stock [Member]
Class of Stock
Dividend rate (percentage)	6.60%
Preferred stock, par value (in usd per share)	$ 1
Liquidation preference (in usd per share)	$ 10,000
LIBOR | Series C Preferred Stock [Member]
Class of Stock
Variable dividend rate beginning on May 1, 2026	492.00%

Shareholders' Equity, Capital74

Shareholders' Equity, Capital Ratios and Other Regulatory Matters - Actual Capital Amounts and Ratios (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Consolidated
Tier 1 Leverage
Minimum amount	$ 784,103	$ 751,798
Minimum ratio	4.00%	4.00%
Actual amount	$ 1,901,866	$ 1,790,034
Actual ratio	9.70%	9.52%
Common Equity Tier 1 (CET1)
Minimum amount	$ 785,140	$ 752,610
Minimum ratio	4.50%	4.50%
Actual amount	$ 1,769,769	$ 1,684,097
Actual ratio	10.14%	10.07%
Tier 1 Risk-Based Capital
Minimum amount	$ 1,046,854	$ 1,003,479
Minimum ratio	6.00%	6.00%
Actual amount	$ 1,901,866	$ 1,790,034
Actual ratio	10.90%	10.70%
Total Risk-Based Capital
Minimum amount	$ 1,395,805	$ 1,337,973
Minimum ratio	8.00%	8.00%
Actual amount	$ 2,178,549	$ 2,029,932
Actual ratio	12.49%	12.14%
IBERIABANK
Tier 1 Leverage
Minimum amount	$ 781,582	$ 749,226
Minimum ratio	4.00%	4.00%
Well capitalized amount	$ 976,978	$ 936,532
Well capitalized ratio	5.00%	5.00%
Actual amount	$ 1,831,469	$ 1,691,022
Actual ratio	9.37%	9.03%
Common Equity Tier 1 (CET1)
Minimum amount	$ 783,333	$ 750,660
Minimum ratio	4.50%	4.50%
Well capitalized amount	$ 1,131,481	$ 1,084,287
Well capitalized ratio	6.50%	6.50%
Actual amount	$ 1,831,469	$ 1,691,022
Actual ratio	10.52%	10.14%
Tier 1 Risk-Based Capital
Minimum amount	$ 1,044,444	$ 1,000,880
Minimum ratio	6.00%	6.00%
Well capitalized amount	$ 1,392,591	$ 1,334,507
Well capitalized ratio	8.00%	8.00%
Actual amount	$ 1,831,469	$ 1,691,022
Actual ratio	10.52%	10.14%
Total Risk-Based Capital
Minimum amount	$ 1,392,591	$ 1,334,507
Minimum ratio	8.00%	8.00%
Well capitalized amount	$ 1,740,739	$ 1,668,133
Well capitalized ratio	10.00%	10.00%
Actual amount	$ 1,991,651	$ 1,843,545
Actual ratio	11.44%	11.05%

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings per common share - basic
Net Income	$ 48,068	$ 42,475	$ 141,647	$ 98,437
Preferred stock dividends	(3,590)	0	(7,020)	0
Dividends and undistributed earnings allocated to unvested restricted shares	(462)	(492)	(1,464)	(1,171)
Earnings Allocated to Common Shareholders - Basic	$ 44,016	$ 41,983	$ 133,163	$ 97,266
Weighted average common shares outstanding (in shares)	40,618	40,514	40,699	37,436
Earnings per common share - Basic (in usd per share)	$ 1.08	$ 1.04	$ 3.27	$ 2.60
Earnings per common share - diluted
Earnings Allocated to Common Shareholders - Basic	$ 44,016	$ 41,983	$ 133,163	$ 97,266
Dividends and undistributed earnings allocated to unvested restricted shares	(4)	(3)	(17)	(41)
Earnings allocated to common shareholders - diluted	$ 44,012	$ 41,980	$ 133,146	$ 97,225
Weighted average common shares outstanding (in shares)	40,618	40,514	40,699	37,436
Dilutive potential common shares - stock options (in shares)	193	100	119	96
Weighted average common shares outstanding - diluted (in shares)	40,811	40,614	40,818	37,532
Earnings per common share - Diluted (in usd per share)	$ 1.08	$ 1.03	$ 3.26	$ 2.59

Earnings Per Share - Antidiluti

Earnings Per Share - Antidilutive Securities (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Recognition and Retention Plan Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options having antidilutive effect on earnings per share	434,468	616,307	456,921	606,621
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options having antidilutive effect on earnings per share	73,882	82,310	268,257	79,690

