Iberiabank (IBKC) 10-Q 9 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 31, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Trading Symbol	IBKC
Entity Registrant Name	IBERIABANK CORP
Entity Central Index Key	933,141
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		53,627,330

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 301,910	$ 295,896
Interest-bearing deposits in banks	167,450	1,066,230
Total cash and cash equivalents	469,360	1,362,126
Securities available for sale, at fair value	4,009,299	3,446,097
Securities held to maturity (fair values of $85,448 and $89,932, respectively)	84,517	89,216
Mortgage loans held for sale, at fair value	140,959	157,041
Loans, net of unearned income	15,556,016	15,064,971
Allowance for loan losses	(146,225)	(144,719)
Loans, net	15,409,791	14,920,252
Premises and equipment, net	318,167	306,373
Goodwill	726,856	726,856
Other assets	631,778	651,229
Total Assets	21,790,727	21,659,190
Deposits:
Non-interest-bearing	5,020,195	4,928,878
Interest-bearing	11,832,921	12,479,405
Total deposits	16,853,116	17,408,283
Short-term borrowings	583,935	509,136
Long-term debt	667,243	628,953
Other liabilities	183,191	173,124
Total Liabilities	18,287,485	18,719,496
Shareholders’ Equity
Carrying Amount	132,097	132,097
Common stock, $1 par value - 100,000,000 shares authorized; 51,014,880 and 44,795,386 shares issued and outstanding, respectively	51,015	44,795
Additional paid-in capital	2,568,474	2,084,446
Retained earnings	765,582	704,391
Accumulated other comprehensive income (loss)	(13,926)	(26,035)
Total Shareholders’ Equity	3,503,242	2,939,694
Total Liabilities and Shareholders’ Equity	$ 21,790,727	$ 21,659,190

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Securities held to maturity, fair values	$ 85,448	$ 89,932
Preferred stock, par value (in usd per share)	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Liquidation preference (per share)	$ 10,000	$ 10,000
Preferred stock, shares issued	13,750	13,750
Preferred stock, shares outstanding	13,750	13,750
Common stock, par value (in usd per share)	$ 1	$ 1
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	51,014,880	44,795,386
Common stock, shares outstanding	51,014,880	44,795,386

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest and Dividend Income
Loans, including fees	$ 179,266	$ 165,569	$ 348,242	$ 329,560
Mortgage loans held for sale, including fees	1,248	1,850	2,219	3,251
Investment securities:
Taxable interest	20,246	12,994	38,110	26,542
Tax-exempt interest	2,060	1,670	4,124	3,334
Amortization of FDIC loss share receivable	0	(4,163)	0	(8,549)
Other	1,755	774	4,413	1,492
Total interest and dividend income	204,575	178,694	397,108	355,630
Deposits:
NOW and MMDA	12,207	7,310	23,306	14,668
Savings	329	297	649	519
Time deposits	4,576	4,309	9,214	8,663
Short-term borrowings	227	662	504	1,147
Long-term debt	3,593	3,363	6,974	6,477
Total interest expense	20,932	15,941	40,647	31,474
Net interest income	183,643	162,753	356,461	324,156
Provision for loan losses	12,050	11,866	18,204	26,771
Net interest income after provision for loan losses	171,593	150,887	338,257	297,385
Non-interest Income
Mortgage income	19,730	25,991	33,845	45,931
Service charges on deposit accounts	11,410	10,940	22,563	21,891
Title revenue	6,190	6,135	10,931	10,880
Broker commissions	2,744	3,712	5,482	7,535
ATM/debit card fee income	3,800	3,650	7,385	7,153
Credit card and merchant-related income	3,519	2,732	6,746	5,387
Income from bank owned life insurance	1,241	1,411	2,552	2,613
Gain on sale of available for sale securities	59	1,789	59	1,985
Other non-interest income	7,273	8,557	13,749	17,387
Total non-interest income	55,966	64,917	103,312	120,762
Non-interest Expense
Salaries and employee benefits	86,317	85,105	168,170	165,847
Net occupancy and equipment	16,292	16,813	32,313	33,720
Communication and delivery	2,956	3,281	6,000	6,340
Marketing and business development	3,238	3,142	6,662	6,644
Data processing	7,306	6,101	14,247	12,019
Professional services	11,219	4,939	16,553	8,719
Credit and other loan related expense	3,780	2,931	8,306	5,602
Insurance	4,486	4,449	9,016	8,633
Travel and entertainment	2,753	1,938	5,237	4,321
Other non-interest expense	9,161	10,805	22,022	25,111
Total non-interest expense	147,508	139,504	288,526	276,956
Income before income tax expense	80,051	76,300	153,043	141,191
Income tax expense	28,033	25,490	50,552	47,612
Net Income	52,018	50,810	102,491	93,579
Preferred stock dividends	(949)	(854)	(4,548)	(3,430)
Net Income Available to Common Shareholders	51,069	49,956	97,943	90,149
Earnings allocated to unvested restricted stock	(361)	(540)	(707)	(1,003)
Earnings allocated to common shareholders	$ 50,708	$ 49,416	$ 97,236	$ 89,146
Earnings per common share - Basic (in usd per share)	$ 1	$ 1.21	$ 2.01	$ 2.19
Earnings per common share - Diluted (in usd per share)	0.99	1.21	1.99	2.18
Cash dividends declared per common share (in usd per share)	$ 0.36	$ 0.34	$ 0.72	$ 0.68
Comprehensive Income
Net income	$ 52,018	$ 50,810	$ 102,491	$ 93,579
Unrealized gains (losses) on securities:
Unrealized holding gains (losses) arising during the period (net of tax effects of $4,537, $5,313, $6,958, and $19,015, respectively)	8,426	9,867	12,922	35,314
Reclassification adjustment for gains included in net income (net of tax effects of $21, $626, $21, and $695, respectively)	(38)	(1,163)	(38)	(1,290)
Unrealized gains (losses) on securities, net of tax	8,388	8,704	12,884	34,024
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 $426, $1,252, $338, and $3,475, respectively)	(790)	(2,328)	(627)	(6,455)
Reclassification adjustment for gains included in net income (net of tax effects of $55, $0, $80, and $0, respectively)	(103)	0	(148)	0
Fair value of derivative instruments designated as cash flow hedges, net of tax	(893)	(2,328)	(775)	(6,455)
Other comprehensive income (loss), net of tax	7,495	6,376	12,109	27,569
Comprehensive income	$ 59,513	$ 57,186	$ 114,600	$ 121,148

Consolidated Statements of Com5

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Unrealized holding gains (losses), taxes	$ 4,537	$ 5,313
Reclassification adjustment for gains included in net income , taxes	21	626
Change in fair value of derivative instruments designated as cash flow hedges, taxes	426	1,252
Reclassification adjustment for losses included in net income, taxes	$ 55	$ 0

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
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)
Increase (Decrease) in Shareholders' Equity
Net income	93,579				93,579
Other comprehensive income/(loss)	27,569					27,569
Cash dividends declared	(28,016)				(28,016)
Preferred stock dividends	(3,430)				(3,430)
Common stock issued under incentive plans, net of shares surrendered in payment, including tax benefit (in shares)			101,802
Common stock issued under incentive plans, net of shares surrendered in payment	(2,262)		$ 102	(2,364)
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	7,702			7,702
Ending balance (in shares) at Jun. 30, 2016		13,750	41,038,833
Ending balance at Jun. 30, 2016	2,637,596	$ 132,097	$ 41,039	1,791,857	646,619	25,984
Beginning balance (in shares) at Dec. 31, 2016		13,750	44,795,386
Beginning balance at Dec. 31, 2016	2,939,694	$ 132,097	$ 44,795	2,084,446	704,391	(26,035)
Increase (Decrease) in Shareholders' Equity
Net income	102,491				102,491
Other comprehensive income/(loss)	12,109					12,109
Cash dividends declared	(36,752)				(36,752)
Preferred stock dividends	(4,548)				(4,548)
Common stock issued under incentive plans, net of shares surrendered in payment, including tax benefit (in shares)			119,494
Common stock issued under incentive plans, net of shares surrendered in payment	(2,057)		$ 120	(2,177)
Shares issued (in shares)			6,100,000
Common stock issued	485,194		$ 6,100	479,094
Share-based compensation cost	7,111			7,111
Ending balance (in shares) at Jun. 30, 2017		13,750	51,014,880
Ending balance at Jun. 30, 2017	$ 3,503,242	$ 132,097	$ 51,015	$ 2,568,474	$ 765,582	$ (13,926)

Consolidated Statements of Sha7

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash dividends declared per common share (in usd per share)	$ 0.72	$ 0.68
Retained Earnings
Cash dividends declared per common share (in usd per share)	$ 0.72	$ 0.68

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows from Operating Activities
Net income	$ 102,491	$ 93,579
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, and accretion	9,282	3,115
Amortization of purchase accounting and market value adjustments	(20,142)	(8,551)
Provision for loan losses	18,204	26,771
Share-based compensation cost - equity awards	7,111	7,702
(Gain)/loss on sale of assets, net	(44)	3
(Gain)/loss on sale of available for sale securities	(59)	(1,985)
(Gain)/loss on sale of OREO, net	(2,906)	(4,711)
Amortization of premium/discount on securities, net	12,685	10,222
Derivative losses (gain) on swaps	(228)	0
Expense (benefit) for deferred income taxes	10,040	(1,620)
Originations of mortgage loans held for sale	(919,207)	(1,227,825)
Proceeds from sales of mortgage loans held for sale	965,042	1,206,323
Realized and unrealized (gain)/loss on mortgage loans held for sale, net	(33,110)	(45,563)
Other operating activities, net	(2,127)	(11,814)
Net Cash Provided by Operating Activities	147,032	45,646
Cash Flows from Investing Activities
Proceeds from sales of available for sale securities	64,144	197,733
Proceeds from maturities, prepayments and calls of available for sale securities	236,468	215,115
Purchases of available for sale securities	(856,187)	(341,790)
Proceeds from maturities, prepayments and calls of held to maturity securities	4,267	5,603
Purchases of held to maturity securities	0	0
Purchases of equity securities	(1,180)	(31,292)
Proceeds from sales of equity securities	5,059	300
Reimbursement of recoverable covered asset losses (to) from the FDIC	0	(4,234)
Increase in loans, net of loans acquired	(481,482)	(381,367)
Proceeds from sale of premises and equipment	2,365	1,188
Purchases of premises and equipment, net of premises and equipment acquired	(24,001)	(6,518)
Proceeds from disposition of OREO	9,949	20,365
Cash paid for investments in tax credit entities	(2,827)	(5,916)
Other investing activities, net	1,267	(750)
Net Cash Used in Investing Activities	(1,042,158)	(331,563)
Cash Flows from Financing Activities
Increase/(decrease) in deposits, net of deposits acquired	(554,983)	(316,483)
Net change in short-term borrowings, net of borrowings acquired	74,799	439,019
Proceeds from long-term debt	50,000	360,000
Repayments of long-term debt	(11,252)	(12,351)
Cash dividends paid on common stock	(34,476)	(28,006)
Cash dividends paid on preferred stock	(4,548)	(2,576)
Net share-based compensation stock transactions	(2,374)	(2,275)
Payments to repurchase common stock	0	(11,666)
Net proceeds from issuance of common stock	485,194	0
Net proceeds from issuance of preferred stock	0	55,286
Net Cash Provided by Financing Activities	2,360	480,948
Net Increase (Decrease) In Cash and Cash Equivalents	(892,766)	195,031
Cash and Cash Equivalents at Beginning of Period	1,362,126	510,267
Cash and Cash Equivalents at End of Period	469,360	705,298
Supplemental Schedule of Non-cash Activities
Acquisition of real estate in settlement of loans	6,467	3,910
Cash paid for:
Interest on deposits and borrowings	40,778	30,244
Income taxes, net	$ 40,872	$ 54,453

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	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, 2016. Operating results for the period ended June 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017. 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 $94 million and $91 million at June 30, 2017 and December 31, 2016, 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. Effective January 1, 2017, IBERIABANK Mortgage Company, previously a subsidiary of IBERIABANK, merged into IBERIABANK. 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 eight states through IBERIABANK. The Company also operates mortgage production offices in 10 states 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. 840 Denning, LLC invests in a commercial rental property. CDE is engaged in the purchase of tax credits. Reclassifications Certain amounts reported in prior periods have been reclassified to conform to the current period presentation. These reclassifications did not have a material effect on previously reported consolidated financial statements. 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, and income taxes. Concentrations of Credit Risk Most of the Company’s business activity is with customers located in the southeastern United States. 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 higher net worth clients. Repayments on loans are expected to come from cash flows of the borrower and/or guarantor. Losses on secured loans are limited by the net realizable value of the collateral upon default of the borrowers and guarantor support. Concentrations in commercial real estate have increased as a result of the Company's organic growth and recent acquisitions of banks with significant CRE portfolios. Additionally, as the Company has executed its risk-off strategy over the past two years, CRE concentrations have naturally increased as a percentage of the total portfolio. The Company believes it does not have any excessive concentrations to any one industry or customer.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	6 Months Ended
	Jun. 30, 2017
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS Pronouncements adopted during the six months ended June 30, 2017: ASU No. 2016-09 The Company adopted the amendments of ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, effective January 1, 2017 as follows: (i) prospective adoption of the recognition of excess tax benefits associated with awards which vested or settled during the six months ended June 30, 2017 in the statement of comprehensive income; (ii) prospective adoption of the exclusion of excess tax benefits from assumed proceeds for the calculation of diluted EPS for the six months ended June 30, 2017; (iii) modified retrospective adoption of the minimum statutory withholdings requirements; (iv) modified retrospective adoption of the accounting policy election to account for forfeitures as they occur; and (v) prospective adoption of the classifications of certain cash flows associated with stock compensation. The adoption of these amendments did not, either individually or in aggregate, have a significant impact to the consolidated financial statements. ASU No. 2017-01 In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business , which introduces amendments that are intended to clarify the definition of a business to assist companies and other reporting organizations in evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments will be applied prospectively and are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those periods, with early adoption permitted. The Company early-adopted the amendments effective January 1, 2017. The adoption of this ASU did not and is not expected to have a significant impact on the Company’s consolidated financial statements. Pronouncements issued but not yet adopted: ASU No. 2014-09 In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers , which implements a common revenue standard and clarifies the principles used for recognizing revenue. The amendments in the ASU clarify that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in ASU No. 2014-09 will be effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. The amendments will be applied through the election of one of two retrospective methods. The Company will adopt the amendments beginning January 1, 2018 through the modified-retrospective transition method. A significant amount of the Company’s revenues are derived from net interest income on financial assets and liabilities, which are excluded from the scope of the amended guidance. Preliminary results indicate that certain noninterest income financial statement line items, including service charges on deposit accounts, trust and investment management income, and other noninterest income, contain revenue streams that are in scope of these updates. Based on the Company’s preliminary scoping, walkthroughs, and contract reviews, it does not expect to recognize a significant cumulative adjustment to equity upon implementation of the standard; however, the Company is still finalizing its reviews of contracts related to certain revenue streams. Further, the Company is still evaluating the standard’s guidance for assessment of gross versus net reporting of revenues and expenses related to certain arrangements such as card interchange fees and rewards programs. The Company does not expect a significant impact to the Company’s consolidated statements of comprehensive income or consolidated balance sheets from either a presentation or timing perspective, but the Company will be subject to expanded disclosure requirements. The Company is in the process of developing additional quantitative and qualitative disclosures that will be required upon adoption of the new revenue recognition standard. ASU No. 2016-01 In January 2016, the FASB issued ASU No. 2016-01, Financial Statements - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments will not change the guidance for classifying and measuring investments in debt securities or loans; however, the ASU will impact how the Company measures certain equity investments and discloses and presents certain financial instruments through the application of the “exit price” notion. ASU No. 2016-01 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. An entity will record a cumulative-effect adjustment to beginning retained earnings as of the beginning of the first reporting period in which the guidance is adopted, with two exceptions. The amendments related to equity investments without readily determinable fair values (including disclosure requirements) will be applied prospectively. The requirement to use the “exit price” notion to measure the fair value of financial instruments for disclosure purposes will also be applied prospectively. The Company does not expect a significant cumulative-effect adjustment to be recorded at adoption or any significant impact to the consolidated financial statements associated with the accounting for its current equity investments. The Company does anticipate financial statement disclosures to be impacted, specifically related to financial instruments measured at amortized cost whose fair values are disclosed under the “entry price” notion, but is currently still in the process of developing the appropriate methodology to measure fair value under the “exit price” notion and determining the impact. 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, with early adoption 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 will adopt the amendments on January 1, 2019. The Company occupies certain banking offices and equipment under operating lease agreements, which currently are not recognized in the consolidated balance sheets. Based on the Company’s preliminary analysis of its current portfolio, the impact to the Company’s consolidated balance sheets is estimated to result in less than a 1% increase in assets and liabilities. The Company is also currently assessing the practical expedients it may elect at adoption, the final determination of the incremental borrowing rate, and the impact to the regulatory capital ratios; amongst other matters associated with the standard. The adjustment to retained earnings is not expected to be significant based on the transition guidance associated with current sale-leaseback agreements. The Company also anticipates additional disclosures to be provided 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. 2017-04 In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment , which simplifies how an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Therefore, any carrying amount which exceeds the reporting unit’s fair value (up to the amount of goodwill recorded) will be recognized as an impairment loss. ASU No. 2017-04 will be effective for annual reporting periods beginning after December 15, 2019, including interim reporting periods within those periods. The amendments will be applied prospectively on or after the effective date. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. Based on recent goodwill impairments tests, which did not require the application of Step 2, the Company does not expect the adoption of this ASU to have an immediate impact.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2017
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: June 30, 2017 (Dollars in thousands) Amortized Gross Gross Estimated Securities available for sale: U.S. Government-sponsored enterprise obligations $ 161,544 $ 164 $ (317 ) $ 161,391 Obligations of state and political subdivisions 296,062 5,902 (1,694 ) 300,270 Mortgage-backed securities 3,464,253 6,597 (31,118 ) 3,439,732 Other securities 107,796 666 (556 ) 107,906 Total securities available for sale $ 4,029,655 $ 13,329 $ (33,685 ) $ 4,009,299 Securities held to maturity: Obligations of state and political subdivisions $ 61,342 $ 1,588 $ (57 ) $ 62,873 Mortgage-backed securities 23,175 51 (651 ) 22,575 Total securities held to maturity $ 84,517 $ 1,639 $ (708 ) $ 85,448 December 31, 2016 (Dollars in thousands) Amortized Gross Gross Estimated Securities available for sale: U.S. Government-sponsored enterprise obligations $ 212,662 $ 245 $ (549 ) $ 212,358 Obligations of state and political subdivisions 286,458 1,948 (5,207 ) 283,199 Mortgage-backed securities 2,888,180 4,820 (41,291 ) 2,851,709 Other securities 98,974 361 (504 ) 98,831 Total securities available for sale $ 3,486,274 $ 7,374 $ (47,551 ) $ 3,446,097 Securities held to maturity: Obligations of state and political subdivisions $ 64,726 $ 1,609 $ (133 ) $ 66,202 Mortgage-backed securities 24,490 57 (817 ) 23,730 Total securities held to maturity $ 89,216 $ 1,666 $ (950 ) $ 89,932 Securities with carrying values of $1.7 billion and $1.5 billion were pledged to secure public deposits and other borrowings at June 30, 2017 and December 31, 2016 , 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: June 30, 2017 Less Than Twelve Months Over Twelve Months Total (Dollars in thousands) Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Securities available for sale: U.S. Government-sponsored enterprise obligations $ (317 ) $ 110,276 $ — $ — $ (317 ) $ 110,276 Obligations of state and political subdivisions (1,580 ) 82,187 (114 ) 4,541 (1,694 ) 86,728 Mortgage-backed securities (27,763 ) 2,330,909 (3,355 ) 165,156 (31,118 ) 2,496,065 Other Securities (540 ) 38,666 (16 ) 1,417 (556 ) 40,083 Total securities available for sale $ (30,200 ) $ 2,562,038 $ (3,485 ) $ 171,114 $ (33,685 ) $ 2,733,152 Securities held to maturity: Obligations of state and political subdivisions $ (57 ) $ 5,014 $ — $ — $ (57 ) $ 5,014 Mortgage-backed securities (200 ) 11,844 (451 ) 10,308 (651 ) 22,152 Total securities held to maturity $ (257 ) $ 16,858 $ (451 ) $ 10,308 $ (708 ) $ 27,166 December 31, 2016 Less Than Twelve Months Over Twelve Months Total (Dollars in thousands) Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Securities available for sale: U.S. Government-sponsored enterprise obligations $ (549 ) $ 150,554 $ — $ — $ (549 ) $ 150,554 Obligations of state and political subdivisions (5,207 ) 148,059 — — (5,207 ) 148,059 Mortgage-backed securities (38,667 ) 2,191,563 (2,624 ) 98,912 (41,291 ) 2,290,475 Other Securities (451 ) 36,484 (53 ) 3,850 (504 ) 40,334 Total securities available for sale $ (44,874 ) $ 2,526,660 $ (2,677 ) $ 102,762 $ (47,551 ) $ 2,629,422 Securities held to maturity: Obligations of state and political subdivisions $ (133 ) $ 10,602 $ — $ — $ (133 ) $ 10,602 Mortgage-backed securities (330 ) 12,288 (487 ) 10,960 (817 ) 23,248 Total securities held to maturity $ (463 ) $ 22,890 $ (487 ) $ 10,960 $ (950 ) $ 33,850 The Company assessed the nature of the unrealized losses in its portfolio as of June 30, 2017 and December 31, 2016 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, including the issuer’s failures 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 June 30, 2017 or December 31, 2016 . At June 30, 2017 , 386 debt securities had unrealized losses of 1.23% of the securities’ amortized cost basis. At December 31, 2016 , 397 debt securities had unrealized losses of 1.79% 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 June 30, 2017 and December 31, 2016 is presented in the following table. (Dollars in thousands) June 30, 2017 December 31, 2016 Number of securities: Issued by U.S. Government-sponsored enterprises 43 28 Other 2 3 45 31 Amortized Cost Basis: Issued by U.S. Government-sponsored enterprises $ 183,926 $ 112,983 Other 1,432 3,903 $ 185,358 $ 116,886 Unrealized Loss: Issued by U.S. Government-sponsored enterprises $ 3,920 $ 3,111 Other 16 53 $ 3,936 $ 3,164 The U.S. Government-sponsored enterprises securities are rated AA+ by S&P and Aaa by Moodys. The amortized cost and estimated fair value of investment securities by maturity at June 30, 2017 are presented 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 (Dollars in thousands) Weighted Amortized Estimated Weighted Amortized Estimated Within one year or less 1.61 % $ 22,066 $ 22,008 2.65 % $ 1,622 $ 1,626 One through five years 1.78 250,400 250,806 2.75 10,234 10,378 After five through ten years 2.34 837,818 840,128 3.24 21,161 21,836 Over ten years 2.27 2,919,371 2,896,357 2.98 51,500 51,608 2.25 % $ 4,029,655 $ 4,009,299 3.01 % $ 84,517 $ 85,448 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 June 30 Six Months Ended June 30, (Dollars in thousands) 2017 2016 2017 2016 Realized gains $ 242 $ 2,473 $ 242 $ 2,935 Realized losses (183 ) (684 ) (183 ) (950 ) $ 59 $ 1,789 $ 59 $ 1,985 In addition to the gains above, the Company realized certain gains on calls of securities held to maturity that were not significant to the consolidated financial statements. Other Equity Securities The Company accounts for the following securities at amortized cost, which approximates fair value, in “other assets” on the consolidated balance sheets: (Dollars in thousands) June 30, 2017 December 31, 2016 Federal Home Loan Bank (FHLB) stock $ 38,539 $ 42,326 Federal Reserve Bank (FRB) stock 48,584 48,584 Other investments 3,008 2,808 $ 90,131 $ 93,718

Loans

Loans	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Loans	90 days Total Past Due Non-accrual Loans Total Loans Commercial real estate - construction $ 1,008,834 $ 214 $ — $ — $ 214 $ 1,431 $ 1,010,479 Commercial real estate - owner-occupied 1,804,289 343 1,687 33 2,063 8,815 1,815,167 Commercial real estate- non-owner-occupied 3,277,719 3,245 3,046 267 6,558 5,007 3,289,284 Commercial and industrial 3,349,442 10,633 1,429 — 12,062 29,195 3,390,699 Energy-related 453,357 2,240 — — 2,240 94,565 550,162 Residential mortgage 955,343 1,933 1,693 310 3,936 11,682 970,961 Consumer - home equity 1,819,163 4,983 4,161 — 9,144 10,534 1,838,841 Consumer - indirect automobile 89,590 1,353 261 — 1,614 902 92,106 Consumer - credit card 85,690 168 117 — 285 612 86,587 Consumer - other 444,743 2,809 567 — 3,376 1,005 449,124 Total $ 13,288,170 $ 27,921 $ 12,961 $ 610 $ 41,492 $ 163,748 $ 13,493,410 December 31, 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 $ 740,761 $ — $ — $ — $ — $ — $ 740,761 Commercial real estate - owner-occupied 1,775,695 959 127 — 1,086 7,843 1,784,624 Commercial real estate- non-owner-occupied 3,088,207 902 224 — 1,126 8,596 3,097,929 Commercial and industrial 3,158,700 3,999 870 — 4,869 31,227 3,194,796 Energy-related 407,434 — 1,526 — 1,526 150,329 559,289 Residential mortgage 836,509 2,012 1,577 1,104 4,693 13,014 854,216 Consumer - home equity 1,768,763 5,249 1,430 — 6,679 7,979 1,783,421 Consumer - indirect automobile 127,054 2,551 405 — 2,956 1,038 131,048 Consumer - credit card 81,602 199 99 — 298 624 82,524 Consumer - other 462,650 2,155 618 — 2,773 893 466,316 Total $ 12,447,375 $ 18,026 $ 6,876 $ 1,104 $ 26,006 $ 221,543 $ 12,694,924 June 30, 2017 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 53,564 $ 216 $ — $ — $ 216 $ 1,118 $ (183 ) $ 34,994 $ 89,709 Commercial real estate - owner-occupied 284,841 — — — — 3,684 (2,670 ) 104,386 390,241 Commercial real estate- non-owner-occupied 441,193 2,067 319 — 2,386 4,035 (94 ) 99,203 546,723 Commercial and industrial 256,584 47 4,651 — 4,698 1,382 (712 ) 31,430 293,382 Energy-related 1,657 154 — — 154 — (5 ) — 1,806 Residential mortgage 263,658 14 403 192 609 1,598 (1,609 ) 111,250 375,506 Consumer - home equity 242,091 407 1,279 — 1,686 1,947 (4,497 ) 78,880 320,107 Consumer - indirect automobile 18 — — — — — — 6 24 Consumer - credit card — — — — — — — 501 501 Consumer - other 40,644 307 94 — 401 444 (859 ) 3,977 44,607 Total $ 1,584,250 $ 3,212 $ 6,746 $ 192 $ 10,150 $ 14,208 $ (10,629 ) $ 464,627 $ 2,062,606 December 31, 2016 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 26,714 $ — $ — $ — $ — $ 1,946 $ (243 ) $ 32,991 $ 61,408 Commercial real estate - owner-occupied 326,761 493 55 — 548 166 (3,084 ) 125,621 450,012 Commercial real estate- non-owner-occupied 544,731 223 — 32 255 1,055 (565 ) 122,056 667,532 Commercial and industrial 314,990 73 51 — 124 1,317 (837 ) 32,732 348,326 Energy-related 1,910 — — — — — (6 ) — 1,904 Residential mortgage 290,031 328 989 — 1,317 719 (1,835 ) 122,952 413,184 Consumer - home equity 286,411 1,078 189 250 1,517 1,395 (5,237 ) 88,419 372,505 Consumer - indirect automobile — — — — — — — 4 4 Consumer - credit card 468 — — — — — — — 468 Consumer - other 49,449 391 97 — 488 360 (1,004 ) 5,411 54,704 Total $ 1,841,465 $ 2,586 $ 1,381 $ 282 $ 4,249 $ 6,958 $ (12,811 ) $ 530,186 $ 2,370,047 (1) Past due and non-accrual information presents acquired loans at the gross loan balance, prior to application of discounts. (2) Past due and non-accrual 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 The following is a summary of changes in the accretable difference for all loans accounted for under ASC 310-30 during the six months ended June 30: (Dollars in thousands) 2017 2016 Balance at beginning of period $ 175,054 $ 227,502 Transfers from non-accretable difference to accretable yield 2,544 4,425 Accretion (28,496 ) (36,256 ) Changes in expected cash flows not affecting non-accretable differences (1) 2,439 8,949 Balance at end of period $ 151,541 $ 204,620 (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 June 30, 2017 and 2016 is presented in the following tables. Modifications of loans that are accounted for within a pool under ASC Topic 310-30 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 such acquired loans that would otherwise meet the criteria for classification as a TDR are excluded from the tables below. TDRs totaling $28.4 million and $165.3 million occurred during the six months ended June 30, 2017 and June 30, 2016, respectively, through modification of the original loan terms. The following table provides information on how the TDRs were modified during the periods indicated: Three Months Ended June 30 Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Extended maturities $ 8,488 $ 54,758 $ 15,014 $ 57,533 Maturity and interest rate adjustment 3,886 30,781 6,502 31,048 Movement to or extension of interest-rate only payments 38 440 138 440 Interest rate adjustment 26 134 26 134 Forbearance 3,466 33,426 4,687 38,367 Other concession(s) (1) 1,988 15,985 2,031 37,761 Total $ 17,892 $ 135,524 $ 28,398 $ 165,283 (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 $28.4 million of TDRs occurring during the six months ended June 30, 2017, $22.8 million are on accrual status and $5.6 million are on non-accrual status. Of the $165.3 million of TDRs occurring during the six months ended June 30, 2016, $126.6 million were on accrual status and $38.7 million were on non-accrual status. The following table presents the end of period balance for loans modified in a TDR during the periods indicated: Three Months Ended June 30 2017 2016 (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- construction 1 $ 275 $ 275 — $ — $ — Commercial real estate- owner-occupied 1 32 31 3 794 785 Commercial real estate- non-owner-occupied 6 2,721 2,795 6 10,777 10,047 Commercial and industrial 24 9,028 8,551 16 19,496 19,353 Energy-related — — — 19 82,882 100,205 Residential mortgage 6 521 492 10 1,438 1,438 Consumer - home equity 33 4,820 4,807 36 2,750 2,750 Consumer - indirect 23 224 114 — — — Consumer - other 30 832 827 61 946 946 Total 124 $ 18,453 $ 17,892 151 $ 119,083 $ 135,524 Six Months Ended June 30 2017 2016 (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- construction 1 $ 275 $ 275 1 $ 28 $ 26 Commercial real estate- owner-occupied 2 1,730 1,698 5 1,069 1,050 Commercial real estate- non-owner-occupied 11 4,409 4,465 10 11,516 10,749 Commercial and industrial 33 9,254 8,747 28 24,018 23,632 Energy-related — — — 25 110,443 119,890 Residential mortgage 10 780 730 25 4,733 4,692 Consumer - home equity 66 10,851 10,771 57 3,928 3,916 Consumer - indirect 33 360 222 — — — Consumer - other 50 1,547 1,490 85 1,386 1,328 Total 206 $ 29,206 $ 28,398 236 $ 157,121 $ 165,283 Information detailing TDRs that defaulted during the three-month and six-month periods ended June 30, 2017 and 2016, and were modified in the previous twelve months (i.e., the twelve months prior to the default) is presented in the following tables. 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 respective periods, or since the date of modification, whichever is shorter. Three Months Ended June 30 2017 2016 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate- construction — $ — — $ — Commercial real estate- owner-occupied 5 2,297 — — Commercial real estate- non-owner-occupied 9 5,640 4 1,358 Commercial and industrial 17 8,081 5 758 Energy-related — — 1 2,250 Residential mortgage 5 454 4 480 Consumer - home equity 19 1,532 17 1,112 Consumer - indirect automobile 9 75 — — Consumer - other 17 592 34 482 Total 81 $ 18,671 65 $ 6,440 Six Months Ended June 30 2017 2016 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate- construction 2 $ 132 — $ — Commercial real estate- owner-occupied 7 2,404 — — Commercial real estate- non-owner-occupied 14 6,406 8 1,377 Commercial and industrial 25 8,239 8 3,273 Energy-related — — 1 2,250 Residential mortgage 21 1,854 7 536 Consumer - home equity 37 2,488 24 1,608 Consumer - indirect automobile 33 328 — — Consumer - other 29 893 67 598 Total 168 $ 22,744 115 $ 9,642" id="sjs-B4">LOANS Loans consist of the following, segregated into legacy and acquired loans, for the periods indicated: June 30, 2017 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Commercial real estate- construction $ 1,010,479 $ 89,709 $ 1,100,188 Commercial real estate- owner-occupied 1,815,167 390,241 2,205,408 Commercial real estate- non-owner-occupied 3,289,284 546,723 3,836,007 Commercial and industrial 3,390,699 293,382 3,684,081 Energy-related 550,162 1,806 551,968 10,055,791 1,321,861 11,377,652 Residential mortgage loans: 970,961 375,506 1,346,467 Consumer and other loans: Home equity 1,838,841 320,107 2,158,948 Indirect automobile 92,106 24 92,130 Other 535,711 45,108 580,819 2,466,658 365,239 2,831,897 Total $ 13,493,410 $ 2,062,606 $ 15,556,016 December 31, 2016 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Commercial real estate- construction $ 740,761 $ 61,408 $ 802,169 Commercial real estate- owner-occupied 1,784,624 450,012 2,234,636 Commercial real estate- non-owner-occupied 3,097,929 667,532 3,765,461 Commercial and industrial 3,194,796 348,326 3,543,122 Energy-related 559,289 1,904 561,193 9,377,399 1,529,182 10,906,581 Residential mortgage loans: 854,216 413,184 1,267,400 Consumer and other loans: Home equity 1,783,421 372,505 2,155,926 Indirect automobile 131,048 4 131,052 Other 548,840 55,172 604,012 2,463,309 427,681 2,890,990 Total $ 12,694,924 $ 2,370,047 $ 15,064,971 Net deferred loan origination fees were $24.1 million and $22.6 million at June 30, 2017 and December 31, 2016, 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 June 30, 2017 and December 31, 2016, overdrafts of $5.9 million and $4.2 million , respectively, have been reclassified to loans. Loans with carrying values of $4.5 billion were pledged as collateral for borrowings at both June 30, 2017 and December 31, 2016, respectively. Aging Analysis The following tables provide an analysis of the aging of loans as of June 30, 2017 and December 31, 2016. Due to the difference in accounting for acquired loans, the tables below further segregate the Company’s loans between loans originated, or renewed and underwritten by the Company ("legacy loans") and acquired loans. June 30, 2017 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 $ 1,008,834 $ 214 $ — $ — $ 214 $ 1,431 $ 1,010,479 Commercial real estate - owner-occupied 1,804,289 343 1,687 33 2,063 8,815 1,815,167 Commercial real estate- non-owner-occupied 3,277,719 3,245 3,046 267 6,558 5,007 3,289,284 Commercial and industrial 3,349,442 10,633 1,429 — 12,062 29,195 3,390,699 Energy-related 453,357 2,240 — — 2,240 94,565 550,162 Residential mortgage 955,343 1,933 1,693 310 3,936 11,682 970,961 Consumer - home equity 1,819,163 4,983 4,161 — 9,144 10,534 1,838,841 Consumer - indirect automobile 89,590 1,353 261 — 1,614 902 92,106 Consumer - credit card 85,690 168 117 — 285 612 86,587 Consumer - other 444,743 2,809 567 — 3,376 1,005 449,124 Total $ 13,288,170 $ 27,921 $ 12,961 $ 610 $ 41,492 $ 163,748 $ 13,493,410 December 31, 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 $ 740,761 $ — $ — $ — $ — $ — $ 740,761 Commercial real estate - owner-occupied 1,775,695 959 127 — 1,086 7,843 1,784,624 Commercial real estate- non-owner-occupied 3,088,207 902 224 — 1,126 8,596 3,097,929 Commercial and industrial 3,158,700 3,999 870 — 4,869 31,227 3,194,796 Energy-related 407,434 — 1,526 — 1,526 150,329 559,289 Residential mortgage 836,509 2,012 1,577 1,104 4,693 13,014 854,216 Consumer - home equity 1,768,763 5,249 1,430 — 6,679 7,979 1,783,421 Consumer - indirect automobile 127,054 2,551 405 — 2,956 1,038 131,048 Consumer - credit card 81,602 199 99 — 298 624 82,524 Consumer - other 462,650 2,155 618 — 2,773 893 466,316 Total $ 12,447,375 $ 18,026 $ 6,876 $ 1,104 $ 26,006 $ 221,543 $ 12,694,924 June 30, 2017 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 53,564 $ 216 $ — $ — $ 216 $ 1,118 $ (183 ) $ 34,994 $ 89,709 Commercial real estate - owner-occupied 284,841 — — — — 3,684 (2,670 ) 104,386 390,241 Commercial real estate- non-owner-occupied 441,193 2,067 319 — 2,386 4,035 (94 ) 99,203 546,723 Commercial and industrial 256,584 47 4,651 — 4,698 1,382 (712 ) 31,430 293,382 Energy-related 1,657 154 — — 154 — (5 ) — 1,806 Residential mortgage 263,658 14 403 192 609 1,598 (1,609 ) 111,250 375,506 Consumer - home equity 242,091 407 1,279 — 1,686 1,947 (4,497 ) 78,880 320,107 Consumer - indirect automobile 18 — — — — — — 6 24 Consumer - credit card — — — — — — — 501 501 Consumer - other 40,644 307 94 — 401 444 (859 ) 3,977 44,607 Total $ 1,584,250 $ 3,212 $ 6,746 $ 192 $ 10,150 $ 14,208 $ (10,629 ) $ 464,627 $ 2,062,606 December 31, 2016 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 26,714 $ — $ — $ — $ — $ 1,946 $ (243 ) $ 32,991 $ 61,408 Commercial real estate - owner-occupied 326,761 493 55 — 548 166 (3,084 ) 125,621 450,012 Commercial real estate- non-owner-occupied 544,731 223 — 32 255 1,055 (565 ) 122,056 667,532 Commercial and industrial 314,990 73 51 — 124 1,317 (837 ) 32,732 348,326 Energy-related 1,910 — — — — — (6 ) — 1,904 Residential mortgage 290,031 328 989 — 1,317 719 (1,835 ) 122,952 413,184 Consumer - home equity 286,411 1,078 189 250 1,517 1,395 (5,237 ) 88,419 372,505 Consumer - indirect automobile — — — — — — — 4 4 Consumer - credit card 468 — — — — — — — 468 Consumer - other 49,449 391 97 — 488 360 (1,004 ) 5,411 54,704 Total $ 1,841,465 $ 2,586 $ 1,381 $ 282 $ 4,249 $ 6,958 $ (12,811 ) $ 530,186 $ 2,370,047 (1) Past due and non-accrual information presents acquired loans at the gross loan balance, prior to application of discounts. (2) Past due and non-accrual 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 The following is a summary of changes in the accretable difference for all loans accounted for under ASC 310-30 during the six months ended June 30: (Dollars in thousands) 2017 2016 Balance at beginning of period $ 175,054 $ 227,502 Transfers from non-accretable difference to accretable yield 2,544 4,425 Accretion (28,496 ) (36,256 ) Changes in expected cash flows not affecting non-accretable differences (1) 2,439 8,949 Balance at end of period $ 151,541 $ 204,620 (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 June 30, 2017 and 2016 is presented in the following tables. Modifications of loans that are accounted for within a pool under ASC Topic 310-30 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 such acquired loans that would otherwise meet the criteria for classification as a TDR are excluded from the tables below. TDRs totaling $28.4 million and $165.3 million occurred during the six months ended June 30, 2017 and June 30, 2016, respectively, through modification of the original loan terms. The following table provides information on how the TDRs were modified during the periods indicated: Three Months Ended June 30 Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Extended maturities $ 8,488 $ 54,758 $ 15,014 $ 57,533 Maturity and interest rate adjustment 3,886 30,781 6,502 31,048 Movement to or extension of interest-rate only payments 38 440 138 440 Interest rate adjustment 26 134 26 134 Forbearance 3,466 33,426 4,687 38,367 Other concession(s) (1) 1,988 15,985 2,031 37,761 Total $ 17,892 $ 135,524 $ 28,398 $ 165,283 (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 $28.4 million of TDRs occurring during the six months ended June 30, 2017, $22.8 million are on accrual status and $5.6 million are on non-accrual status. Of the $165.3 million of TDRs occurring during the six months ended June 30, 2016, $126.6 million were on accrual status and $38.7 million were on non-accrual status. The following table presents the end of period balance for loans modified in a TDR during the periods indicated: Three Months Ended June 30 2017 2016 (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- construction 1 $ 275 $ 275 — $ — $ — Commercial real estate- owner-occupied 1 32 31 3 794 785 Commercial real estate- non-owner-occupied 6 2,721 2,795 6 10,777 10,047 Commercial and industrial 24 9,028 8,551 16 19,496 19,353 Energy-related — — — 19 82,882 100,205 Residential mortgage 6 521 492 10 1,438 1,438 Consumer - home equity 33 4,820 4,807 36 2,750 2,750 Consumer - indirect 23 224 114 — — — Consumer - other 30 832 827 61 946 946 Total 124 $ 18,453 $ 17,892 151 $ 119,083 $ 135,524 Six Months Ended June 30 2017 2016 (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- construction 1 $ 275 $ 275 1 $ 28 $ 26 Commercial real estate- owner-occupied 2 1,730 1,698 5 1,069 1,050 Commercial real estate- non-owner-occupied 11 4,409 4,465 10 11,516 10,749 Commercial and industrial 33 9,254 8,747 28 24,018 23,632 Energy-related — — — 25 110,443 119,890 Residential mortgage 10 780 730 25 4,733 4,692 Consumer - home equity 66 10,851 10,771 57 3,928 3,916 Consumer - indirect 33 360 222 — — — Consumer - other 50 1,547 1,490 85 1,386 1,328 Total 206 $ 29,206 $ 28,398 236 $ 157,121 $ 165,283 Information detailing TDRs that defaulted during the three-month and six-month periods ended June 30, 2017 and 2016, and were modified in the previous twelve months (i.e., the twelve months prior to the default) is presented in the following tables. 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 respective periods, or since the date of modification, whichever is shorter. Three Months Ended June 30 2017 2016 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate- construction — $ — — $ — Commercial real estate- owner-occupied 5 2,297 — — Commercial real estate- non-owner-occupied 9 5,640 4 1,358 Commercial and industrial 17 8,081 5 758 Energy-related — — 1 2,250 Residential mortgage 5 454 4 480 Consumer - home equity 19 1,532 17 1,112 Consumer - indirect automobile 9 75 — — Consumer - other 17 592 34 482 Total 81 $ 18,671 65 $ 6,440 Six Months Ended June 30 2017 2016 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate- construction 2 $ 132 — $ — Commercial real estate- owner-occupied 7 2,404 — — Commercial real estate- non-owner-occupied 14 6,406 8 1,377 Commercial and industrial 25 8,239 8 3,273 Energy-related — — 1 2,250 Residential mortgage 21 1,854 7 536 Consumer - home equity 37 2,488 24 1,608 Consumer - indirect automobile 33 328 — — Consumer - other 29 893 67 598 Total 168 $ 22,744 115 $ 9,642