Share-Based Compensation (Detai

Share-Based Compensation (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award
Future awards shares under approved incentive compensation plans	2,468,506
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Share-based compensation maximum option term	10 years
Unearned share-based compensation associated with awards	$ 2.5
Unrecognized compensation cost expected to be recognized over a weighted-average period	2 years 5 months
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award
Unearned share-based compensation associated with awards	$ 18.3	$ 22.2
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Performance period	3 years
Phantom Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period	5 years
Phantom Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period	7 years

Share-Based Compensation - Acti

Share-Based Compensation - Activity Related to Stock Options (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Number of shares
Beginning balance (in shares)	813,777	867,682
Granted (in shares)	152,209	81,313
Exercised (in shares)	(72,258)	(95,265)
Forfeited or expired (in shares)	(49,636)	(15,733)
Ending balance (in shares)	844,092	837,997
Exercisable options (in shares)	538,751	570,148
Weighted Average Exercise Price
Beginning balance (in usd per share)	$ 56.99	$ 55.92
Granted (in usd per share)	47.63	62.53
Exercised (in usd per share)	55.28	50.64
Forfeited or expired (in usd per share)	60.06	66.57
Ending balance (in usd per share)	55.27	56.96
Exercisable options (in usd per share)	$ 56.40	$ 56.53

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, 2016	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected dividends	2.90%	2.20%
Expected volatility	29.10%	35.60%
Risk-free interest rate	1.40%	2.00%
Expected term	6 years 6 months	7 years 6 months
Weighted-average grant-date fair value	$ 10.16	$ 19.60

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Compensation expense	$ 513	$ 455	$ 1,500	$ 1,400
Restricted Stock Awards and Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award
Compensation expense	3,014	2,935	9,729	8,739
Phantom Stock and Performance Units
Share-based Compensation Arrangement by Share-based Payment Award
Compensation expense	$ 3,127	$ 2,976	$ 8,325	$ 9,482

Share-Based Compensation - Unve

Share-Based Compensation - Unvested Restricted Stock Award and Restricted Share Unit Activity (Detail) - shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares)	507,130	506,289
Granted (in shares)	244,074	203,762
Forfeited (in shares)	(16,890)	(23,471)
Earned and issued (in shares)	(184,873)	(170,513)
Ending balance (in shares)	549,441	516,067

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, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Total Share Equivalents [Roll Forward]
Beginning balance (in shares)	462,430	475,347
Granted (in shares)	200,761	162,740
Forfeited share equivalents (in shares)	(27,267)	(28,728)
Vested share equivalents (in shares)	(158,491)	(138,678)
Ending balance (in shares)	477,433	470,681
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Value of Share Equivalents [Roll Forward]
Beginning balance	$ 25,466	$ 30,826
Granted	13,475	9,473
Forfeited share equivalents	1,830	1,672
Vested share equivalents	8,161	8,832
Ending balance	$ 32,045	$ 27,398
Market price of Company's stock (in usd per share)	$ 67.12	$ 58.21

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Securities available for sale	$ 2,885,413	$ 2,800,286
Mortgage loans held for sale	210,866	166,247
Derivative instruments	47,436	24,393
Liabilities
Derivative instruments	49,212	18,058
Level 1
Assets
Derivative instruments	0	0
Liabilities
Derivative instruments	0	0
Level 2
Assets
Derivative instruments	55,804	30,486
Liabilities
Derivative instruments	58,939	24,939
Level 3
Assets
Derivative instruments	0	0
Liabilities
Derivative instruments	0	0
Recurring
Assets
Securities available for sale	2,885,413	2,800,286
Mortgage loans held for sale	210,866	166,247
Derivative instruments	55,804	30,486
Total	3,152,083	2,997,019
Liabilities
Derivative instruments	58,939	24,939
Total	58,939	24,939
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
Total	0	0
Recurring | Level 2
Assets
Securities available for sale	2,885,413	2,800,286
Mortgage loans held for sale	210,866	166,247
Derivative instruments	55,804	30,486
Total	3,152,083	2,997,019
Liabilities
Derivative instruments	58,939	24,939
Total	58,939	24,939
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
Total	$ 0	$ 0