Allowance for Credit Losses and

Allowance for Credit Losses and Credit Quality	6 Months Ended
	Jun. 30, 2017
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 six months ended June 30 is as follows: 2017 (Dollars in thousands) Legacy Loans Acquired Loans Total Allowance for credit losses Allowance for loan losses at beginning of period $ 105,569 $ 39,150 $ 144,719 Provision for (Reversal of) loan losses 18,315 (111 ) 18,204 Transfer of balance to OREO and other — 258 258 Loans charged-off (18,098 ) (1,382 ) (19,480 ) Recoveries 1,824 700 2,524 Allowance for loan losses at end of period $ 107,610 $ 38,615 $ 146,225 Reserve for unfunded commitments at beginning of period $ 11,241 $ — $ 11,241 Provision for (Reversal of) unfunded lending commitments (779 ) — (779 ) Reserve for unfunded commitments at end of period $ 10,462 $ — $ 10,462 Allowance for credit losses at end of period $ 118,072 $ 38,615 $ 156,687 2016 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 28,390 (2,416 ) 25,974 Adjustment attributable to FDIC loss share arrangements — 797 797 Net provision for (Reversal of) loan losses 28,390 (1,619 ) 26,771 Adjustment attributable to FDIC loss share arrangements — (797 ) (797 ) Transfer of balance to OREO and other — (967 ) (967 ) Loans charged-off (17,359 ) (1,196 ) (18,555 ) Recoveries 2,022 600 2,622 Allowance for loan losses at end of period $ 106,861 $ 40,591 $ 147,452 Reserve for unfunded commitments at beginning of period $ 14,145 $ — $ 14,145 Provision for (Reversal of) unfunded lending commitments (319 ) — (319 ) Reserve for unfunded commitments at end of period $ 13,826 $ — $ 13,826 Allowance for credit losses at end of period $ 120,687 $ 40,591 $ 161,278 A summary of changes in the allowance for credit losses for legacy loans, by loan portfolio type, for the six months ended June 30 is as follows: 2017 (Dollars in thousands) Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage Consumer Total Allowance for loan losses at beginning of period $ 25,408 $ 35,434 $ 22,486 $ 3,835 $ 18,406 $ 105,569 Provision for (Reversal of) loan losses 4,323 5,181 3,387 (884 ) 6,308 18,315 Loans charged-off (256 ) (8,366 ) (2,845 ) (45 ) (6,586 ) (18,098 ) Recoveries 189 269 — 77 1,289 1,824 Allowance for loan losses at end of period $ 29,664 $ 32,518 $ 23,028 $ 2,983 $ 19,417 $ 107,610 Reserve for unfunded commitments at beginning of period $ 3,206 $ 3,535 $ 1,003 $ 657 $ 2,840 $ 11,241 Provision for (Reversal of) unfunded commitments 294 (46 ) (856 ) (89 ) (82 ) (779 ) Reserve for unfunded commitments at end of period $ 3,500 $ 3,489 $ 147 $ 568 $ 2,758 $ 10,462 Allowance on loans individually evaluated for impairment $ 1,316 $ 7,192 $ 16,094 $ 137 $ 2,181 $ 26,920 Allowance on loans collectively evaluated for impairment 28,348 25,326 6,934 2,846 17,236 80,690 Loans, net of unearned income: Balance at end of period $ 6,114,930 $ 3,390,699 $ 550,162 $ 970,961 $ 2,466,658 $ 13,493,410 Balance at end of period individually evaluated for impairment 42,204 36,836 89,814 4,631 25,983 199,468 Balance at end of period collectively evaluated for impairment 6,072,726 3,353,863 460,348 966,330 2,440,675 13,293,942 2016 (Dollars in thousands) Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage 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 (715 ) 5,874 16,819 264 6,148 28,390 Loans charged-off (1,549 ) (1,154 ) (7,715 ) (173 ) (6,768 ) (17,359 ) Recoveries 644 35 — 27 1,316 2,022 Allowance for loan losses at end of period $ 23,038 $ 28,038 $ 32,967 $ 4,065 $ 18,753 $ 106,861 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 (26 ) (60 ) (442 ) (23 ) 232 (319 ) Reserve for unfunded commitments at end of period $ 4,134 $ 3,388 $ 2,223 $ 807 $ 3,274 $ 13,826 Allowance on loans individually evaluated for impairment $ 691 $ 969 $ 11,925 $ 100 $ 800 $ 14,485 Allowance on loans collectively evaluated for impairment 22,347 27,069 21,042 3,965 17,953 92,376 Loans, net of unearned income: Balance at end of period $ 5,097,689 $ 3,027,590 $ 659,510 $ 794,701 $ 2,405,359 $ 11,984,849 Balance at end of period individually evaluated for impairment 26,152 34,298 148,317 3,451 9,140 221,358 Balance at end of period collectively evaluated for impairment 5,071,537 2,993,292 511,193 791,250 2,396,219 11,763,491 A summary of changes in the allowance for loan losses for acquired loans, by loan portfolio type, for the six months ended June 30 is as follows: 2017 (Dollars in thousands) Commercial Commercial Energy-related Residential Consumer Total Allowance for loan losses at beginning of period $ 23,574 $ 3,230 $ 39 $ 7,412 $ 4,895 $ 39,150 Provision for (Reversal of) loan losses 1,407 (46 ) (21 ) (578 ) (873 ) (111 ) Transfer of balance to OREO and other 135 (69 ) — 2 190 258 Loans charged-off (1,026 ) (71 ) — (30 ) (255 ) (1,382 ) Recoveries 145 77 — 65 413 700 Allowance for loan losses at end of period $ 24,235 $ 3,121 $ 18 $ 6,871 $ 4,370 $ 38,615 Allowance on loans individually evaluated for impairment $ 402 $ 678 $ — $ 32 $ 92 $ 1,204 Allowance on loans collectively evaluated for impairment 23,833 2,443 18 6,839 4,278 37,411 Loans, net of unearned income: Balance at end of period $ 1,026,673 $ 293,382 $ 1,806 $ 375,506 $ 365,239 $ 2,062,606 Balance at end of period individually evaluated for impairment 10,225 2,851 — 660 2,856 16,592 Balance at end of period collectively evaluated for impairment 777,865 259,101 1,806 263,596 279,019 1,581,387 Balance at end of period acquired with deteriorated credit quality 238,583 31,430 — 111,250 83,364 464,627 2016 (Dollars in thousands) Commercial Commercial Energy-related Residential 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 (1,804 ) 350 (52 ) 896 (1,009 ) (1,619 ) Increase (Decrease) in FDIC loss share receivable 45 (28 ) — (562 ) (252 ) (797 ) Transfer of balance to OREO and other (880 ) 323 — 22 (432 ) (967 ) Loans charged-off (31 ) (700 ) — — (465 ) (1,196 ) Recoveries 85 112 — 29 374 600 Allowance for loan losses at end of period $ 23,394 $ 2,876 $ 73 $ 8,226 $ 6,022 $ 40,591 Allowance on loans individually evaluated for impairment $ — $ 22 $ — $ 2 $ 44 $ 68 Allowance on loans collectively evaluated for impairment 23,394 2,854 73 8,224 5,978 40,523 Loans, net of unearned income: Balance at end of period $ 1,374,312 $ 408,219 $ 2,524 $ 454,361 $ 498,296 $ 2,737,712 Balance at end of period individually evaluated for impairment 1,145 2,075 — 245 4,412 7,877 Balance at end of period collectively evaluated for impairment 1,038,737 368,283 2,524 321,879 386,080 2,117,503 Balance at end of period acquired with deteriorated credit quality 334,430 37,861 — 132,237 107,804 612,332 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, sales 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 non-conforming 1-4 family mortgage loans secured by properties located in the Company's market areas and originated under terms and documentation that permit their sale in a 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 which may result in future disclosure of these loans as non-performing. For problem assets with identified credit issues, the Company has two primary classifications: “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 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 higher based on currently existing facts, conditions, and values. 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, or renewed and underwritten by the Company (legacy loans) and acquired loans. Loan premiums/discounts in the tables below represent the adjustment of 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 June 30, 2017 and December 31, 2016. Credit quality information in the tables below includes total loans acquired (including acquired impaired loans) at the gross loan balance, prior to the application of premiums/discounts, at June 30, 2017 and December 31, 2016. Loan delinquency is the primary credit quality indicator that the Company utilizes to monitor consumer asset quality. Legacy loans June 30, 2017 December 31, 2016 (Dollars in thousands) Pass Special Mention Sub- Doubtful Total Pass Special Mention Sub- Doubtful Total Commercial real estate - construction $ 997,264 $ 7,917 $ 5,298 $ — $ 1,010,479 $ 734,687 $ 2,203 $ 3,871 $ — $ 740,761 Commercial real estate - owner-occupied 1,740,717 39,772 34,210 468 1,815,167 1,738,024 17,542 29,058 — 1,784,624 Commercial real estate- non-owner-occupied 3,251,368 8,696 29,220 — 3,289,284 3,063,470 8,617 25,842 — 3,097,929 Commercial and industrial 3,287,383 42,422 58,527 2,367 3,390,699 3,112,300 29,763 35,199 17,534 3,194,796 Energy-related 373,342 49,097 74,620 53,103 550,162 242,123 80,084 225,724 11,358 559,289 Total $ 9,650,074 $ 147,904 $ 201,875 $ 55,938 $ 10,055,791 $ 8,890,604 $ 138,209 $ 319,694 $ 28,892 $ 9,377,399 Legacy loans June 30, 2017 December 31, 2016 (Dollars in thousands) Current 30+ Days Past Due Total Current 30+ Days Past Due Total Residential mortgage $ 955,343 $ 15,618 $ 970,961 $ 836,509 $ 17,707 $ 854,216 Consumer - home equity 1,819,163 19,678 1,838,841 1,768,763 14,658 1,783,421 Consumer - indirect automobile 89,590 2,516 92,106 127,054 3,994 131,048 Consumer - credit card 85,690 897 86,587 81,602 922 82,524 Consumer - other 444,743 4,381 449,124 462,650 3,666 466,316 Total $ 3,394,529 $ 43,090 $ 3,437,619 $ 3,276,578 $ 40,947 $ 3,317,525 Acquired loans June 30, 2017 December 31, 2016 (Dollars in thousands) Pass Special Sub-standard Doubtful Premium/(Discount) Total Pass Special Sub-standard Doubtful Loss Premium/(Discount) Total Commercial real estate - construction $ 71,157 $ 1,208 $ 3,431 $ 14 $ 13,899 $ 89,709 $ 46,498 $ 459 $ 3,118 $ 2,574 $ — $ 8,759 $ 61,408 Commercial real estate - owner-occupied 384,411 3,275 14,627 — (12,072 ) 390,241 426,492 7,664 17,584 1,356 — (3,084 ) 450,012 Commercial real estate- non-owner-occupied 541,724 3,434 26,188 119 (24,742 ) 546,723 663,571 11,620 31,552 101 23 (39,335 ) 667,532 Commercial and industrial 275,350 5,440 11,315 2,601 (1,324 ) 293,382 323,154 1,416 27,749 494 — (4,487 ) 348,326 Energy-related 1,811 — — — (5 ) 1,806 1,910 — — — — (6 ) 1,904 Total $ 1,274,453 $ 13,357 $ 55,561 $ 2,734 $ (24,244 ) $ 1,321,861 $ 1,461,625 $ 21,159 $ 80,003 $ 4,525 $ 23 $ (38,153 ) $ 1,529,182 Acquired loans June 30, 2017 December 31, 2016 (Dollars in thousands) Current 30+ Days Past Due Premium (Discount) Total Current 30+ Days Past Due Premium (Discount) Total Residential mortgage $ 378,204 $ 22,121 $ (24,819 ) $ 375,506 $ 424,300 $ 20,914 $ (32,030 ) $ 413,184 Consumer - home equity 322,658 13,051 (15,602 ) 320,107 377,021 12,807 (17,323 ) 372,505 Consumer - indirect automobile 24 — — 24 12 — (8 ) 4 Consumer - other 48,168 1,225 (4,285 ) 45,108 58,141 1,423 (4,392 ) 55,172 Total $ 749,054 $ 36,397 $ (44,706 ) $ 740,745 $ 859,474 $ 35,144 $ (53,753 ) $ 840,865 Legacy Impaired Loans Information on the Company’s investment in legacy impaired loans, which include all TDRs and all other non-accrual loans evaluated or measured individually for impairment for purposes of determining the allowance for loan losses, is presented in the following tables as of and for the periods indicated. June 30, 2017 December 31, 2016 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- construction $ 2,123 $ 2,123 $ — $ 38 $ 38 $ — Commercial real estate- owner-occupied 13,932 13,932 — 4,593 4,593 — Commercial real estate- non-owner-occupied 4,443 4,443 — 12,668 11,876 — Commercial and industrial 16,016 16,016 — 14,202 13,189 — Energy-related 32,013 32,013 — 152,424 143,239 — Residential mortgage 1,123 1,123 — — — — Consumer - home equity 3,336 3,336 — — — — Consumer -other — — — — — — With an allowance recorded: Commercial real estate- construction 36 36 (1 ) — — — Commercial real estate- owner-occupied 17,945 17,945 (690 ) 17,580 17,429 (640 ) Commercial real estate- non-owner-occupied 3,725 3,725 (625 ) 108 95 (1 ) Commercial and industrial 20,820 20,820 (7,192 ) 28,829 28,329 (10,864 ) Energy-related 57,801 57,801 (16,094 ) 53,967 53,088 (9,769 ) Residential mortgage 3,543 3,508 (137 ) 4,627 4,312 (144 ) Consumer - home equity 18,865 18,757 (1,805 ) 13,906 13,257 (993 ) Consumer - indirect automobile 668 668 (83 ) 1,037 758 (114 ) Consumer - other 3,222 3,222 (293 ) 2,447 2,442 (251 ) Total $ 199,611 $ 199,468 $ (26,920 ) $ 306,426 $ 292,645 $ (22,776 ) Total commercial loans $ 168,854 $ 168,854 $ (24,602 ) $ 284,409 $ 271,876 $ (21,274 ) Total mortgage loans 4,666 4,631 (137 ) 4,627 4,312 (144 ) Total consumer loans 26,091 25,983 (2,181 ) 17,390 16,457 (1,358 ) Three Months Ended June 30, 2017 Three Months Ended June 30, 2016 Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 Average Interest Average Interest Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded: Commercial real estate- construction $ 2,123 $ 13 $ 27 $ — $ 2,123 $ 39 $ 30 $ — Commercial real estate- owner-occupied 14,054 158 2,072 20 14,179 404 2,085 41 Commercial real estate- non-owner-occupied 4,409 39 13,395 123 4,433 67 13,454 237 Commercial and industrial 21,116 106 36,212 467 21,998 232 41,074 947 Energy-related 32,370 44 106,692 912 34,330 102 102,364 1,857 Residential mortgage 1,130 12 825 10 1,136 24 825 19 Consumer - home equity 3,347 32 — — 3,356 65 — — With an allowance recorded: Commercial real estate- construction 37 1 — — 37 1 — — Commercial real estate- owner-occupied 17,908 86 10,636 83 17,998 186 10,694 166 Commercial real estate- non-owner-occupied 3,761 13 53 — 3,774 57 60 1 Commercial and industrial 21,028 284 2,125 23 21,504 555 2,191 48 Energy-related 58,399 2 15,486 10 58,868 4 12,290 47 Residential mortgage 3,528 34 2,642 18 3,549 68 2,657 38 Consumer - home equity 18,359 196 7,550 74 17,443 375 7,290 146 Consumer - indirect automobile 750 6 650 6 797 14 723 18 Consumer - other 3,100 51 846 15 2,921 96 702 25 Total $ 205,419 $ 1,077 $ 199,211 $ 1,761 $ 208,446 $ 2,289 $ 196,439 $ 3,590 Total commercial loans $ 175,205 $ 746 $ 186,698 $ 1,638 $ 179,244 $ 1,647 $ 184,242 $ 3,344 Total mortgage loans 4,658 46 3,467 28 4,685 92 3,482 57 Total consumer loans 25,556 285 9,046 95 24,517 550 8,715 189 As of June 30, 2017 and December 31, 2016, 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.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Jun. 30, 2017
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 six months ended June 30, 2017, and the year ended December 31, 2016 are provided in the following table. (Dollars in thousands) IBERIABANK IMC LTC Total Balance, December 31, 2015 $ 696,260 $ 23,178 $ 5,165 $ 724,603 Goodwill adjustments during the year 2,253 — — 2,253 Balance, December 31, 2016 $ 698,513 $ 23,178 $ 5,165 $ 726,856 Goodwill adjustments during the year — — — — Balance, June 30, 2017 $ 698,513 $ 23,178 $ 5,165 $ 726,856 The goodwill adjustments during 2016 were the result of the finalization of fair value estimates related to the 2015 acquisitions of Florida Bank Group, Old Florida, and Georgia Commerce during the respective measurement periods. The Company performed the required annual goodwill impairment test as of October 1, 2016. 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 a subsequent interim test was not necessary. 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: June 30, 2017 December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Mortgage servicing rights $ 8,265 $ (3,576 ) $ 4,689 $ 7,202 $ (3,144 ) $ 4,058 In addition, there was an insignificant amount of non-mortgage servicing rights related to SBA loans as of June 30, 2017 and December 31, 2016, respectively. 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 June 30, 2017 and December 31, 2016. No events or changes in circumstances occurred during the six months ended June 30, 2017 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: June 30, 2017 December 31, 2016 (Dollars in thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core deposit intangibles $ 74,001 $ (55,501 ) $ 18,500 $ 74,001 $ (52,165 ) $ 21,836 Customer relationship intangible asset 1,143 (942 ) 201 1,348 (1,064 ) 284 Non-compete agreement 63 (31 ) 32 63 (22 ) 41 Total $ 75,207 $ (56,474 ) $ 18,733 $ 75,412 $ (53,251 ) $ 22,161

Derivative Instruments and Othe

Derivative Instruments and Other Hedging Activities	6 Months Ended
	Jun. 30, 2017
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, written and purchased options and credit derivatives. 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: Balance Sheet Location Derivative Assets - Fair Value Balance Sheet Location Derivative Liabilities - Fair Value (Dollars in thousands) June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ — $ — Other liabilities $ 1,041 $ 525 Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ — $ 1,041 $ 525 Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ 20,432 $ 20,719 Other liabilities $ 18,384 $ 20,719 Foreign exchange contracts Other assets 73 27 Other liabilities 73 26 Forward sales contracts Other assets 860 6,014 Other liabilities 706 794 Written and purchased options Other assets 11,535 12,125 Other liabilities 8,439 8,098 Other contracts Other assets — 1 Other liabilities 41 47 Total derivatives not designated as hedging instruments under ASC Topic 815 $ 32,900 $ 38,886 $ 27,643 $ 29,684 Total $ 32,900 $ 38,886 $ 28,684 $ 30,209 Derivative Assets - Notional Amount Derivative Liabilities - Notional Amount (Dollars in thousands) June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 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 $ 1,120,278 $ 1,033,955 $ 1,120,278 $ 1,033,955 Foreign exchange contracts 1,724 4,474 1,724 4,474 Forward sales contracts 214,925 229,181 131,915 120,567 Written and purchased options 369,582 289,115 177,921 154,170 Other contracts 8,630 8,784 103,055 106,518 Total derivatives not designated as hedging instruments under ASC Topic 815 $ 1,715,139 $ 1,565,509 $ 1,534,893 $ 1,419,684 Total $ 1,715,139 $ 1,565,509 $ 1,643,393 $ 1,528,184 The Company has entered into risk participation agreements with counterparties to transfer or assume credit exposures related to interest rate derivatives. The notional amounts of risk participation agreements sold were $103.1 million and $106.5 million at June 30, 2017 and December 31, 2016, respectively. Assuming all underlying third party customers referenced in the swap contracts defaulted at June 30, 2017 and December 31, 2016, the exposure from these agreements would not be material based on the fair value of the underlying swaps. 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 June 30, 2017 and December 31, 2016, the Company was required to post $1.5 million and $1.9 million , respectively, in cash or securities as collateral for its derivative transactions, which is included in "interest-bearing deposits in banks" on the Company’s consolidated balance sheets. Effective January 3, 2017, the Chicago Mercantile Exchange and LCH.Clearnet Limited amended their rulebooks to legally characterize variation margin payments for over-the-counter derivatives they clear as settlements of the derivatives' exposure rather than collateral against the exposures. As of June 30, 2017 , the Company was required to post $2.7 million in variation margin payments for its derivative transactions, which is now required to be netted against the fair value of the derivatives in "other assets/other liabilities" on the consolidated balance sheet. 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 June 30, 2017. 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. June 30, 2017 Gross Amounts Presented in the Balance Sheet Gross Amounts Not Offset in the Balance Sheet Net (Dollars in thousands) Derivatives Collateral (1) Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 20,432 $ (8,747 ) $ — $ 11,685 Written and purchased options 8,329 — — 8,329 Total derivative assets subject to master netting arrangements $ 28,761 $ (8,747 ) $ — $ 20,014 Derivative liabilities Interest rate contracts designated as hedging instruments $ 1,041 $ — $ — $ 1,041 Interest rate contracts not designated as hedging instruments 18,384 (8,747 ) (1,513 ) 8,124 Total derivative liabilities subject to master netting arrangements $ 19,425 $ (8,747 ) $ (1,513 ) $ 9,165 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities . December 31, 2016 Gross Amounts Presented in the Balance Sheet Gross Amounts Not Offset in the Balance Sheet Net (Dollars in thousands) Derivatives Collateral (1) Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 20,719 $ (9,677 ) $ — $ 11,042 Written and purchased options 8,085 — — 8,085 Total derivative assets subject to master netting arrangements $ 28,804 $ (9,677 ) $ — $ 19,127 Derivative liabilities Interest rate contracts designated as hedging instruments $ 525 $ — $ (181 ) $ 344 Interest rate contracts not designated as hedging instruments 20,719 (9,677 ) (1,711 ) 9,331 Total derivative liabilities subject to master netting arrangements $ 21,244 $ (9,677 ) $ (1,892 ) $ 9,675 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities. During the six months ended June 30, 2017 and 2016 , 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 June 30, 2017 , the Company does not expect to reclassify a material amount from accumulated other comprehensive income into interest income over the next twelve months for derivatives that will be settled. At June 30, 2017 and 2016 , and for the three and six 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 net of taxes (Effective Portion) (Dollars in thousands) For the Three Months Ended June 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2017 2016 2017 2016 2017 2016 Interest rate contracts $ (790 ) $ (2,328 ) Other income (expense) $ (103 ) $ — Other income (expense) $ — $ — Total $ (790 ) $ (2,328 ) $ (103 ) $ — $ — $ — 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 net of taxes (Effective Portion) (Dollars in thousands) For the Six Months Ended June 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2017 2016 2017 2016 2017 2016 Interest rate contracts $ (627 ) $ (6,455 ) Other income (expense) $ (148 ) $ — Other income (expense) $ — $ — Total $ (627 ) $ (6,455 ) $ (148 ) $ — $ — $ — At June 30, 2017 and 2016, and for the three and six months then ended, information pertaining to the effect of derivatives not designated as hedging instruments on the consolidated financial statements is as follows: Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives For the Three Months Ended June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Interest rate contracts (1) Other income $ 1,299 $ 2,332 $ 2,416 $ 5,294 Foreign exchange contracts Other income 7 2 14 3 Forward sales contracts Mortgage income (1,526 ) (4,787 ) (1,886 ) (10,130 ) Written and purchased options Mortgage income (1,586 ) 2,488 (931 ) 6,470 Other contracts Other income 5 — 9 — Total $ (1,801 ) $ 35 $ (378 ) $ 1,637 (1) Includes fees associated with customer interest rate contracts.

Shareholders' Equity, Capital R

Shareholders' Equity, Capital Ratios and Other Regulatory Matters	6 Months Ended
	Jun. 30, 2017
Banking and Thrift [Abstract]
Shareholders' Equity, Capital Ratios and Other Regulatory Matters	SHAREHOLDERS' EQUITY, CAPITAL RATIOS AND OTHER REGULATORY MATTERS Preferred Stock The following table presents a summary of the Company's non-cumulative perpetual preferred stock: June 30, 2017 December 31, 2016 Issuance Date Earliest Redemption Date Annual Dividend Rate Liquidation Amount Carrying Amount Carrying Amount (Dollars in thousands) Series B Preferred Stock 8/5/2015 8/1/2025 6.625 % $ 80,000 $ 76,812 $ 76,812 Series C Preferred Stock 5/9/2016 5/1/2026 6.600 % 57,500 55,285 55,285 $ 137,500 $ 132,097 $ 132,097 Common Stock During the second quarter of 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 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. At June 30, 2017, the remaining common shares that could be repurchased under the plan approved by the Board was 747,494 shares. The Company has not repurchased any common shares during 2017. On March 7, 2017, the Company issued an additional 6,100,000 shares of its common stock at a price of $83.00 per common share. Net proceeds from the offering, after deduction of underwriting discounts, commissions, and direct issuance costs, were $485.2 million . Regulatory Capital The Company and IBERIABANK are subject to various regulatory capital requirements administered by the federal and state banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s consolidated financial statements. Under capital adequacy regulations 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. Management believes that, as of June 30, 2017, the Company and IBERIABANK met all capital adequacy requirements to which they are subject. As of June 30, 2017, the most recent notification from the FRB categorized IBERIABANK as well-capitalized under the regulatory framework for prompt corrective action (the prompt corrective action requirements are not applicable to the Company). 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 June 30, 2017 and December 31, 2016 are presented in the following table. (Dollars in thousands) June 30, 2017 Minimum Well-Capitalized Actual Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 845,167 4.00 % N/A N/A $ 2,787,729 13.19 % IBERIABANK 842,313 4.00 1,052,892 5.00 1,994,073 9.47 Common Equity Tier 1 (CET1) (1) Consolidated $ 822,980 4.50 % N/A N/A $ 2,655,632 14.52 % IBERIABANK 820,978 4.50 1,185,857 6.50 1,994,073 10.93 Tier 1 Risk-Based Capital (1) Consolidated $ 1,097,306 6.00 % N/A N/A $ 2,787,729 15.24 % IBERIABANK 1,094,637 6.00 1,459,516 8.00 1,994,073 10.93 Total Risk-Based Capital (1) Consolidated $ 1,463,075 8.00 % N/A N/A $ 3,060,916 16.74 % IBERIABANK 1,459,516 8.00 1,824,395 10.00 2,150,760 11.79 December 31, 2016 Minimum Well-Capitalized Actual Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 818,440 4.00 % N/A N/A $ 2,221,528 10.86 % IBERIABANK 816,152 4.00 1,020,190 5.00 1,878,703 9.21 Common Equity Tier 1 (CET1) (1) Consolidated $ 794,334 4.50 % N/A N/A $ 2,089,431 11.84 % IBERIABANK 792,111 4.50 1,144,160 6.50 1,878,703 10.67 Tier 1 Risk-Based Capital (1) Consolidated $ 1,059,112 6.00 % N/A N/A $ 2,221,528 12.59 % IBERIABANK 1,056,147 6.00 1,408,197 8.00 1,878,703 10.67 Total Risk-Based Capital (1) Consolidated $ 1,412,149 8.00 % N/A N/A $ 2,493,988 14.13 % IBERIABANK 1,408,197 8.00 1,760,246 10.00 2,034,663 11.56 (1) Minimum capital ratios are subject to a capital conservation buffer. In order to avoid limitations on distributions, including dividend payments, and certain discretionary bonus payments to executive officers, an institution must hold a capital conservation buffer above its minimum risk-based capital requirements. This capital conservation buffer is calculated as the lowest of the differences between the actual CET1 ratio, Tier 1 Risk-Based Capital Ratio, and Total Risk-Based Capital ratio and the corresponding minimum ratios.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2017
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 June 30, Six Months Ended June 30, (In thousands, except per share data) 2017 2016 2017 2016 Earnings per common share - basic: Net income $ 52,018 $ 50,810 $ 102,491 $ 93,579 Preferred stock dividends (949 ) (854 ) (4,548 ) (3,430 ) Dividends and undistributed earnings allocated to unvested restricted shares (361 ) (540 ) (707 ) (1,003 ) Net income allocated to common shareholders - basic $ 50,708 $ 49,416 $ 97,236 $ 89,146 Weighted average common shares outstanding 50,630 40,771 48,389 40,741 Earnings per common share - basic 1.00 1.21 2.01 2.19 Earnings per common share - diluted: Net income allocated to common shareholders - basic $ 50,708 $ 49,416 $ 97,236 $ 89,146 Dividends and undistributed earnings allocated to unvested restricted shares (2 ) (12 ) (39 ) (13 ) Net income allocated to common shareholders - diluted $ 50,706 $ 49,404 $ 97,197 $ 89,133 Weighted average common shares outstanding 50,630 40,771 48,389 40,741 Dilutive potential common shares 354 137 362 86 Weighted average common shares outstanding - diluted 50,984 40,908 48,751 40,827 Earnings per common share - diluted $ 0.99 $ 1.21 $ 1.99 $ 2.18 For the three months ended June 30, 2017 , and 2016 , the calculations for basic shares outstanding exclude the weighted average shares owned by the Recognition and Retention Plan (“RRP”) of 365,087 and 461,124 , respectively. For the six months ended June 30, 2017, and 2016, basic shares outstanding exclude 385,876 and 468,273 shares owned by the RRP, respectively. The effects from the assumed exercises of 69,289 and 262,853 stock options were not included in the computation of diluted earnings per share for the three months ended June 30, 2017 and 2016 , respectively, because such amounts would have had an antidilutive effect on earnings per common share. For the six months ended June 30, 2017, and 2016, the effects from the assumed exercise of 69,289 and 482,272 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	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017, awards of 2,081,303 shares could be made under approved incentive compensation plans. The Company issues shares to fulfill stock option exercises and restricted share units and restricted stock awards vesting from available authorized common shares. At June 30, 2017, the Company believes there are adequate authorized shares to satisfy anticipated stock option exercises and restricted share unit and restricted stock award vesting. 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 149,932 47.46 Exercised (8,811 ) 55.62 Forfeited or expired (45,723 ) 60.97 Outstanding options, June 30, 2016 909,175 $ 55.23 Exercisable options, June 30, 2016 598,469 $ 56.31 Outstanding options, December 31, 2016 721,538 $ 55.38 Granted 71,491 85.42 Exercised (64,163 ) 55.05 Forfeited or expired (15,091 ) 74.72 Outstanding options, June 30, 2017 713,775 $ 58.01 Exercisable options, June 30, 2017 470,841 $ 55.79 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 Six Months Ended June 30 2017 2016 Expected dividends 1.7 % 2.9 % Expected volatility 24.9 % 29.1 % Risk-free interest rate 2.1 % 1.4 % Expected term (in years) 5.6 6.5 Weighted-average grant-date fair value $ 18.76 $ 10.10 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 and related income tax benefits in the accompanying consolidated statements of comprehensive income related to stock options for the following periods: For the Three Months Ended June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Compensation expense related to stock options $ 344 $ 502 $ 789 $ 987 Income tax benefit related to stock options 47 81 115 162 At June 30, 2017, 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 2.8 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 (generally three to seven years). As of June 30, 2017 and 2016, unrecognized share-based compensation associated with these awards totaled $20.0 million and $21.1 million , respectively. The unrecognized compensation cost related to restricted stock awards at June 30, 2017 is expected to be recognized over a weighted-average period of 1.6 years . Restricted share units During the first six months of 2017 and 2016, 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 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 and related income tax benefits 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 June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Compensation expense related to restricted stock awards and restricted share units $ 3,045 $ 3,329 $ 6,322 $ 6,715 Income tax benefit related to restricted stock awards and restricted share units 1,066 1,165 2,213 2,350 The following table represents unvested restricted stock award and restricted share unit activity for the following periods: For the Six Months Ended June 30 2017 2016 Balance at beginning of period 543,258 507,130 Granted 163,353 240,699 Forfeited (9,951 ) (9,040 ) Earned and issued (185,092 ) (172,356 ) Balance at end of period 511,568 566,433 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 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 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. There were no performance units granted in 2017 or 2016. The following table indicates compensation expense recorded for phantom stock and performance units based on the number of share equivalents vested at June 30 of the years indicated and the current market price of the Company’s stock at that time: For the Three Months Ended June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Compensation expense related to phantom stock and performance units $ 2,889 $ 2,793 $ 5,942 $ 5,198 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 192,359 11,490 Forfeited share equivalents (16,283 ) 973 Vested share equivalents (147,511 ) 7,452 Balance, June 30, 2016 490,995 $ 29,327 Balance, December 31, 2016 472,830 $ 39,600 Granted 105,048 8,561 Forfeited share equivalents (15,104 ) 1,231 Vested share equivalents (150,409 ) 14,246 Balance, June 30, 2017 412,365 $ 33,608 (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 $81.50 and $59.73 on June 30, 2017, and 2016, respectively.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
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 Annual Report on Form 10-K for the year ended December 31, 2016, for a description of how fair value measurements are determined. June 30, 2017 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 4,009,299 $ — $ 4,009,299 Mortgage loans held for sale — 140,959 — 140,959 Derivative instruments — 32,900 — 32,900 Total $ — $ 4,183,158 $ — $ 4,183,158 Liabilities Derivative instruments $ — $ 28,684 $ — $ 28,684 Total $ — $ 28,684 $ — $ 28,684 December 31, 2016 Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 3,446,097 $ — $ 3,446,097 Mortgage loans held for sale — 157,041 — 157,041 Derivative instruments — 38,886 — 38,886 Total $ — $ 3,642,024 $ — $ 3,642,024 Liabilities Derivative instruments $ — $ 30,209 $ — $ 30,209 Total $ — $ 30,209 $ — $ 30,209 During the six months ended June 30, 2017 , 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. June 30, 2017 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 97,363 $ 97,363 OREO, net — — 2,871 2,871 Total $ — $ — $ 100,234 $ 100,234 December 31, 2016 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 93,485 $ 93,485 OREO, net — — 185 185 Total $ — $ — $ 93,670 $ 93,670 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. 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 June 30, 2017 and December 31, 2016 . Fair value option The Company has elected the fair value option for certain originated residential mortgage loans held for sale, which allows for a more effective offset of the changes in fair values of the loans and the derivative instruments used to hedge them without the burden of complying with the requirements for hedge accounting. The Company has $13.3 million and $12.7 million of mortgage loans held for investment for which the fair value option was elected upon origination and continue to be accounted for at fair value at June 30, 2017 and December 31, 2016, respectively. 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 six months ended June 30, 2017 totaled $343.3 thousand and $(65.4) thousand , respectively. These loans were transferred from loans held for sale to loans held for investment during the third quarter of 2016. 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: June 30, 2017 December 31, 2016 (Dollars in thousands) Aggregate Fair Value Aggregate Unpaid Principal Aggregate Fair Value Less Unpaid Principal Aggregate Fair Value Aggregate Unpaid Principal Aggregate Fair Value Less Unpaid Principal Mortgage loans held for sale, at fair value $ 140,959 $ 137,524 $ 3,435 $ 157,041 $ 153,801 $ 3,240 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 six months ended June 30, 2017 totaled $32.1 thousand and $871.0 thousand , respectively, while net gains resulting from the change in fair value of these loans were $2.0 million and $3.9 million for the three and six months ended June 30, 2016, respectively. The changes in fair value are mostly offset by economic hedging activities, with an insignificant portion of these changes attributable to changes in instrument-specific credit risk.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2017
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 2016 Annual Report on Form 10-K for the year ended December 31, 2016 for a description of how fair value measurements are determined. June 30, 2017 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 469,360 $ 469,360 $ 469,360 $ — $ — Investment securities 4,093,816 4,094,747 — 4,094,747 — Loans and loans held for sale, net of unearned income and allowance for loan losses 15,550,750 15,667,569 — 140,959 15,526,610 Derivative instruments 32,900 32,900 — 32,900 — Financial Liabilities Deposits $ 16,853,116 $ 15,817,343 $ — $ — $ 15,817,343 Short-term borrowings 583,935 583,935 333,935 250,000 — Long-term debt 667,243 658,483 — — 658,483 Derivative instruments 28,684 28,684 — 28,684 — December 31, 2016 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 1,362,126 $ 1,362,126 $ 1,362,126 $ — $ — Investment securities 3,535,313 3,536,029 — 3,536,029 — Loans and loans held for sale, net of unearned income and allowance for loan losses 15,077,293 15,066,055 — 157,041 14,909,014 Derivative instruments 38,886 38,886 — 38,886 — Financial Liabilities Deposits $ 17,408,283 $ 16,762,475 $ — $ — $ 16,762,475 Short-term borrowings 509,136 509,136 334,136 175,000 — Long-term debt 628,953 617,656 — — 617,656 Derivative instruments 30,209 30,209 — 30,209 — The fair value estimates presented herein are based upon pertinent information available to management as of June 30, 2017 and December 31, 2016 . Although management is not aware of any factors that would significantly affect the estimated fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since that date and, therefore, current estimates of fair value may differ significantly from the amounts presented herein.

Business Segments

Business Segments	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 202,694 $ 1,881 $ — $ 204,575 Interest expense 20,932 — — 20,932 Net interest income 181,762 1,881 — 183,643 Provision for/(reversal of) loan losses 12,134 (84 ) — 12,050 Mortgage income — 19,730 — 19,730 Service charges on deposit accounts 11,410 — — 11,410 Title revenue — — 6,190 6,190 Other non-interest income 18,647 (11 ) — 18,636 Allocated expenses (3,322 ) 2,490 832 — Non-interest expense 120,698 22,417 4,393 147,508 Income/(loss) before income tax expense 82,309 (3,223 ) 965 80,051 Income tax expense/(benefit) 28,745 (1,094 ) 382 28,033 Net income/(loss) $ 53,564 $ (2,129 ) $ 583 $ 52,018 Total loans and loans held for sale, net of unearned income $ 15,504,171 $ 192,804 $ — $ 15,696,975 Total assets 21,549,557 215,862 25,308 21,790,727 Total deposits 16,852,620 496 — 16,853,116 Average assets 21,593,026 226,326 24,185 21,843,537 Three Months Ended June 30, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 176,564 $ 2,130 $ — $ 178,694 Interest expense 14,782 1,159 — 15,941 Net interest income 161,782 971 — 162,753 Provision for loan losses 11,866 — — 11,866 Mortgage income 7 25,984 — 25,991 Service charges on deposit accounts 10,940 — — 10,940 Title revenue — — 6,135 6,135 Other non-interest income 21,843 8 — 21,851 Allocated expenses (3,885 ) 2,947 938 — Non-interest expense 120,268 14,820 4,416 139,504 Income/(loss) before income tax expense 66,323 9,196 781 76,300 Income tax expense/(benefit) 21,558 3,625 307 25,490 Net income/(loss) $ 44,765 $ 5,571 $ 474 $ 50,810 Total loans and loans held for sale, net of unearned income $ 14,702,843 $ 249,371 $ — $ 14,952,214 Total assets 19,807,507 326,397 26,951 20,160,855 Total deposits 15,855,908 6,119 — 15,862,027 Average assets 19,668,456 308,647 26,814 20,003,917 Six Months Ended June 30, 2017 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 393,517 $ 3,590 $ 1 $ 397,108 Interest expense 40,647 — — 40,647 Net interest income 352,870 3,590 1 356,461 Provision for/(reversal of) loan losses 18,292 (88 ) — 18,204 Mortgage income — 33,845 — 33,845 Service charges on deposit accounts 22,563 — — 22,563 Title revenue — — 10,931 10,931 Other non-interest income 36,000 (21 ) (6 ) 35,973 Allocated expenses (5,496 ) 4,146 1,350 — Non-interest expense 242,349 37,584 8,593 288,526 Income/(loss) before income tax expense 156,288 (4,228 ) 983 153,043 Income tax expense/(benefit) 51,574 (1,416 ) 394 50,552 Net income/(loss) $ 104,714 $ (2,812 ) $ 589 $ 102,491 Total loans and loans held for sale, net of unearned income $ 15,504,171 $ 192,804 $ — $ 15,696,975 Total assets 21,549,557 215,862 25,308 21,790,727 Total deposits 16,852,620 496 — 16,853,116 Average assets 21,572,094 256,343 24,032 21,852,469 Six Months Ended June 30, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 351,888 $ 3,741 $ 1 $ 355,630 Interest expense 29,436 2,038 — 31,474 Net interest income 322,452 1,703 1 324,156 Provision for loan losses 26,771 — — 26,771 Mortgage income 6 45,925 — 45,931 Service charges on deposit accounts 21,891 — — 21,891 Title revenue — — 10,880 10,880 Other non-interest income 42,053 7 — 42,060 Allocated expenses (6,554 ) 4,997 1,557 — Non-interest expense 240,295 28,018 8,643 276,956 Income/(loss) before income tax expense 125,890 14,620 681 141,191 Income tax expense/(benefit) 41,559 5,778 275 47,612 Net income/(loss) $ 84,331 $ 8,842 $ 406 $ 93,579 Total loans and loans held for sale, net of unearned income $ 14,702,843 $ 249,371 $ — $ 14,952,214 Total assets 19,807,507 326,397 26,951 20,160,855 Total deposits 15,855,908 6,119 — 15,862,027 Average assets 19,525,087 280,464 27,063 19,832,614