Fair Value Measurements - Fin84

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Fair value of impaired loans	$ 342,043	$ 89,516
Loan reserves and charge-offs	25,306	4,123
Nonrecurring
Assets
Loans	85,463	31,669
OREO, net	405	1,662
Total	85,868	33,331
Nonrecurring | Level 1
Assets
Loans	0	0
OREO, net	0	0
Total	0	0
Nonrecurring | Level 2
Assets
Loans	0	0
OREO, net	0	0
Total	0	0
Nonrecurring | Level 3
Assets
Loans	85,463	31,669
OREO, net	405	1,662
Total	85,868	33,331
Fair Value
Assets
Fair value of impaired loans	120,600	40,200
Loan reserves and charge-offs	$ 35,200	$ 8,500

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Aggregate fair value	$ 210,866		$ 210,866		$ 166,247
Aggregate unpaid principal	203,293		203,293		161,083
Aggregate fair value less unpaid principal	7,573		7,573		$ 5,164
Net gain (loss) on change in Fair Value	$ (1,500)	$ 7	$ 2,400	$ 3,700

Fair Value of Financial Instr86

Fair Value of Financial Instruments - Estimated Fair Values and Carrying Amounts of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Financial Assets
Cash and cash equivalents	$ 1,101,253	$ 510,267	$ 682,272	$ 548,095
Loans and loans held for sale, net of unearned income and allowance for loan losses	15,135,365		14,319,187
FDIC loss share receivables	24,406	39,878	43,443	$ 69,627
Derivative instruments	47,436	24,393
Financial Liabilities
Deposits	16,522,517	16,178,748	$ 16,303,065
Short-term borrowings	713,272	326,617
Long-term debt	672,438	340,447
Derivative instruments	49,212	18,058
Level 1
Financial Assets
Cash and cash equivalents	1,101,253	510,267
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	353,272	216,617
Long-term debt	0	0
Derivative instruments	0	0
Level 2
Financial Assets
Cash and cash equivalents	0	0
Investment securities	2,978,823	2,901,247
Loans and loans held for sale, net of unearned income and allowance for loan losses	210,866	166,247
FDIC loss share receivables	0	0
Derivative instruments	55,804	30,486
Financial Liabilities
Deposits	0	0
Short-term borrowings	360,000	110,000
Long-term debt	0	0
Derivative instruments	58,939	24,939
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	14,822,094	14,508,502
FDIC loss share receivables	6,343	9,163
Derivative instruments	0	0
Financial Liabilities
Deposits	16,485,224	15,696,245
Short-term borrowings	0	0
Long-term debt	660,140	309,847
Derivative instruments	0	0
Carrying Amount
Financial Assets
Cash and cash equivalents	1,101,253	510,267
Investment securities	2,976,066	2,899,214
Loans and loans held for sale, net of unearned income and allowance for loan losses	14,987,172	14,355,297
FDIC loss share receivables	24,406	39,878
Derivative instruments	55,804	30,486
Financial Liabilities
Deposits	16,522,517	16,178,748
Short-term borrowings	713,272	326,617
Long-term debt	672,438	340,447
Derivative instruments	58,939	24,939
Fair Value
Financial Assets
Cash and cash equivalents	1,101,253	510,267
Investment securities	2,978,823	2,901,247
Loans and loans held for sale, net of unearned income and allowance for loan losses	15,032,960	14,674,749
FDIC loss share receivables	6,343	9,163
Derivative instruments	55,804	30,486
Financial Liabilities
Deposits	16,485,224	15,696,245
Short-term borrowings	713,272	326,617
Long-term debt	660,140	309,847
Derivative instruments	$ 58,939	$ 24,939

Business Segments (Detail)