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017 and December 31, 2016, the fair value of guarantees under commercial and standby letters of credit was $1.8 million and $1.6 million , respectively. This fair value will decrease as the existing commercial and standby letters of credit approach their expiration dates. At June 30, 2017 and December 31, 2016, respectively, the Company had the following financial instruments outstanding and related reserves, whose contract amounts represent credit risk: (Dollars in thousands) June 30, 2017 December 31, 2016 Commitments to grant loans $ 518,934 $ 355,558 Unfunded commitments under lines of credit 5,051,175 4,899,930 Commercial and standby letters of credit 183,031 163,560 Reserve for unfunded lending commitments 10,462 11,241 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 5 for additional information 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. 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, the Company 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 Company's FHA-related policies and practices. After the Company complied with the subpoena, attorneys from the Department of Justice (“DOJ”) informed the Company in late March of 2017 that a civil qui tam suit had been filed against the Company in federal court involving the subject matter of the HUD subpoena (collectively, “the mortgage lawsuit”). The complaint was under partial seal by the district court judge, but the judge has now removed the seal order and thus the lawsuit is public. However, the Company has not been formally served with process. The Company began preliminary discussions with representatives from the DOJ regarding the mortgage lawsuit in mid-April of 2017 and began early-stage settlement discussions in late May that have continued through the date of this filing. Based on the developments late in the second quarter of 2017, the Company concluded that a loss is reasonably possible, the range of which is between $6 million and $17 million . As of the date of this filing, the Company is unable to conclude on an amount of probable loss within this range, and accordingly, IBERIABANK recorded a $6 million accrual during the second quarter. IBERIABANK has insurance policies and will pursue coverage under those policies. 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 and available insurance coverage, the Company’s management believes that it has established appropriate legal reserves. Any liabilities arising from pending legal proceedings are not expected to have a material adverse effect on the Company’s consolidated financial position, consolidated results of operations, or consolidated cash flows other than the HUD matter disclosed above. However, it is possible that the ultimate resolution of these matters, if unfavorable, may be material to the Company’s consolidated financial position, consolidated results of operations, or consolidated cash flows. As of the date of this filing, the Company believes the amount of losses associated with legal proceedings that it is reasonably possible to incur above amounts already accrued is not material, other than the HUD matter discussed above.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2017
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 not material to the consolidated financial statements at June 30, 2017 and December 31, 2016. None of the related party loans were classified as non-accrual, past due, troubled debt restructurings, or potential problem loans at June 30, 2017 and December 31, 2016, with the exception of the loan discussed below. IBERIABANK and several other financial institutions previously extended credit (the “Credit Facility”) under a multi-bank syndicated credit facility to Stone Energy Corporation (the “Borrower"). At the time of origination and subsequent restructure, one of the Company’s directors, David H. Welch, was the Chairman, President and Chief Executive Officer of the Borrower. IBERIABANK held approximately 6 percent of the total commitments from twelve banks under the Credit Facility. On December 14, 2016, the Borrower filed for Chapter 11 Bankruptcy with the U.S. Bankruptcy Court in the Southern District of Texas. On February 28, 2017, the Borrower’s confirmed Amended Joint Prepackaged Plan of Reorganization became effective, and the Borrower satisfied the entire amount due and owing to the financial institutions, which was the principal amount outstanding under the Credit Facility at the time of the bankruptcy filing. On that date, the Borrower emerged from the Chapter 11 bankruptcy and entered into a new Exit Facility with the lenders, including IBERIABANK. The new Exit Facility, which replaced the Credit Facility, provides for a $200 million reserve-based credit facility with a maturity date of February 21, 2021. Interest on advances under the Exit Facility is calculated using the London Interbank Offering Rate ("LIBOR") or the base rate, at the election of the Borrower, plus, in each case an applicable margin. IBERIABANK holds a 5.9 percent pro-rata share, or $11.8 million , of the $200 million total committed under the new Exit Facility. At June 30, 2017, there were no draws or outstanding amounts under the Exit Facility. Effective April 28, 2017, David H. Welch retired as Chairman, President and Chief Executive Officer of the Borrower. Deposits from related parties held by the Company were not material at June 30, 2017 and December 31, 2016.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS On July 31, 2017, the Company completed its acquisition of Sabadell United Bank, N.A. ("Sabadell United") from Banco de Sabadell, S.A. ("Banco Sabadell"). Under the terms of the Stock Purchase Agreement, Banco Sabadell received $796 million in cash and approximately 2.6 million shares of the Company's common stock for total consideration of approximately $1.0 billion based on the Company's closing stock price on July 31, 2017. The cash consideration was financed through two public common stock offerings completed on December 7, 2016, and March 7, 2017. In connection with the closing of the acquisition, the Company entered into a Registration Rights Agreement, dated as of July 31, 2017, pursuant to which the Company has agreed to provide Banco Sabadell with certain customary registration rights with respect to the shares of IBKC common stock issued as consideration for the acquisition. The Registration Rights Agreement contains customary terms and conditions, including certain customary indemnification obligations. The registration obligations will terminate upon the earliest of six months after the completion of the acquisition, the sale of all registrable shares pursuant to an effective registration statement or the sale or transfer of all registrable shares to any person who is not an affiliate of Banco Sabadell. At June 30, 2017, Sabadell United had total assets of $5.7 billion , gross loans of $4.1 billion , and total deposits of $4.4 billion . Upon completion of the acquisition, the Company had approximately $28 billion in total assets. The branch and operating systems conversions associated with the acquisition are expected to be completed in October 2017. Due to the timing of the Sabadell United acquisition, the Company is continuing its evaluation of the fair value adjustments necessary to adjust the acquired assets and assumed liabilities to estimated fair value, as well as the related intangible assets associated with the transaction. The acquired assets and assumed liabilities, fair value adjustments, and required supplemental pro forma information will be disclosed in subsequent filings.

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Reclassification	Reclassifications Certain amounts reported in prior periods have been reclassified to conform to the current period presentation. These reclassifications did not have a material effect on previously reported consolidated financial statements.
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 $94 million and $91 million at June 30, 2017 and December 31, 2016, 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. Effective January 1, 2017, IBERIABANK Mortgage Company, previously a subsidiary of IBERIABANK, merged into IBERIABANK. 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 eight states through IBERIABANK. The Company also operates mortgage production offices in 10 states 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. 840 Denning, LLC invests in a commercial rental property. CDE is engaged in the purchase of tax credits.
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, and income taxes.
Concentration of Credit Risks	Concentrations of Credit Risk Most of the Company’s business activity is with customers located in the southeastern United States. 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 higher net worth clients. Repayments on loans are expected to come from cash flows of the borrower and/or guarantor. Losses on secured loans are limited by the net realizable value of the collateral upon default of the borrowers and guarantor support. Concentrations in commercial real estate have increased as a result of the Company's organic growth and recent acquisitions of banks with significant CRE portfolios. Additionally, as the Company has executed its risk-off strategy over the past two years, CRE concentrations have naturally increased as a percentage of the total portfolio. The Company believes it does not have any excessive concentrations to any one industry or customer.
Recent Accounting Pronouncements	Pronouncements adopted during the six months ended June 30, 2017: ASU No. 2016-09 The Company adopted the amendments of ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, effective January 1, 2017 as follows: (i) prospective adoption of the recognition of excess tax benefits associated with awards which vested or settled during the six months ended June 30, 2017 in the statement of comprehensive income; (ii) prospective adoption of the exclusion of excess tax benefits from assumed proceeds for the calculation of diluted EPS for the six months ended June 30, 2017; (iii) modified retrospective adoption of the minimum statutory withholdings requirements; (iv) modified retrospective adoption of the accounting policy election to account for forfeitures as they occur; and (v) prospective adoption of the classifications of certain cash flows associated with stock compensation. The adoption of these amendments did not, either individually or in aggregate, have a significant impact to the consolidated financial statements. ASU No. 2017-01 In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business , which introduces amendments that are intended to clarify the definition of a business to assist companies and other reporting organizations in evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments will be applied prospectively and are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those periods, with early adoption permitted. The Company early-adopted the amendments effective January 1, 2017. The adoption of this ASU did not and is not expected to have a significant impact on the Company’s consolidated financial statements. Pronouncements issued but not yet adopted: ASU No. 2014-09 In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers , which implements a common revenue standard and clarifies the principles used for recognizing revenue. The amendments in the ASU clarify that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in ASU No. 2014-09 will be effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. The amendments will be applied through the election of one of two retrospective methods. The Company will adopt the amendments beginning January 1, 2018 through the modified-retrospective transition method. A significant amount of the Company’s revenues are derived from net interest income on financial assets and liabilities, which are excluded from the scope of the amended guidance. Preliminary results indicate that certain noninterest income financial statement line items, including service charges on deposit accounts, trust and investment management income, and other noninterest income, contain revenue streams that are in scope of these updates. Based on the Company’s preliminary scoping, walkthroughs, and contract reviews, it does not expect to recognize a significant cumulative adjustment to equity upon implementation of the standard; however, the Company is still finalizing its reviews of contracts related to certain revenue streams. Further, the Company is still evaluating the standard’s guidance for assessment of gross versus net reporting of revenues and expenses related to certain arrangements such as card interchange fees and rewards programs. The Company does not expect a significant impact to the Company’s consolidated statements of comprehensive income or consolidated balance sheets from either a presentation or timing perspective, but the Company will be subject to expanded disclosure requirements. The Company is in the process of developing additional quantitative and qualitative disclosures that will be required upon adoption of the new revenue recognition standard. ASU No. 2016-01 In January 2016, the FASB issued ASU No. 2016-01, Financial Statements - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments will not change the guidance for classifying and measuring investments in debt securities or loans; however, the ASU will impact how the Company measures certain equity investments and discloses and presents certain financial instruments through the application of the “exit price” notion. ASU No. 2016-01 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. An entity will record a cumulative-effect adjustment to beginning retained earnings as of the beginning of the first reporting period in which the guidance is adopted, with two exceptions. The amendments related to equity investments without readily determinable fair values (including disclosure requirements) will be applied prospectively. The requirement to use the “exit price” notion to measure the fair value of financial instruments for disclosure purposes will also be applied prospectively. The Company does not expect a significant cumulative-effect adjustment to be recorded at adoption or any significant impact to the consolidated financial statements associated with the accounting for its current equity investments. The Company does anticipate financial statement disclosures to be impacted, specifically related to financial instruments measured at amortized cost whose fair values are disclosed under the “entry price” notion, but is currently still in the process of developing the appropriate methodology to measure fair value under the “exit price” notion and determining the impact. 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, with early adoption 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 will adopt the amendments on January 1, 2019. The Company occupies certain banking offices and equipment under operating lease agreements, which currently are not recognized in the consolidated balance sheets. Based on the Company’s preliminary analysis of its current portfolio, the impact to the Company’s consolidated balance sheets is estimated to result in less than a 1% increase in assets and liabilities. The Company is also currently assessing the practical expedients it may elect at adoption, the final determination of the incremental borrowing rate, and the impact to the regulatory capital ratios; amongst other matters associated with the standard. The adjustment to retained earnings is not expected to be significant based on the transition guidance associated with current sale-leaseback agreements. The Company also anticipates additional disclosures to be provided 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. 2017-04 In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment , which simplifies how an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Therefore, any carrying amount which exceeds the reporting unit’s fair value (up to the amount of goodwill recorded) will be recognized as an impairment loss. ASU No. 2017-04 will be effective for annual reporting periods beginning after December 15, 2019, including interim reporting periods within those periods. The amendments will be applied prospectively on or after the effective date. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. Based on recent goodwill impairments tests, which did not require the application of Step 2, the Company does not expect the adoption of this ASU to have an immediate impact.

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2017
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: June 30, 2017 (Dollars in thousands) Amortized Gross Gross Estimated Securities available for sale: U.S. Government-sponsored enterprise obligations $ 161,544 $ 164 $ (317 ) $ 161,391 Obligations of state and political subdivisions 296,062 5,902 (1,694 ) 300,270 Mortgage-backed securities 3,464,253 6,597 (31,118 ) 3,439,732 Other securities 107,796 666 (556 ) 107,906 Total securities available for sale $ 4,029,655 $ 13,329 $ (33,685 ) $ 4,009,299 Securities held to maturity: Obligations of state and political subdivisions $ 61,342 $ 1,588 $ (57 ) $ 62,873 Mortgage-backed securities 23,175 51 (651 ) 22,575 Total securities held to maturity $ 84,517 $ 1,639 $ (708 ) $ 85,448 December 31, 2016 (Dollars in thousands) Amortized Gross Gross Estimated Securities available for sale: U.S. Government-sponsored enterprise obligations $ 212,662 $ 245 $ (549 ) $ 212,358 Obligations of state and political subdivisions 286,458 1,948 (5,207 ) 283,199 Mortgage-backed securities 2,888,180 4,820 (41,291 ) 2,851,709 Other securities 98,974 361 (504 ) 98,831 Total securities available for sale $ 3,486,274 $ 7,374 $ (47,551 ) $ 3,446,097 Securities held to maturity: Obligations of state and political subdivisions $ 64,726 $ 1,609 $ (133 ) $ 66,202 Mortgage-backed securities 24,490 57 (817 ) 23,730 Total securities held to maturity $ 89,216 $ 1,666 $ (950 ) $ 89,932 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: June 30, 2017 Less Than Twelve Months Over Twelve Months Total (Dollars in thousands) Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Securities available for sale: U.S. Government-sponsored enterprise obligations $ (317 ) $ 110,276 $ — $ — $ (317 ) $ 110,276 Obligations of state and political subdivisions (1,580 ) 82,187 (114 ) 4,541 (1,694 ) 86,728 Mortgage-backed securities (27,763 ) 2,330,909 (3,355 ) 165,156 (31,118 ) 2,496,065 Other Securities (540 ) 38,666 (16 ) 1,417 (556 ) 40,083 Total securities available for sale $ (30,200 ) $ 2,562,038 $ (3,485 ) $ 171,114 $ (33,685 ) $ 2,733,152 Securities held to maturity: Obligations of state and political subdivisions $ (57 ) $ 5,014 $ — $ — $ (57 ) $ 5,014 Mortgage-backed securities (200 ) 11,844 (451 ) 10,308 (651 ) 22,152 Total securities held to maturity $ (257 ) $ 16,858 $ (451 ) $ 10,308 $ (708 ) $ 27,166 December 31, 2016 Less Than Twelve Months Over Twelve Months Total (Dollars in thousands) Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Securities available for sale: U.S. Government-sponsored enterprise obligations $ (549 ) $ 150,554 $ — $ — $ (549 ) $ 150,554 Obligations of state and political subdivisions (5,207 ) 148,059 — — (5,207 ) 148,059 Mortgage-backed securities (38,667 ) 2,191,563 (2,624 ) 98,912 (41,291 ) 2,290,475 Other Securities (451 ) 36,484 (53 ) 3,850 (504 ) 40,334 Total securities available for sale $ (44,874 ) $ 2,526,660 $ (2,677 ) $ 102,762 $ (47,551 ) $ 2,629,422 Securities held to maturity: Obligations of state and political subdivisions $ (133 ) $ 10,602 $ — $ — $ (133 ) $ 10,602 Mortgage-backed securities (330 ) 12,288 (487 ) 10,960 (817 ) 23,248 Total securities held to maturity $ (463 ) $ 22,890 $ (487 ) $ 10,960 $ (950 ) $ 33,850
Held-to-maturity Securities	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: June 30, 2017 Less Than Twelve Months Over Twelve Months Total (Dollars in thousands) Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Securities available for sale: U.S. Government-sponsored enterprise obligations $ (317 ) $ 110,276 $ — $ — $ (317 ) $ 110,276 Obligations of state and political subdivisions (1,580 ) 82,187 (114 ) 4,541 (1,694 ) 86,728 Mortgage-backed securities (27,763 ) 2,330,909 (3,355 ) 165,156 (31,118 ) 2,496,065 Other Securities (540 ) 38,666 (16 ) 1,417 (556 ) 40,083 Total securities available for sale $ (30,200 ) $ 2,562,038 $ (3,485 ) $ 171,114 $ (33,685 ) $ 2,733,152 Securities held to maturity: Obligations of state and political subdivisions $ (57 ) $ 5,014 $ — $ — $ (57 ) $ 5,014 Mortgage-backed securities (200 ) 11,844 (451 ) 10,308 (651 ) 22,152 Total securities held to maturity $ (257 ) $ 16,858 $ (451 ) $ 10,308 $ (708 ) $ 27,166 December 31, 2016 Less Than Twelve Months Over Twelve Months Total (Dollars in thousands) Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Securities available for sale: U.S. Government-sponsored enterprise obligations $ (549 ) $ 150,554 $ — $ — $ (549 ) $ 150,554 Obligations of state and political subdivisions (5,207 ) 148,059 — — (5,207 ) 148,059 Mortgage-backed securities (38,667 ) 2,191,563 (2,624 ) 98,912 (41,291 ) 2,290,475 Other Securities (451 ) 36,484 (53 ) 3,850 (504 ) 40,334 Total securities available for sale $ (44,874 ) $ 2,526,660 $ (2,677 ) $ 102,762 $ (47,551 ) $ 2,629,422 Securities held to maturity: Obligations of state and political subdivisions $ (133 ) $ 10,602 $ — $ — $ (133 ) $ 10,602 Mortgage-backed securities (330 ) 12,288 (487 ) 10,960 (817 ) 23,248 Total securities held to maturity $ (463 ) $ 22,890 $ (487 ) $ 10,960 $ (950 ) $ 33,850 The amortized cost and fair values of investment securities, with gross unrealized gains and losses, consist of the following: June 30, 2017 (Dollars in thousands) Amortized Gross Gross Estimated Securities available for sale: U.S. Government-sponsored enterprise obligations $ 161,544 $ 164 $ (317 ) $ 161,391 Obligations of state and political subdivisions 296,062 5,902 (1,694 ) 300,270 Mortgage-backed securities 3,464,253 6,597 (31,118 ) 3,439,732 Other securities 107,796 666 (556 ) 107,906 Total securities available for sale $ 4,029,655 $ 13,329 $ (33,685 ) $ 4,009,299 Securities held to maturity: Obligations of state and political subdivisions $ 61,342 $ 1,588 $ (57 ) $ 62,873 Mortgage-backed securities 23,175 51 (651 ) 22,575 Total securities held to maturity $ 84,517 $ 1,639 $ (708 ) $ 85,448 December 31, 2016 (Dollars in thousands) Amortized Gross Gross Estimated Securities available for sale: U.S. Government-sponsored enterprise obligations $ 212,662 $ 245 $ (549 ) $ 212,358 Obligations of state and political subdivisions 286,458 1,948 (5,207 ) 283,199 Mortgage-backed securities 2,888,180 4,820 (41,291 ) 2,851,709 Other securities 98,974 361 (504 ) 98,831 Total securities available for sale $ 3,486,274 $ 7,374 $ (47,551 ) $ 3,446,097 Securities held to maturity: Obligations of state and political subdivisions $ 64,726 $ 1,609 $ (133 ) $ 66,202 Mortgage-backed securities 24,490 57 (817 ) 23,730 Total securities held to maturity $ 89,216 $ 1,666 $ (950 ) $ 89,932
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 June 30, 2017 and December 31, 2016 is presented in the following table. (Dollars in thousands) June 30, 2017 December 31, 2016 Number of securities: Issued by U.S. Government-sponsored enterprises 43 28 Other 2 3 45 31 Amortized Cost Basis: Issued by U.S. Government-sponsored enterprises $ 183,926 $ 112,983 Other 1,432 3,903 $ 185,358 $ 116,886 Unrealized Loss: Issued by U.S. Government-sponsored enterprises $ 3,920 $ 3,111 Other 16 53 $ 3,936 $ 3,164
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 June 30, 2017 are presented 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 (Dollars in thousands) Weighted Amortized Estimated Weighted Amortized Estimated Within one year or less 1.61 % $ 22,066 $ 22,008 2.65 % $ 1,622 $ 1,626 One through five years 1.78 250,400 250,806 2.75 10,234 10,378 After five through ten years 2.34 837,818 840,128 3.24 21,161 21,836 Over ten years 2.27 2,919,371 2,896,357 2.98 51,500 51,608 2.25 % $ 4,029,655 $ 4,009,299 3.01 % $ 84,517 $ 85,448
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 June 30 Six Months Ended June 30, (Dollars in thousands) 2017 2016 2017 2016 Realized gains $ 242 $ 2,473 $ 242 $ 2,935 Realized losses (183 ) (684 ) (183 ) (950 ) $ 59 $ 1,789 $ 59 $ 1,985
Schedule of Securities in Other Assets on Company's Consolidated Balance Sheets	The Company accounts for the following securities at amortized cost, which approximates fair value, in “other assets” on the consolidated balance sheets: (Dollars in thousands) June 30, 2017 December 31, 2016 Federal Home Loan Bank (FHLB) stock $ 38,539 $ 42,326 Federal Reserve Bank (FRB) stock 48,584 48,584 Other investments 3,008 2,808 $ 90,131 $ 93,718

Loans (Tables)