Business Segments (Detail)	9 Months Ended
	Sep. 30, 2016Segment
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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information
Interest and dividend income	$ 180,504	$ 171,077	$ 536,134	$ 470,207
Interest expense	17,087	15,960	48,561	43,609
Net interest income	163,417	155,117	487,573	426,598
Provision for loan losses	12,484	5,062	39,255	19,197
Mortgage income	21,807	20,628	67,738	63,897
Service charges on deposit accounts	11,066	11,342	32,957	30,766
Title revenue	6,001	6,627	16,881	17,402
Other non-interest income	20,947	18,881	63,007	55,825
Allocated expenses	0	0	0	0
Non-interest expense	138,139	144,968	415,095	431,330
Income before income tax expense	72,615	62,565	213,806	143,961
Income tax expense	24,547	20,090	72,159	45,524
Net Income	48,068	42,475	141,647	98,437
Total loans and loans held for sale, net of unearned income	15,135,365	14,319,187	15,135,365	14,319,187
Total assets	20,788,566	19,534,225	20,788,566	19,534,225	$ 19,504,068
Total deposits	16,522,517	16,303,065	16,522,517	16,303,065	$ 16,178,748
Average assets	20,392,828	19,604,070	20,020,715	18,015,680
IBERIABANK
Segment Reporting Information
Interest and dividend income	178,521	169,005	530,409	464,775
Interest expense	15,944	15,109	45,380	41,410
Net interest income	162,577	153,896	485,029	423,365
Provision for loan losses	12,443	5,062	39,214	19,197
Mortgage income	850	263	856	830
Service charges on deposit accounts	11,066	11,342	32,957	30,766
Title revenue	0	0	0	0
Other non-interest income	20,946	18,880	62,999	55,834
Allocated expenses	(3,914)	(3,518)	(10,468)	(11,603)
Non-interest expense	127,690	124,909	367,985	373,948
Income before income tax expense	59,220	57,928	185,110	129,253
Income tax expense	19,282	18,253	60,841	39,695
Net Income	39,938	39,675	124,269	89,558
Total loans and loans held for sale, net of unearned income	14,957,337	14,094,936	14,957,337	14,094,936
Total assets	20,537,304	19,242,690	20,537,304	19,242,690
Total deposits	16,513,867	16,293,681	16,513,867	16,293,681
Average assets	20,061,071	19,321,164	19,705,052	17,760,033
IMC
Segment Reporting Information
Interest and dividend income	1,982	2,071	5,723	5,430
Interest expense	1,143	851	3,181	2,199
Net interest income	839	1,220	2,542	3,231
Provision for loan losses	41	0	41	0
Mortgage income	20,957	20,365	66,882	63,067
Service charges on deposit accounts	0	0	0	0
Title revenue	0	0	0	0
Other non-interest income	1	1	8	(2)
Allocated expenses	3,010	2,693	8,007	8,685
Non-interest expense	5,891	15,605	33,909	44,259
Income before income tax expense	12,855	3,288	27,475	13,352
Income tax expense	5,048	1,306	10,826	5,286
Net Income	7,807	1,982	16,649	8,066
Total loans and loans held for sale, net of unearned income	178,028	224,251	178,028	224,251
Total assets	226,906	264,914	226,906	264,914
Total deposits	8,650	9,384	8,650	9,384
Average assets	305,996	256,897	289,037	230,379
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
Service charges on deposit accounts	0	0	0	0
Title revenue	6,001	6,627	16,881	17,402
Other non-interest income	0	0	0	(7)
Allocated expenses	904	825	2,461	2,918
Non-interest expense	4,558	4,454	13,201	13,123
Income before income tax expense	540	1,349	1,221	1,356
Income tax expense	217	531	492	543
Net Income	323	818	729	813
Total loans and loans held for sale, net of unearned income	0	0	0	0
Total assets	24,356	26,621	24,356	26,621
Total deposits	0	0	0	0
Average assets	$ 25,761	$ 26,009	$ 26,626	$ 25,268

Commitments and Contingencies89

Commitments and Contingencies (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Letters of Credit
Other Commitments [Line Items]
Fair value of guarantees under commercial and standby letters of credit	$ 1.7	$ 1.5

Commitments and Contingencies -

Commitments and Contingencies - Summary of Financial Instruments Outstanding (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Loss Contingencies
Reserve for unfunded lending commitments	$ 11,990	$ 14,145	$ 14,525	$ 11,801
Credit Risk Contract
Loss Contingencies
Commitments to grant loans	398,754	61,240
Unfunded commitments under lines of credit	4,876,141	4,617,802
Commercial and standby letters of credit	165,365	150,281
Reserve for unfunded lending commitments	$ 11,990	$ 14,145

Related Party Transactions (Det

Related Party Transactions (Details) - Affiliated Entity - Stone Energy Corporation - Credit Facility	9 Months Ended
	Sep. 30, 2016USD ($)bank	Dec. 31, 2015USD ($)
Related Party Transaction [Line Items]
Number of banks party to facility | bank	12
Federal Funds Rate
Related Party Transaction [Line Items]
Variable rate (percentage)	0.50%
LIBOR
Related Party Transaction [Line Items]
Variable rate (percentage)	1.00%
IBERIABANK
Related Party Transaction [Line Items]
Percent of commitments held under facility	6.00%
Commitments held under facility	$ 21,600,000
Outstanding balance	$ 20,500,000	$ 0