Loans (Tables)	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Schedule of Non-Covered and Covered Loans	Loans consist of the following, segregated into legacy and acquired loans, for the periods indicated: June 30, 2017 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Commercial real estate- construction $ 1,010,479 $ 89,709 $ 1,100,188 Commercial real estate- owner-occupied 1,815,167 390,241 2,205,408 Commercial real estate- non-owner-occupied 3,289,284 546,723 3,836,007 Commercial and industrial 3,390,699 293,382 3,684,081 Energy-related 550,162 1,806 551,968 10,055,791 1,321,861 11,377,652 Residential mortgage loans: 970,961 375,506 1,346,467 Consumer and other loans: Home equity 1,838,841 320,107 2,158,948 Indirect automobile 92,106 24 92,130 Other 535,711 45,108 580,819 2,466,658 365,239 2,831,897 Total $ 13,493,410 $ 2,062,606 $ 15,556,016 December 31, 2016 (Dollars in thousands) Legacy Loans Acquired Loans Total Commercial loans: Commercial real estate- construction $ 740,761 $ 61,408 $ 802,169 Commercial real estate- owner-occupied 1,784,624 450,012 2,234,636 Commercial real estate- non-owner-occupied 3,097,929 667,532 3,765,461 Commercial and industrial 3,194,796 348,326 3,543,122 Energy-related 559,289 1,904 561,193 9,377,399 1,529,182 10,906,581 Residential mortgage loans: 854,216 413,184 1,267,400 Consumer and other loans: Home equity 1,783,421 372,505 2,155,926 Indirect automobile 131,048 4 131,052 Other 548,840 55,172 604,012 2,463,309 427,681 2,890,990 Total $ 12,694,924 $ 2,370,047 $ 15,064,971
Schedule of Aging of Loans	90 days Total Past Due Non-accrual Loans Total Loans Commercial real estate - construction $ 1,008,834 $ 214 $ — $ — $ 214 $ 1,431 $ 1,010,479 Commercial real estate - owner-occupied 1,804,289 343 1,687 33 2,063 8,815 1,815,167 Commercial real estate- non-owner-occupied 3,277,719 3,245 3,046 267 6,558 5,007 3,289,284 Commercial and industrial 3,349,442 10,633 1,429 — 12,062 29,195 3,390,699 Energy-related 453,357 2,240 — — 2,240 94,565 550,162 Residential mortgage 955,343 1,933 1,693 310 3,936 11,682 970,961 Consumer - home equity 1,819,163 4,983 4,161 — 9,144 10,534 1,838,841 Consumer - indirect automobile 89,590 1,353 261 — 1,614 902 92,106 Consumer - credit card 85,690 168 117 — 285 612 86,587 Consumer - other 444,743 2,809 567 — 3,376 1,005 449,124 Total $ 13,288,170 $ 27,921 $ 12,961 $ 610 $ 41,492 $ 163,748 $ 13,493,410 December 31, 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 $ 740,761 $ — $ — $ — $ — $ — $ 740,761 Commercial real estate - owner-occupied 1,775,695 959 127 — 1,086 7,843 1,784,624 Commercial real estate- non-owner-occupied 3,088,207 902 224 — 1,126 8,596 3,097,929 Commercial and industrial 3,158,700 3,999 870 — 4,869 31,227 3,194,796 Energy-related 407,434 — 1,526 — 1,526 150,329 559,289 Residential mortgage 836,509 2,012 1,577 1,104 4,693 13,014 854,216 Consumer - home equity 1,768,763 5,249 1,430 — 6,679 7,979 1,783,421 Consumer - indirect automobile 127,054 2,551 405 — 2,956 1,038 131,048 Consumer - credit card 81,602 199 99 — 298 624 82,524 Consumer - other 462,650 2,155 618 — 2,773 893 466,316 Total $ 12,447,375 $ 18,026 $ 6,876 $ 1,104 $ 26,006 $ 221,543 $ 12,694,924 June 30, 2017 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 53,564 $ 216 $ — $ — $ 216 $ 1,118 $ (183 ) $ 34,994 $ 89,709 Commercial real estate - owner-occupied 284,841 — — — — 3,684 (2,670 ) 104,386 390,241 Commercial real estate- non-owner-occupied 441,193 2,067 319 — 2,386 4,035 (94 ) 99,203 546,723 Commercial and industrial 256,584 47 4,651 — 4,698 1,382 (712 ) 31,430 293,382 Energy-related 1,657 154 — — 154 — (5 ) — 1,806 Residential mortgage 263,658 14 403 192 609 1,598 (1,609 ) 111,250 375,506 Consumer - home equity 242,091 407 1,279 — 1,686 1,947 (4,497 ) 78,880 320,107 Consumer - indirect automobile 18 — — — — — — 6 24 Consumer - credit card — — — — — — — 501 501 Consumer - other 40,644 307 94 — 401 444 (859 ) 3,977 44,607 Total $ 1,584,250 $ 3,212 $ 6,746 $ 192 $ 10,150 $ 14,208 $ (10,629 ) $ 464,627 $ 2,062,606 December 31, 2016 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 26,714 $ — $ — $ — $ — $ 1,946 $ (243 ) $ 32,991 $ 61,408 Commercial real estate - owner-occupied 326,761 493 55 — 548 166 (3,084 ) 125,621 450,012 Commercial real estate- non-owner-occupied 544,731 223 — 32 255 1,055 (565 ) 122,056 667,532 Commercial and industrial 314,990 73 51 — 124 1,317 (837 ) 32,732 348,326 Energy-related 1,910 — — — — — (6 ) — 1,904 Residential mortgage 290,031 328 989 — 1,317 719 (1,835 ) 122,952 413,184 Consumer - home equity 286,411 1,078 189 250 1,517 1,395 (5,237 ) 88,419 372,505 Consumer - indirect automobile — — — — — — — 4 4 Consumer - credit card 468 — — — — — — — 468 Consumer - other 49,449 391 97 — 488 360 (1,004 ) 5,411 54,704 Total $ 1,841,465 $ 2,586 $ 1,381 $ 282 $ 4,249 $ 6,958 $ (12,811 ) $ 530,186 $ 2,370,047 (1) Past due and non-accrual information presents acquired loans at the gross loan balance, prior to application of discounts. (2) Past due and non-accrual 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." id="sjs-B5">The following tables provide an analysis of the aging of loans as of June 30, 2017 and December 31, 2016. Due to the difference in accounting for acquired loans, the tables below further segregate the Company’s loans between loans originated, or renewed and underwritten by the Company ("legacy loans") and acquired loans. June 30, 2017 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 $ 1,008,834 $ 214 $ — $ — $ 214 $ 1,431 $ 1,010,479 Commercial real estate - owner-occupied 1,804,289 343 1,687 33 2,063 8,815 1,815,167 Commercial real estate- non-owner-occupied 3,277,719 3,245 3,046 267 6,558 5,007 3,289,284 Commercial and industrial 3,349,442 10,633 1,429 — 12,062 29,195 3,390,699 Energy-related 453,357 2,240 — — 2,240 94,565 550,162 Residential mortgage 955,343 1,933 1,693 310 3,936 11,682 970,961 Consumer - home equity 1,819,163 4,983 4,161 — 9,144 10,534 1,838,841 Consumer - indirect automobile 89,590 1,353 261 — 1,614 902 92,106 Consumer - credit card 85,690 168 117 — 285 612 86,587 Consumer - other 444,743 2,809 567 — 3,376 1,005 449,124 Total $ 13,288,170 $ 27,921 $ 12,961 $ 610 $ 41,492 $ 163,748 $ 13,493,410 December 31, 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 $ 740,761 $ — $ — $ — $ — $ — $ 740,761 Commercial real estate - owner-occupied 1,775,695 959 127 — 1,086 7,843 1,784,624 Commercial real estate- non-owner-occupied 3,088,207 902 224 — 1,126 8,596 3,097,929 Commercial and industrial 3,158,700 3,999 870 — 4,869 31,227 3,194,796 Energy-related 407,434 — 1,526 — 1,526 150,329 559,289 Residential mortgage 836,509 2,012 1,577 1,104 4,693 13,014 854,216 Consumer - home equity 1,768,763 5,249 1,430 — 6,679 7,979 1,783,421 Consumer - indirect automobile 127,054 2,551 405 — 2,956 1,038 131,048 Consumer - credit card 81,602 199 99 — 298 624 82,524 Consumer - other 462,650 2,155 618 — 2,773 893 466,316 Total $ 12,447,375 $ 18,026 $ 6,876 $ 1,104 $ 26,006 $ 221,543 $ 12,694,924 June 30, 2017 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 53,564 $ 216 $ — $ — $ 216 $ 1,118 $ (183 ) $ 34,994 $ 89,709 Commercial real estate - owner-occupied 284,841 — — — — 3,684 (2,670 ) 104,386 390,241 Commercial real estate- non-owner-occupied 441,193 2,067 319 — 2,386 4,035 (94 ) 99,203 546,723 Commercial and industrial 256,584 47 4,651 — 4,698 1,382 (712 ) 31,430 293,382 Energy-related 1,657 154 — — 154 — (5 ) — 1,806 Residential mortgage 263,658 14 403 192 609 1,598 (1,609 ) 111,250 375,506 Consumer - home equity 242,091 407 1,279 — 1,686 1,947 (4,497 ) 78,880 320,107 Consumer - indirect automobile 18 — — — — — — 6 24 Consumer - credit card — — — — — — — 501 501 Consumer - other 40,644 307 94 — 401 444 (859 ) 3,977 44,607 Total $ 1,584,250 $ 3,212 $ 6,746 $ 192 $ 10,150 $ 14,208 $ (10,629 ) $ 464,627 $ 2,062,606 December 31, 2016 Acquired loans (1) (2) 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 Discount/Premium Acquired Impaired Loans Total Loans Commercial real estate - construction $ 26,714 $ — $ — $ — $ — $ 1,946 $ (243 ) $ 32,991 $ 61,408 Commercial real estate - owner-occupied 326,761 493 55 — 548 166 (3,084 ) 125,621 450,012 Commercial real estate- non-owner-occupied 544,731 223 — 32 255 1,055 (565 ) 122,056 667,532 Commercial and industrial 314,990 73 51 — 124 1,317 (837 ) 32,732 348,326 Energy-related 1,910 — — — — — (6 ) — 1,904 Residential mortgage 290,031 328 989 — 1,317 719 (1,835 ) 122,952 413,184 Consumer - home equity 286,411 1,078 189 250 1,517 1,395 (5,237 ) 88,419 372,505 Consumer - indirect automobile — — — — — — — 4 4 Consumer - credit card 468 — — — — — — — 468 Consumer - other 49,449 391 97 — 488 360 (1,004 ) 5,411 54,704 Total $ 1,841,465 $ 2,586 $ 1,381 $ 282 $ 4,249 $ 6,958 $ (12,811 ) $ 530,186 $ 2,370,047 (1) Past due and non-accrual information presents acquired loans at the gross loan balance, prior to application of discounts. (2) Past due and non-accrual 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.
Summary of Changes in Accretable Yields of Acquired Loans	The following is a summary of changes in the accretable difference for all loans accounted for under ASC 310-30 during the six months ended June 30: (Dollars in thousands) 2017 2016 Balance at beginning of period $ 175,054 $ 227,502 Transfers from non-accretable difference to accretable yield 2,544 4,425 Accretion (28,496 ) (36,256 ) Changes in expected cash flows not affecting non-accretable differences (1) 2,439 8,949 Balance at end of period $ 151,541 $ 204,620 (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 periods indicated: Three Months Ended June 30 Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Extended maturities $ 8,488 $ 54,758 $ 15,014 $ 57,533 Maturity and interest rate adjustment 3,886 30,781 6,502 31,048 Movement to or extension of interest-rate only payments 38 440 138 440 Interest rate adjustment 26 134 26 134 Forbearance 3,466 33,426 4,687 38,367 Other concession(s) (1) 1,988 15,985 2,031 37,761 Total $ 17,892 $ 135,524 $ 28,398 $ 165,283 (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 periods indicated: Three Months Ended June 30 2017 2016 (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- construction 1 $ 275 $ 275 — $ — $ — Commercial real estate- owner-occupied 1 32 31 3 794 785 Commercial real estate- non-owner-occupied 6 2,721 2,795 6 10,777 10,047 Commercial and industrial 24 9,028 8,551 16 19,496 19,353 Energy-related — — — 19 82,882 100,205 Residential mortgage 6 521 492 10 1,438 1,438 Consumer - home equity 33 4,820 4,807 36 2,750 2,750 Consumer - indirect 23 224 114 — — — Consumer - other 30 832 827 61 946 946 Total 124 $ 18,453 $ 17,892 151 $ 119,083 $ 135,524 Six Months Ended June 30 2017 2016 (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- construction 1 $ 275 $ 275 1 $ 28 $ 26 Commercial real estate- owner-occupied 2 1,730 1,698 5 1,069 1,050 Commercial real estate- non-owner-occupied 11 4,409 4,465 10 11,516 10,749 Commercial and industrial 33 9,254 8,747 28 24,018 23,632 Energy-related — — — 25 110,443 119,890 Residential mortgage 10 780 730 25 4,733 4,692 Consumer - home equity 66 10,851 10,771 57 3,928 3,916 Consumer - indirect 33 360 222 — — — Consumer - other 50 1,547 1,490 85 1,386 1,328 Total 206 $ 29,206 $ 28,398 236 $ 157,121 $ 165,283 Information detailing TDRs that defaulted during the three-month and six-month periods ended June 30, 2017 and 2016, and were modified in the previous twelve months (i.e., the twelve months prior to the default) is presented in the following tables. 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 respective periods, or since the date of modification, whichever is shorter. Three Months Ended June 30 2017 2016 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate- construction — $ — — $ — Commercial real estate- owner-occupied 5 2,297 — — Commercial real estate- non-owner-occupied 9 5,640 4 1,358 Commercial and industrial 17 8,081 5 758 Energy-related — — 1 2,250 Residential mortgage 5 454 4 480 Consumer - home equity 19 1,532 17 1,112 Consumer - indirect automobile 9 75 — — Consumer - other 17 592 34 482 Total 81 $ 18,671 65 $ 6,440 Six Months Ended June 30 2017 2016 (In thousands, except number of loans) Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial real estate- construction 2 $ 132 — $ — Commercial real estate- owner-occupied 7 2,404 — — Commercial real estate- non-owner-occupied 14 6,406 8 1,377 Commercial and industrial 25 8,239 8 3,273 Energy-related — — 1 2,250 Residential mortgage 21 1,854 7 536 Consumer - home equity 37 2,488 24 1,608 Consumer - indirect automobile 33 328 — — Consumer - other 29 893 67 598 Total 168 $ 22,744 115 $ 9,642

Allowance for Credit Losses a28

Allowance for Credit Losses and Credit Quality (Tables)	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Schedule of Allowance for Loan Losses for Covered and Non-Covered Loan Portfolios	A summary of changes in the allowance for credit losses for the six months ended June 30 is as follows: 2017 (Dollars in thousands) Legacy Loans Acquired Loans Total Allowance for credit losses Allowance for loan losses at beginning of period $ 105,569 $ 39,150 $ 144,719 Provision for (Reversal of) loan losses 18,315 (111 ) 18,204 Transfer of balance to OREO and other — 258 258 Loans charged-off (18,098 ) (1,382 ) (19,480 ) Recoveries 1,824 700 2,524 Allowance for loan losses at end of period $ 107,610 $ 38,615 $ 146,225 Reserve for unfunded commitments at beginning of period $ 11,241 $ — $ 11,241 Provision for (Reversal of) unfunded lending commitments (779 ) — (779 ) Reserve for unfunded commitments at end of period $ 10,462 $ — $ 10,462 Allowance for credit losses at end of period $ 118,072 $ 38,615 $ 156,687 2016 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 28,390 (2,416 ) 25,974 Adjustment attributable to FDIC loss share arrangements — 797 797 Net provision for (Reversal of) loan losses 28,390 (1,619 ) 26,771 Adjustment attributable to FDIC loss share arrangements — (797 ) (797 ) Transfer of balance to OREO and other — (967 ) (967 ) Loans charged-off (17,359 ) (1,196 ) (18,555 ) Recoveries 2,022 600 2,622 Allowance for loan losses at end of period $ 106,861 $ 40,591 $ 147,452 Reserve for unfunded commitments at beginning of period $ 14,145 $ — $ 14,145 Provision for (Reversal of) unfunded lending commitments (319 ) — (319 ) Reserve for unfunded commitments at end of period $ 13,826 $ — $ 13,826 Allowance for credit losses at end of period $ 120,687 $ 40,591 $ 161,278 A summary of changes in the allowance for credit losses for legacy loans, by loan portfolio type, for the six months ended June 30 is as follows: 2017 (Dollars in thousands) Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage Consumer Total Allowance for loan losses at beginning of period $ 25,408 $ 35,434 $ 22,486 $ 3,835 $ 18,406 $ 105,569 Provision for (Reversal of) loan losses 4,323 5,181 3,387 (884 ) 6,308 18,315 Loans charged-off (256 ) (8,366 ) (2,845 ) (45 ) (6,586 ) (18,098 ) Recoveries 189 269 — 77 1,289 1,824 Allowance for loan losses at end of period $ 29,664 $ 32,518 $ 23,028 $ 2,983 $ 19,417 $ 107,610 Reserve for unfunded commitments at beginning of period $ 3,206 $ 3,535 $ 1,003 $ 657 $ 2,840 $ 11,241 Provision for (Reversal of) unfunded commitments 294 (46 ) (856 ) (89 ) (82 ) (779 ) Reserve for unfunded commitments at end of period $ 3,500 $ 3,489 $ 147 $ 568 $ 2,758 $ 10,462 Allowance on loans individually evaluated for impairment $ 1,316 $ 7,192 $ 16,094 $ 137 $ 2,181 $ 26,920 Allowance on loans collectively evaluated for impairment 28,348 25,326 6,934 2,846 17,236 80,690 Loans, net of unearned income: Balance at end of period $ 6,114,930 $ 3,390,699 $ 550,162 $ 970,961 $ 2,466,658 $ 13,493,410 Balance at end of period individually evaluated for impairment 42,204 36,836 89,814 4,631 25,983 199,468 Balance at end of period collectively evaluated for impairment 6,072,726 3,353,863 460,348 966,330 2,440,675 13,293,942 2016 (Dollars in thousands) Commercial Real Estate Commercial and Industrial Energy-related Residential Mortgage 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 (715 ) 5,874 16,819 264 6,148 28,390 Loans charged-off (1,549 ) (1,154 ) (7,715 ) (173 ) (6,768 ) (17,359 ) Recoveries 644 35 — 27 1,316 2,022 Allowance for loan losses at end of period $ 23,038 $ 28,038 $ 32,967 $ 4,065 $ 18,753 $ 106,861 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 (26 ) (60 ) (442 ) (23 ) 232 (319 ) Reserve for unfunded commitments at end of period $ 4,134 $ 3,388 $ 2,223 $ 807 $ 3,274 $ 13,826 Allowance on loans individually evaluated for impairment $ 691 $ 969 $ 11,925 $ 100 $ 800 $ 14,485 Allowance on loans collectively evaluated for impairment 22,347 27,069 21,042 3,965 17,953 92,376 Loans, net of unearned income: Balance at end of period $ 5,097,689 $ 3,027,590 $ 659,510 $ 794,701 $ 2,405,359 $ 11,984,849 Balance at end of period individually evaluated for impairment 26,152 34,298 148,317 3,451 9,140 221,358 Balance at end of period collectively evaluated for impairment 5,071,537 2,993,292 511,193 791,250 2,396,219 11,763,491 A summary of changes in the allowance for loan losses for acquired loans, by loan portfolio type, for the six months ended June 30 is as follows: 2017 (Dollars in thousands) Commercial Commercial Energy-related Residential Consumer Total Allowance for loan losses at beginning of period $ 23,574 $ 3,230 $ 39 $ 7,412 $ 4,895 $ 39,150 Provision for (Reversal of) loan losses 1,407 (46 ) (21 ) (578 ) (873 ) (111 ) Transfer of balance to OREO and other 135 (69 ) — 2 190 258 Loans charged-off (1,026 ) (71 ) — (30 ) (255 ) (1,382 ) Recoveries 145 77 — 65 413 700 Allowance for loan losses at end of period $ 24,235 $ 3,121 $ 18 $ 6,871 $ 4,370 $ 38,615 Allowance on loans individually evaluated for impairment $ 402 $ 678 $ — $ 32 $ 92 $ 1,204 Allowance on loans collectively evaluated for impairment 23,833 2,443 18 6,839 4,278 37,411 Loans, net of unearned income: Balance at end of period $ 1,026,673 $ 293,382 $ 1,806 $ 375,506 $ 365,239 $ 2,062,606 Balance at end of period individually evaluated for impairment 10,225 2,851 — 660 2,856 16,592 Balance at end of period collectively evaluated for impairment 777,865 259,101 1,806 263,596 279,019 1,581,387 Balance at end of period acquired with deteriorated credit quality 238,583 31,430 — 111,250 83,364 464,627 2016 (Dollars in thousands) Commercial Commercial Energy-related Residential 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 (1,804 ) 350 (52 ) 896 (1,009 ) (1,619 ) Increase (Decrease) in FDIC loss share receivable 45 (28 ) — (562 ) (252 ) (797 ) Transfer of balance to OREO and other (880 ) 323 — 22 (432 ) (967 ) Loans charged-off (31 ) (700 ) — — (465 ) (1,196 ) Recoveries 85 112 — 29 374 600 Allowance for loan losses at end of period $ 23,394 $ 2,876 $ 73 $ 8,226 $ 6,022 $ 40,591 Allowance on loans individually evaluated for impairment $ — $ 22 $ — $ 2 $ 44 $ 68 Allowance on loans collectively evaluated for impairment 23,394 2,854 73 8,224 5,978 40,523 Loans, net of unearned income: Balance at end of period $ 1,374,312 $ 408,219 $ 2,524 $ 454,361 $ 498,296 $ 2,737,712 Balance at end of period individually evaluated for impairment 1,145 2,075 — 245 4,412 7,877 Balance at end of period collectively evaluated for impairment 1,038,737 368,283 2,524 321,879 386,080 2,117,503 Balance at end of period acquired with deteriorated credit quality 334,430 37,861 — 132,237 107,804 612,332
Investment in Legacy and Acquired 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, or renewed and underwritten by the Company (legacy loans) and acquired loans. Loan premiums/discounts in the tables below represent the adjustment of 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 June 30, 2017 and December 31, 2016. Credit quality information in the tables below includes total loans acquired (including acquired impaired loans) at the gross loan balance, prior to the application of premiums/discounts, at June 30, 2017 and December 31, 2016. Loan delinquency is the primary credit quality indicator that the Company utilizes to monitor consumer asset quality. Legacy loans June 30, 2017 December 31, 2016 (Dollars in thousands) Pass Special Mention Sub- Doubtful Total Pass Special Mention Sub- Doubtful Total Commercial real estate - construction $ 997,264 $ 7,917 $ 5,298 $ — $ 1,010,479 $ 734,687 $ 2,203 $ 3,871 $ — $ 740,761 Commercial real estate - owner-occupied 1,740,717 39,772 34,210 468 1,815,167 1,738,024 17,542 29,058 — 1,784,624 Commercial real estate- non-owner-occupied 3,251,368 8,696 29,220 — 3,289,284 3,063,470 8,617 25,842 — 3,097,929 Commercial and industrial 3,287,383 42,422 58,527 2,367 3,390,699 3,112,300 29,763 35,199 17,534 3,194,796 Energy-related 373,342 49,097 74,620 53,103 550,162 242,123 80,084 225,724 11,358 559,289 Total $ 9,650,074 $ 147,904 $ 201,875 $ 55,938 $ 10,055,791 $ 8,890,604 $ 138,209 $ 319,694 $ 28,892 $ 9,377,399 Legacy loans June 30, 2017 December 31, 2016 (Dollars in thousands) Current 30+ Days Past Due Total Current 30+ Days Past Due Total Residential mortgage $ 955,343 $ 15,618 $ 970,961 $ 836,509 $ 17,707 $ 854,216 Consumer - home equity 1,819,163 19,678 1,838,841 1,768,763 14,658 1,783,421 Consumer - indirect automobile 89,590 2,516 92,106 127,054 3,994 131,048 Consumer - credit card 85,690 897 86,587 81,602 922 82,524 Consumer - other 444,743 4,381 449,124 462,650 3,666 466,316 Total $ 3,394,529 $ 43,090 $ 3,437,619 $ 3,276,578 $ 40,947 $ 3,317,525 Acquired loans June 30, 2017 December 31, 2016 (Dollars in thousands) Pass Special Sub-standard Doubtful Premium/(Discount) Total Pass Special Sub-standard Doubtful Loss Premium/(Discount) Total Commercial real estate - construction $ 71,157 $ 1,208 $ 3,431 $ 14 $ 13,899 $ 89,709 $ 46,498 $ 459 $ 3,118 $ 2,574 $ — $ 8,759 $ 61,408 Commercial real estate - owner-occupied 384,411 3,275 14,627 — (12,072 ) 390,241 426,492 7,664 17,584 1,356 — (3,084 ) 450,012 Commercial real estate- non-owner-occupied 541,724 3,434 26,188 119 (24,742 ) 546,723 663,571 11,620 31,552 101 23 (39,335 ) 667,532 Commercial and industrial 275,350 5,440 11,315 2,601 (1,324 ) 293,382 323,154 1,416 27,749 494 — (4,487 ) 348,326 Energy-related 1,811 — — — (5 ) 1,806 1,910 — — — — (6 ) 1,904 Total $ 1,274,453 $ 13,357 $ 55,561 $ 2,734 $ (24,244 ) $ 1,321,861 $ 1,461,625 $ 21,159 $ 80,003 $ 4,525 $ 23 $ (38,153 ) $ 1,529,182 Acquired loans June 30, 2017 December 31, 2016 (Dollars in thousands) Current 30+ Days Past Due Premium (Discount) Total Current 30+ Days Past Due Premium (Discount) Total Residential mortgage $ 378,204 $ 22,121 $ (24,819 ) $ 375,506 $ 424,300 $ 20,914 $ (32,030 ) $ 413,184 Consumer - home equity 322,658 13,051 (15,602 ) 320,107 377,021 12,807 (17,323 ) 372,505 Consumer - indirect automobile 24 — — 24 12 — (8 ) 4 Consumer - other 48,168 1,225 (4,285 ) 45,108 58,141 1,423 (4,392 ) 55,172 Total $ 749,054 $ 36,397 $ (44,706 ) $ 740,745 $ 859,474 $ 35,144 $ (53,753 ) $ 840,865
Schedule of Investment in Legacy Impaired Loans	Information on the Company’s investment in legacy impaired loans, which include all TDRs and all other non-accrual loans evaluated or measured individually for impairment for purposes of determining the allowance for loan losses, is presented in the following tables as of and for the periods indicated. June 30, 2017 December 31, 2016 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- construction $ 2,123 $ 2,123 $ — $ 38 $ 38 $ — Commercial real estate- owner-occupied 13,932 13,932 — 4,593 4,593 — Commercial real estate- non-owner-occupied 4,443 4,443 — 12,668 11,876 — Commercial and industrial 16,016 16,016 — 14,202 13,189 — Energy-related 32,013 32,013 — 152,424 143,239 — Residential mortgage 1,123 1,123 — — — — Consumer - home equity 3,336 3,336 — — — — Consumer -other — — — — — — With an allowance recorded: Commercial real estate- construction 36 36 (1 ) — — — Commercial real estate- owner-occupied 17,945 17,945 (690 ) 17,580 17,429 (640 ) Commercial real estate- non-owner-occupied 3,725 3,725 (625 ) 108 95 (1 ) Commercial and industrial 20,820 20,820 (7,192 ) 28,829 28,329 (10,864 ) Energy-related 57,801 57,801 (16,094 ) 53,967 53,088 (9,769 ) Residential mortgage 3,543 3,508 (137 ) 4,627 4,312 (144 ) Consumer - home equity 18,865 18,757 (1,805 ) 13,906 13,257 (993 ) Consumer - indirect automobile 668 668 (83 ) 1,037 758 (114 ) Consumer - other 3,222 3,222 (293 ) 2,447 2,442 (251 ) Total $ 199,611 $ 199,468 $ (26,920 ) $ 306,426 $ 292,645 $ (22,776 ) Total commercial loans $ 168,854 $ 168,854 $ (24,602 ) $ 284,409 $ 271,876 $ (21,274 ) Total mortgage loans 4,666 4,631 (137 ) 4,627 4,312 (144 ) Total consumer loans 26,091 25,983 (2,181 ) 17,390 16,457 (1,358 ) Three Months Ended June 30, 2017 Three Months Ended June 30, 2016 Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 Average Interest Average Interest Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded: Commercial real estate- construction $ 2,123 $ 13 $ 27 $ — $ 2,123 $ 39 $ 30 $ — Commercial real estate- owner-occupied 14,054 158 2,072 20 14,179 404 2,085 41 Commercial real estate- non-owner-occupied 4,409 39 13,395 123 4,433 67 13,454 237 Commercial and industrial 21,116 106 36,212 467 21,998 232 41,074 947 Energy-related 32,370 44 106,692 912 34,330 102 102,364 1,857 Residential mortgage 1,130 12 825 10 1,136 24 825 19 Consumer - home equity 3,347 32 — — 3,356 65 — — With an allowance recorded: Commercial real estate- construction 37 1 — — 37 1 — — Commercial real estate- owner-occupied 17,908 86 10,636 83 17,998 186 10,694 166 Commercial real estate- non-owner-occupied 3,761 13 53 — 3,774 57 60 1 Commercial and industrial 21,028 284 2,125 23 21,504 555 2,191 48 Energy-related 58,399 2 15,486 10 58,868 4 12,290 47 Residential mortgage 3,528 34 2,642 18 3,549 68 2,657 38 Consumer - home equity 18,359 196 7,550 74 17,443 375 7,290 146 Consumer - indirect automobile 750 6 650 6 797 14 723 18 Consumer - other 3,100 51 846 15 2,921 96 702 25 Total $ 205,419 $ 1,077 $ 199,211 $ 1,761 $ 208,446 $ 2,289 $ 196,439 $ 3,590 Total commercial loans $ 175,205 $ 746 $ 186,698 $ 1,638 $ 179,244 $ 1,647 $ 184,242 $ 3,344 Total mortgage loans 4,658 46 3,467 28 4,685 92 3,482 57 Total consumer loans 25,556 285 9,046 95 24,517 550 8,715 189

Goodwill and Other Intangible29

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Carrying Amount of Goodwill	Changes to the carrying amount of goodwill by reporting unit for the six months ended June 30, 2017, and the year ended December 31, 2016 are provided in the following table. (Dollars in thousands) IBERIABANK IMC LTC Total Balance, December 31, 2015 $ 696,260 $ 23,178 $ 5,165 $ 724,603 Goodwill adjustments during the year 2,253 — — 2,253 Balance, December 31, 2016 $ 698,513 $ 23,178 $ 5,165 $ 726,856 Goodwill adjustments during the year — — — — Balance, June 30, 2017 $ 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: June 30, 2017 December 31, 2016 (Dollars in thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core deposit intangibles $ 74,001 $ (55,501 ) $ 18,500 $ 74,001 $ (52,165 ) $ 21,836 Customer relationship intangible asset 1,143 (942 ) 201 1,348 (1,064 ) 284 Non-compete agreement 63 (31 ) 32 63 (22 ) 41 Total $ 75,207 $ (56,474 ) $ 18,733 $ 75,412 $ (53,251 ) $ 22,161
Schedule of Amortization Expense of 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: June 30, 2017 December 31, 2016 (Dollars in thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Core deposit intangibles $ 74,001 $ (55,501 ) $ 18,500 $ 74,001 $ (52,165 ) $ 21,836 Customer relationship intangible asset 1,143 (942 ) 201 1,348 (1,064 ) 284 Non-compete agreement 63 (31 ) 32 63 (22 ) 41 Total $ 75,207 $ (56,474 ) $ 18,733 $ 75,412 $ (53,251 ) $ 22,161
Schedule of Mortgage Servicing Rights	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: June 30, 2017 December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) Mortgage servicing rights $ 8,265 $ (3,576 ) $ 4,689 $ 7,202 $ (3,144 ) $ 4,058

Derivative Instruments and Ot30

Derivative Instruments and Other Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Derivative Instruments	Information pertaining to outstanding derivative instruments is as follows: Balance Sheet Location Derivative Assets - Fair Value Balance Sheet Location Derivative Liabilities - Fair Value (Dollars in thousands) June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 Derivatives designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ — $ — Other liabilities $ 1,041 $ 525 Total derivatives designated as hedging instruments under ASC Topic 815 $ — $ — $ 1,041 $ 525 Derivatives not designated as hedging instruments under ASC Topic 815: Interest rate contracts Other assets $ 20,432 $ 20,719 Other liabilities $ 18,384 $ 20,719 Foreign exchange contracts Other assets 73 27 Other liabilities 73 26 Forward sales contracts Other assets 860 6,014 Other liabilities 706 794 Written and purchased options Other assets 11,535 12,125 Other liabilities 8,439 8,098 Other contracts Other assets — 1 Other liabilities 41 47 Total derivatives not designated as hedging instruments under ASC Topic 815 $ 32,900 $ 38,886 $ 27,643 $ 29,684 Total $ 32,900 $ 38,886 $ 28,684 $ 30,209 Derivative Assets - Notional Amount Derivative Liabilities - Notional Amount (Dollars in thousands) June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 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 $ 1,120,278 $ 1,033,955 $ 1,120,278 $ 1,033,955 Foreign exchange contracts 1,724 4,474 1,724 4,474 Forward sales contracts 214,925 229,181 131,915 120,567 Written and purchased options 369,582 289,115 177,921 154,170 Other contracts 8,630 8,784 103,055 106,518 Total derivatives not designated as hedging instruments under ASC Topic 815 $ 1,715,139 $ 1,565,509 $ 1,534,893 $ 1,419,684 Total $ 1,715,139 $ 1,565,509 $ 1,643,393 $ 1,528,184
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. June 30, 2017 Gross Amounts Presented in the Balance Sheet Gross Amounts Not Offset in the Balance Sheet Net (Dollars in thousands) Derivatives Collateral (1) Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 20,432 $ (8,747 ) $ — $ 11,685 Written and purchased options 8,329 — — 8,329 Total derivative assets subject to master netting arrangements $ 28,761 $ (8,747 ) $ — $ 20,014 Derivative liabilities Interest rate contracts designated as hedging instruments $ 1,041 $ — $ — $ 1,041 Interest rate contracts not designated as hedging instruments 18,384 (8,747 ) (1,513 ) 8,124 Total derivative liabilities subject to master netting arrangements $ 19,425 $ (8,747 ) $ (1,513 ) $ 9,165 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities . December 31, 2016 Gross Amounts Presented in the Balance Sheet Gross Amounts Not Offset in the Balance Sheet Net (Dollars in thousands) Derivatives Collateral (1) Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 20,719 $ (9,677 ) $ — $ 11,042 Written and purchased options 8,085 — — 8,085 Total derivative assets subject to master netting arrangements $ 28,804 $ (9,677 ) $ — $ 19,127 Derivative liabilities Interest rate contracts designated as hedging instruments $ 525 $ — $ (181 ) $ 344 Interest rate contracts not designated as hedging instruments 20,719 (9,677 ) (1,711 ) 9,331 Total derivative liabilities subject to master netting arrangements $ 21,244 $ (9,677 ) $ (1,892 ) $ 9,675 (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. June 30, 2017 Gross Amounts Presented in the Balance Sheet Gross Amounts Not Offset in the Balance Sheet Net (Dollars in thousands) Derivatives Collateral (1) Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 20,432 $ (8,747 ) $ — $ 11,685 Written and purchased options 8,329 — — 8,329 Total derivative assets subject to master netting arrangements $ 28,761 $ (8,747 ) $ — $ 20,014 Derivative liabilities Interest rate contracts designated as hedging instruments $ 1,041 $ — $ — $ 1,041 Interest rate contracts not designated as hedging instruments 18,384 (8,747 ) (1,513 ) 8,124 Total derivative liabilities subject to master netting arrangements $ 19,425 $ (8,747 ) $ (1,513 ) $ 9,165 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities . December 31, 2016 Gross Amounts Presented in the Balance Sheet Gross Amounts Not Offset in the Balance Sheet Net (Dollars in thousands) Derivatives Collateral (1) Derivatives subject to master netting arrangements Derivative assets Interest rate contracts not designated as hedging instruments $ 20,719 $ (9,677 ) $ — $ 11,042 Written and purchased options 8,085 — — 8,085 Total derivative assets subject to master netting arrangements $ 28,804 $ (9,677 ) $ — $ 19,127 Derivative liabilities Interest rate contracts designated as hedging instruments $ 525 $ — $ (181 ) $ 344 Interest rate contracts not designated as hedging instruments 20,719 (9,677 ) (1,711 ) 9,331 Total derivative liabilities subject to master netting arrangements $ 21,244 $ (9,677 ) $ (1,892 ) $ 9,675 (1) Consists of cash collateral recorded at cost, which approximates fair value, and investment securities.
Effect of Derivatives on the Consolidated Financial Statements	At June 30, 2017 and 2016 , and for the three and six 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 net of taxes (Effective Portion) (Dollars in thousands) For the Three Months Ended June 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2017 2016 2017 2016 2017 2016 Interest rate contracts $ (790 ) $ (2,328 ) Other income (expense) $ (103 ) $ — Other income (expense) $ — $ — Total $ (790 ) $ (2,328 ) $ (103 ) $ — $ — $ — 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 net of taxes (Effective Portion) (Dollars in thousands) For the Six Months Ended June 30 Derivatives in ASC Topic 815 Cash Flow Hedging Relationships 2017 2016 2017 2016 2017 2016 Interest rate contracts $ (627 ) $ (6,455 ) Other income (expense) $ (148 ) $ — Other income (expense) $ — $ — Total $ (627 ) $ (6,455 ) $ (148 ) $ — $ — $ — At June 30, 2017 and 2016, and for the three and six months then ended, information pertaining to the effect of derivatives not designated as hedging instruments on the consolidated financial statements is as follows: Location of Gain (Loss) Recognized in Income on Derivatives Amount of Gain (Loss) Recognized in Income on Derivatives For the Three Months Ended June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Interest rate contracts (1) Other income $ 1,299 $ 2,332 $ 2,416 $ 5,294 Foreign exchange contracts Other income 7 2 14 3 Forward sales contracts Mortgage income (1,526 ) (4,787 ) (1,886 ) (10,130 ) Written and purchased options Mortgage income (1,586 ) 2,488 (931 ) 6,470 Other contracts Other income 5 — 9 — Total $ (1,801 ) $ 35 $ (378 ) $ 1,637

Shareholders' Equity, Capital31

Shareholders' Equity, Capital Ratios and Other Regulatory Matters (Tables)	6 Months Ended
	Jun. 30, 2017
Banking and Thrift [Abstract]
Schedule of Preferred Stock	The following table presents a summary of the Company's non-cumulative perpetual preferred stock: June 30, 2017 December 31, 2016 Issuance Date Earliest Redemption Date Annual Dividend Rate Liquidation Amount Carrying Amount Carrying Amount (Dollars in thousands) Series B Preferred Stock 8/5/2015 8/1/2025 6.625 % $ 80,000 $ 76,812 $ 76,812 Series C Preferred Stock 5/9/2016 5/1/2026 6.600 % 57,500 55,285 55,285 $ 137,500 $ 132,097 $ 132,097
Actual Capital Amounts and Ratios	The Company’s and IBERIABANK’s actual capital amounts and ratios as of June 30, 2017 and December 31, 2016 are presented in the following table. (Dollars in thousands) June 30, 2017 Minimum Well-Capitalized Actual Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 845,167 4.00 % N/A N/A $ 2,787,729 13.19 % IBERIABANK 842,313 4.00 1,052,892 5.00 1,994,073 9.47 Common Equity Tier 1 (CET1) (1) Consolidated $ 822,980 4.50 % N/A N/A $ 2,655,632 14.52 % IBERIABANK 820,978 4.50 1,185,857 6.50 1,994,073 10.93 Tier 1 Risk-Based Capital (1) Consolidated $ 1,097,306 6.00 % N/A N/A $ 2,787,729 15.24 % IBERIABANK 1,094,637 6.00 1,459,516 8.00 1,994,073 10.93 Total Risk-Based Capital (1) Consolidated $ 1,463,075 8.00 % N/A N/A $ 3,060,916 16.74 % IBERIABANK 1,459,516 8.00 1,824,395 10.00 2,150,760 11.79 December 31, 2016 Minimum Well-Capitalized Actual Amount Ratio Amount Ratio Amount Ratio Tier 1 Leverage Consolidated $ 818,440 4.00 % N/A N/A $ 2,221,528 10.86 % IBERIABANK 816,152 4.00 1,020,190 5.00 1,878,703 9.21 Common Equity Tier 1 (CET1) (1) Consolidated $ 794,334 4.50 % N/A N/A $ 2,089,431 11.84 % IBERIABANK 792,111 4.50 1,144,160 6.50 1,878,703 10.67 Tier 1 Risk-Based Capital (1) Consolidated $ 1,059,112 6.00 % N/A N/A $ 2,221,528 12.59 % IBERIABANK 1,056,147 6.00 1,408,197 8.00 1,878,703 10.67 Total Risk-Based Capital (1) Consolidated $ 1,412,149 8.00 % N/A N/A $ 2,493,988 14.13 % IBERIABANK 1,408,197 8.00 1,760,246 10.00 2,034,663 11.56 (1) Minimum capital ratios are subject to a capital conservation buffer. In order to avoid limitations on distributions, including dividend payments, and certain discretionary bonus payments to executive officers, an institution must hold a capital conservation buffer above its minimum risk-based capital requirements. This capital conservation buffer is calculated as the lowest of the differences between the actual CET1 ratio, Tier 1 Risk-Based Capital Ratio, and Total Risk-Based Capital ratio and the corresponding minimum ratios.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2017
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 June 30, Six Months Ended June 30, (In thousands, except per share data) 2017 2016 2017 2016 Earnings per common share - basic: Net income $ 52,018 $ 50,810 $ 102,491 $ 93,579 Preferred stock dividends (949 ) (854 ) (4,548 ) (3,430 ) Dividends and undistributed earnings allocated to unvested restricted shares (361 ) (540 ) (707 ) (1,003 ) Net income allocated to common shareholders - basic $ 50,708 $ 49,416 $ 97,236 $ 89,146 Weighted average common shares outstanding 50,630 40,771 48,389 40,741 Earnings per common share - basic 1.00 1.21 2.01 2.19 Earnings per common share - diluted: Net income allocated to common shareholders - basic $ 50,708 $ 49,416 $ 97,236 $ 89,146 Dividends and undistributed earnings allocated to unvested restricted shares (2 ) (12 ) (39 ) (13 ) Net income allocated to common shareholders - diluted $ 50,706 $ 49,404 $ 97,197 $ 89,133 Weighted average common shares outstanding 50,630 40,771 48,389 40,741 Dilutive potential common shares 354 137 362 86 Weighted average common shares outstanding - diluted 50,984 40,908 48,751 40,827 Earnings per common share - diluted $ 0.99 $ 1.21 $ 1.99 $ 2.18

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award	The following table represents unvested restricted stock award and restricted share unit activity for the following periods: For the Six Months Ended June 30 2017 2016 Balance at beginning of period 543,258 507,130 Granted 163,353 240,699 Forfeited (9,951 ) (9,040 ) Earned and issued (185,092 ) (172,356 ) Balance at end of period 511,568 566,433 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 192,359 11,490 Forfeited share equivalents (16,283 ) 973 Vested share equivalents (147,511 ) 7,452 Balance, June 30, 2016 490,995 $ 29,327 Balance, December 31, 2016 472,830 $ 39,600 Granted 105,048 8,561 Forfeited share equivalents (15,104 ) 1,231 Vested share equivalents (150,409 ) 14,246 Balance, June 30, 2017 412,365 $ 33,608 (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 $81.50 and $59.73 on June 30, 2017, and 2016, respectively. 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 149,932 47.46 Exercised (8,811 ) 55.62 Forfeited or expired (45,723 ) 60.97 Outstanding options, June 30, 2016 909,175 $ 55.23 Exercisable options, June 30, 2016 598,469 $ 56.31 Outstanding options, December 31, 2016 721,538 $ 55.38 Granted 71,491 85.42 Exercised (64,163 ) 55.05 Forfeited or expired (15,091 ) 74.72 Outstanding options, June 30, 2017 713,775 $ 58.01 Exercisable options, June 30, 2017 470,841 $ 55.79
Schedule of Valuation Assumptions	The following weighted-average assumptions were used for option awards issued during the following periods: For the Six Months Ended June 30 2017 2016 Expected dividends 1.7 % 2.9 % Expected volatility 24.9 % 29.1 % Risk-free interest rate 2.1 % 1.4 % Expected term (in years) 5.6 6.5 Weighted-average grant-date fair value $ 18.76 $ 10.10
Schedule of Allocation for Share-based Compensation Expense	The following table represents the compensation expense that was included in non-interest expense and related income tax benefits 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 June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Compensation expense related to restricted stock awards and restricted share units $ 3,045 $ 3,329 $ 6,322 $ 6,715 Income tax benefit related to restricted stock awards and restricted share units 1,066 1,165 2,213 2,350 The following table represents the compensation expense that is included in non-interest expense and related income tax benefits in the accompanying consolidated statements of comprehensive income related to stock options for the following periods: For the Three Months Ended June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Compensation expense related to stock options $ 344 $ 502 $ 789 $ 987 Income tax benefit related to stock options 47 81 115 162 The following table indicates compensation expense recorded for phantom stock and performance units based on the number of share equivalents vested at June 30 of the years indicated and the current market price of the Company’s stock at that time: For the Three Months Ended June 30 For the Six Months Ended June 30 (Dollars in thousands) 2017 2016 2017 2016 Compensation expense related to phantom stock and performance units $ 2,889 $ 2,793 $ 5,942 $ 5,198

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
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 Annual Report on Form 10-K for the year ended December 31, 2016, for a description of how fair value measurements are determined. June 30, 2017 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 4,009,299 $ — $ 4,009,299 Mortgage loans held for sale — 140,959 — 140,959 Derivative instruments — 32,900 — 32,900 Total $ — $ 4,183,158 $ — $ 4,183,158 Liabilities Derivative instruments $ — $ 28,684 $ — $ 28,684 Total $ — $ 28,684 $ — $ 28,684 December 31, 2016 Level 1 Level 2 Level 3 Total Assets Securities available for sale $ — $ 3,446,097 $ — $ 3,446,097 Mortgage loans held for sale — 157,041 — 157,041 Derivative instruments — 38,886 — 38,886 Total $ — $ 3,642,024 $ — $ 3,642,024 Liabilities Derivative instruments $ — $ 30,209 $ — $ 30,209 Total $ — $ 30,209 $ — $ 30,209
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. June 30, 2017 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 97,363 $ 97,363 OREO, net — — 2,871 2,871 Total $ — $ — $ 100,234 $ 100,234 December 31, 2016 (Dollars in thousands) Level 1 Level 2 Level 3 Total Assets Loans $ — $ — $ 93,485 $ 93,485 OREO, net — — 185 185 Total $ — $ — $ 93,670 $ 93,670
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: June 30, 2017 December 31, 2016 (Dollars in thousands) Aggregate Fair Value Aggregate Unpaid Principal Aggregate Fair Value Less Unpaid Principal Aggregate Fair Value Aggregate Unpaid Principal Aggregate Fair Value Less Unpaid Principal Mortgage loans held for sale, at fair value $ 140,959 $ 137,524 $ 3,435 $ 157,041 $ 153,801 $ 3,240

Fair Value of Financial Instr35

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
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 2016 Annual Report on Form 10-K for the year ended December 31, 2016 for a description of how fair value measurements are determined. June 30, 2017 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 469,360 $ 469,360 $ 469,360 $ — $ — Investment securities 4,093,816 4,094,747 — 4,094,747 — Loans and loans held for sale, net of unearned income and allowance for loan losses 15,550,750 15,667,569 — 140,959 15,526,610 Derivative instruments 32,900 32,900 — 32,900 — Financial Liabilities Deposits $ 16,853,116 $ 15,817,343 $ — $ — $ 15,817,343 Short-term borrowings 583,935 583,935 333,935 250,000 — Long-term debt 667,243 658,483 — — 658,483 Derivative instruments 28,684 28,684 — 28,684 — December 31, 2016 (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial Assets Cash and cash equivalents $ 1,362,126 $ 1,362,126 $ 1,362,126 $ — $ — Investment securities 3,535,313 3,536,029 — 3,536,029 — Loans and loans held for sale, net of unearned income and allowance for loan losses 15,077,293 15,066,055 — 157,041 14,909,014 Derivative instruments 38,886 38,886 — 38,886 — Financial Liabilities Deposits $ 17,408,283 $ 16,762,475 $ — $ — $ 16,762,475 Short-term borrowings 509,136 509,136 334,136 175,000 — Long-term debt 628,953 617,656 — — 617,656 Derivative instruments 30,209 30,209 — 30,209 —

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	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 June 30, 2017 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 202,694 $ 1,881 $ — $ 204,575 Interest expense 20,932 — — 20,932 Net interest income 181,762 1,881 — 183,643 Provision for/(reversal of) loan losses 12,134 (84 ) — 12,050 Mortgage income — 19,730 — 19,730 Service charges on deposit accounts 11,410 — — 11,410 Title revenue — — 6,190 6,190 Other non-interest income 18,647 (11 ) — 18,636 Allocated expenses (3,322 ) 2,490 832 — Non-interest expense 120,698 22,417 4,393 147,508 Income/(loss) before income tax expense 82,309 (3,223 ) 965 80,051 Income tax expense/(benefit) 28,745 (1,094 ) 382 28,033 Net income/(loss) $ 53,564 $ (2,129 ) $ 583 $ 52,018 Total loans and loans held for sale, net of unearned income $ 15,504,171 $ 192,804 $ — $ 15,696,975 Total assets 21,549,557 215,862 25,308 21,790,727 Total deposits 16,852,620 496 — 16,853,116 Average assets 21,593,026 226,326 24,185 21,843,537 Three Months Ended June 30, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 176,564 $ 2,130 $ — $ 178,694 Interest expense 14,782 1,159 — 15,941 Net interest income 161,782 971 — 162,753 Provision for loan losses 11,866 — — 11,866 Mortgage income 7 25,984 — 25,991 Service charges on deposit accounts 10,940 — — 10,940 Title revenue — — 6,135 6,135 Other non-interest income 21,843 8 — 21,851 Allocated expenses (3,885 ) 2,947 938 — Non-interest expense 120,268 14,820 4,416 139,504 Income/(loss) before income tax expense 66,323 9,196 781 76,300 Income tax expense/(benefit) 21,558 3,625 307 25,490 Net income/(loss) $ 44,765 $ 5,571 $ 474 $ 50,810 Total loans and loans held for sale, net of unearned income $ 14,702,843 $ 249,371 $ — $ 14,952,214 Total assets 19,807,507 326,397 26,951 20,160,855 Total deposits 15,855,908 6,119 — 15,862,027 Average assets 19,668,456 308,647 26,814 20,003,917 Six Months Ended June 30, 2017 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 393,517 $ 3,590 $ 1 $ 397,108 Interest expense 40,647 — — 40,647 Net interest income 352,870 3,590 1 356,461 Provision for/(reversal of) loan losses 18,292 (88 ) — 18,204 Mortgage income — 33,845 — 33,845 Service charges on deposit accounts 22,563 — — 22,563 Title revenue — — 10,931 10,931 Other non-interest income 36,000 (21 ) (6 ) 35,973 Allocated expenses (5,496 ) 4,146 1,350 — Non-interest expense 242,349 37,584 8,593 288,526 Income/(loss) before income tax expense 156,288 (4,228 ) 983 153,043 Income tax expense/(benefit) 51,574 (1,416 ) 394 50,552 Net income/(loss) $ 104,714 $ (2,812 ) $ 589 $ 102,491 Total loans and loans held for sale, net of unearned income $ 15,504,171 $ 192,804 $ — $ 15,696,975 Total assets 21,549,557 215,862 25,308 21,790,727 Total deposits 16,852,620 496 — 16,853,116 Average assets 21,572,094 256,343 24,032 21,852,469 Six Months Ended June 30, 2016 (Dollars in thousands) IBERIABANK IMC LTC Consolidated Interest and dividend income $ 351,888 $ 3,741 $ 1 $ 355,630 Interest expense 29,436 2,038 — 31,474 Net interest income 322,452 1,703 1 324,156 Provision for loan losses 26,771 — — 26,771 Mortgage income 6 45,925 — 45,931 Service charges on deposit accounts 21,891 — — 21,891 Title revenue — — 10,880 10,880 Other non-interest income 42,053 7 — 42,060 Allocated expenses (6,554 ) 4,997 1,557 — Non-interest expense 240,295 28,018 8,643 276,956 Income/(loss) before income tax expense 125,890 14,620 681 141,191 Income tax expense/(benefit) 41,559 5,778 275 47,612 Net income/(loss) $ 84,331 $ 8,842 $ 406 $ 93,579 Total loans and loans held for sale, net of unearned income $ 14,702,843 $ 249,371 $ — $ 14,952,214 Total assets 19,807,507 326,397 26,951 20,160,855 Total deposits 15,855,908 6,119 — 15,862,027 Average assets 19,525,087 280,464 27,063 19,832,614

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of Financial Instruments Outstanding	At June 30, 2017 and December 31, 2016, respectively, the Company had the following financial instruments outstanding and related reserves, whose contract amounts represent credit risk: (Dollars in thousands) June 30, 2017 December 31, 2016 Commitments to grant loans $ 518,934 $ 355,558 Unfunded commitments under lines of credit 5,051,175 4,899,930 Commercial and standby letters of credit 183,031 163,560 Reserve for unfunded lending commitments 10,462 11,241

Summary of Significant Accoun38

Summary of Significant Accounting Policies (Detail) $ in Thousands	Jun. 30, 2017USD ($)State	Dec. 31, 2016USD ($)
Schedule Of Significant Accounting Policies
Maximum loss exposure related to unconsolidated VIE's | $	$ 94,000	$ 91,000
Other assets | $	$ 631,778	$ 651,229
IBERIABANK Corporation
Schedule Of Significant Accounting Policies
Number of operating states | State	8
IMC
Schedule Of Significant Accounting Policies
Number of operating states | State	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	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities
Amortized cost	$ 4,029,655	$ 3,486,274
Gross unrealized gain	13,329	7,374
Gross unrealized losses	(33,685)	(47,551)
Estimated fair value	4,009,299	3,446,097
Schedule of Held-to-maturity Securities
Amortized cost	84,517	89,216
Gross unrealized gains	1,639	1,666
Gross unrealized losses	(708)	(950)
Estimated fair value	85,448	89,932
Fair value of securities held as collateral	1,700,000	1,500,000
U.S. Government-Sponsored Enterprise Obligations
Schedule of Available-for-sale Securities
Amortized cost	161,544	212,662
Gross unrealized gain	164	245
Gross unrealized losses	(317)	(549)
Estimated fair value	161,391	212,358
Obligations of State and Political Subdivisions
Schedule of Available-for-sale Securities
Amortized cost	296,062	286,458
Gross unrealized gain	5,902	1,948
Gross unrealized losses	(1,694)	(5,207)
Estimated fair value	300,270	283,199
Schedule of Held-to-maturity Securities
Amortized cost	61,342	64,726
Gross unrealized gains	1,588	1,609
Gross unrealized losses	(57)	(133)
Estimated fair value	62,873	66,202
Mortgage-Backed Securities
Schedule of Available-for-sale Securities
Amortized cost	3,464,253	2,888,180
Gross unrealized gain	6,597	4,820
Gross unrealized losses	(31,118)	(41,291)
Estimated fair value	3,439,732	2,851,709
Schedule of Held-to-maturity Securities
Amortized cost	23,175	24,490
Gross unrealized gains	51	57
Gross unrealized losses	(651)	(817)
Estimated fair value	22,575	23,730
Other Securities
Schedule of Available-for-sale Securities
Amortized cost	107,796	98,974
Gross unrealized gain	666	361
Gross unrealized losses	(556)	(504)
Estimated fair value	$ 107,906	$ 98,831

Investment Securities - Sched40

Investment Securities - Schedule of Securities with Gross Unrealized Losses Aggregated by Investment Category (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Gross Unrealized Losses
Less than twelve months	$ (30,200)	$ (44,874)
Over twelve months	(3,485)	(2,677)
Total	(33,685)	(47,551)
Estimated Fair Value
Less than twelve months	2,562,038	2,526,660
Over twelve months	171,114	102,762
Total	2,733,152	2,629,422
Gross Unrealized Losses
Less than twelve months	(257)	(463)
Over twelve months	(451)	(487)
Total	(708)	(950)
Estimated Fair Value
Less than twelve months	16,858	22,890
Over twelve months	10,308	10,960
Total	27,166	33,850
U.S. Government-Sponsored Enterprise Obligations
Gross Unrealized Losses
Less than twelve months	(317)	(549)
Over twelve months	0	0
Total	(317)	(549)
Estimated Fair Value
Less than twelve months	110,276	150,554
Over twelve months	0	0
Total	110,276	150,554
Obligations of State and Political Subdivisions
Gross Unrealized Losses
Less than twelve months	(1,580)	(5,207)
Over twelve months	(114)	0
Total	(1,694)	(5,207)
Estimated Fair Value
Less than twelve months	82,187	148,059
Over twelve months	4,541	0
Total	86,728	148,059
Mortgage-Backed Securities
Gross Unrealized Losses
Less than twelve months	(27,763)	(38,667)
Over twelve months	(3,355)	(2,624)
Total	(31,118)	(41,291)
Estimated Fair Value
Less than twelve months	2,330,909	2,191,563
Over twelve months	165,156	98,912
Total	2,496,065	2,290,475
Other Securities
Gross Unrealized Losses
Less than twelve months	(540)	(451)
Over twelve months	(16)	(53)
Total	(556)	(504)
Estimated Fair Value
Less than twelve months	38,666	36,484
Over twelve months	1,417	3,850
Total	40,083	40,334
Obligations of State and Political Subdivisions
Gross Unrealized Losses
Less than twelve months	(57)	(133)
Over twelve months	0	0
Total	(57)	(133)
Estimated Fair Value
Less than twelve months	5,014	10,602
Over twelve months	0	0
Total	5,014	10,602
Mortgage-Backed Securities
Gross Unrealized Losses
Less than twelve months	(200)	(330)
Over twelve months	(451)	(487)
Total	(651)	(817)
Estimated Fair Value
Less than twelve months	11,844	12,288
Over twelve months	10,308	10,960
Total	$ 22,152	$ 23,248

Investment Securities - Additio

Investment Securities - Additional Information on Securities in a Continuous Loss Position (Detail) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017USD ($)Security	Dec. 31, 2016USD ($)Security
Schedule of Available-for-sale Securities
Number of debt securities with unrealized losses | Security	386	397
Debt securities with unrealized losses (percentage of amortized cost)	1.23%	1.79%
Number of securities | Security	45	31
Amortized cost basis	$ 185,358	$ 116,886
Unrealized loss	$ 3,936	$ 3,164
Fannie Mae, Freddie Mac, or Ginnie Mae
Schedule of Available-for-sale Securities
Number of securities | Security	43	28
Amortized cost basis	$ 183,926	$ 112,983
Unrealized loss	$ 3,920	$ 3,111
Other
Schedule of Available-for-sale Securities
Number of securities | Security	2	3
Amortized cost basis	$ 1,432	$ 3,903
Unrealized loss	$ 16	$ 53

Investment Securities - Sched42

Investment Securities - Schedule of Amortized Cost and Estimated Fair Value of Investment Securities by Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Weighted Average Yield
Within one year or less	1.61%
One through five years	1.78%
After five through ten years	2.34%
Over ten years	2.27%
Weighted average yield	2.25%
Amortized Cost
Within one year or less	$ 22,066
One through five years	250,400
After five through ten years	837,818
Over ten years	2,919,371
Amortized cost	4,029,655
Estimated Fair Value
Within one year or less	22,008
One through five years	250,806
After five through ten years	840,128
Over ten years	2,896,357
Estimated fair value	$ 4,009,299	$ 3,446,097
Weighted Average Yield
Within one year or less	2.65%
One through five years	2.75%
After five through ten years	3.24%
Over ten years	2.98%
Weighted average yield	3.01%
Amortized Cost
Within one year or less	$ 1,622
One through five years	10,234
After five through ten years	21,161
Over ten years	51,500
Amortized cost	84,517	89,216
Estimated Fair Value
Within one year or less	1,626
One through five years	10,378
After five through ten years	21,836
Over ten years	51,608
Estimated fair value	$ 85,448	$ 89,932

Investment Securities - Sched43

Investment Securities - Schedule of Realized Gains and Losses from Sale of Securities Classified as Available for Sale (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Realized gains	$ 242	$ 2,473	$ 242	$ 2,935
Realized losses	(183)	(684)	(183)	(950)
Net realized gains (losses)	$ 59	$ 1,789	$ 59	$ 1,985

Investment Securities - Sched44

Investment Securities - Schedule of Securities in Other Assets on Company's Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Federal Home Loan Bank (FHLB) stock	$ 38,539	$ 42,326
Federal Reserve Bank Stock	48,584	48,584
Other Investments	3,008	2,808
Marketable Securities, Equity Securities	$ 90,131	$ 93,718

Loans - Schedule of Non-Covered

Loans - Schedule of Non-Covered Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	$ 15,556,016	$ 15,064,971
Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	11,377,652	10,906,581
Commercial Loans | Commercial real estate- construction
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,100,188	802,169
Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	2,205,408	2,234,636
Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	3,836,007	3,765,461
Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	3,684,081	3,543,122
Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	551,968	561,193
Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,346,467	1,267,400
Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	2,831,897	2,890,990
Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	2,158,948	2,155,926
Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	92,130	131,052
Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	580,819	604,012
Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	13,493,410	12,694,924
Legacy Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	10,055,791	9,377,399
Legacy Loans | Commercial Loans | Commercial real estate- construction
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,010,479	740,761
Legacy Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,815,167	1,784,624
Legacy Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	3,289,284	3,097,929
Legacy Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	3,390,699	3,194,796
Legacy Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	550,162	559,289
Legacy Loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	970,961	854,216
Legacy Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	2,466,658	2,463,309
Legacy Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,838,841	1,783,421
Legacy Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	92,106	131,048
Legacy Loans | Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	535,711	548,840
Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	2,062,606	2,370,047
Acquired Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,321,861	1,529,182
Acquired Loans | Commercial Loans | Commercial real estate- construction
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	89,709	61,408
Acquired Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	390,241	450,012
Acquired Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	546,723	667,532
Acquired Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	293,382	348,326
Acquired Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	1,806	1,904
Acquired Loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	375,506	413,184
Acquired Loans | Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	365,239	427,681
Acquired Loans | Consumer and Other Loans | Home Equity
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	320,107	372,505
Acquired Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	24	4
Acquired Loans | Consumer and Other Loans | Other
Accounts, Notes, Loans and Financing Receivable
Total loans, net of unearned income	$ 45,108	$ 55,172

Loans - Narrative (Detail)

Loans - Narrative (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable
Deferred loan origination fees	$ 24.1	$ 22.6
Deposit liabilities reclassified as loans receivable	5.9	$ 4.2
Loans with carrying value pledged to secure public deposits and other borrowings	$ 4,500

Loans - Schedule of Aging of Lo

Loans - Schedule of Aging of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	$ 199,611	$ 306,426
Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	168,854	284,409
Residential Mortgage
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	4,666	4,627
Consumer and Other Loans
Accounts, Notes, Loans and Financing Receivable
Acquired Impaired Loans	26,091	17,390
Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	1,584,250	1,841,465
Accruing	10,150	4,249
Non-accrual Loans	14,208	6,958
Discount/Premium	(10,629)	(12,811)
Acquired Impaired Loans	464,627	530,186
Total Loans	2,062,606	2,370,047
Acquired Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total Loans	1,321,861	1,529,182
Acquired Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	53,564	26,714
Accruing	216	0
Non-accrual Loans	1,118	1,946
Discount/Premium	(183)	(243)
Acquired Impaired Loans	34,994	32,991
Total Loans	89,709	61,408
Acquired Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	284,841	326,761
Accruing	0	548
Non-accrual Loans	3,684	166
Discount/Premium	(2,670)	(3,084)
Acquired Impaired Loans	104,386	125,621
Total Loans	390,241	450,012
Acquired Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	441,193	544,731
Accruing	2,386	255
Non-accrual Loans	4,035	1,055
Discount/Premium	(94)	(565)
Acquired Impaired Loans	99,203	122,056
Total Loans	546,723	667,532
Acquired Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	256,584	314,990
Accruing	4,698	124
Non-accrual Loans	1,382	1,317
Discount/Premium	(712)	(837)
Acquired Impaired Loans	31,430	32,732
Total Loans	293,382	348,326
Acquired Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	1,657	1,910
Accruing	154	0
Non-accrual Loans	0	0
Discount/Premium	(5)	(6)
Acquired Impaired Loans	0	0
Total Loans	1,806	1,904
Acquired Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	378,204	424,300
Current or Less Than 30 days past due	263,658	290,031
Accruing	609	1,317
Non-accrual Loans	1,598	719
Discount/Premium	(1,609)	(1,835)
Acquired Impaired Loans	111,250	122,952
Total Loans	375,506	413,184
Acquired Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	322,658	377,021
Current or Less Than 30 days past due	242,091	286,411
Accruing	1,686	1,517
Non-accrual Loans	1,947	1,395
Discount/Premium	(4,497)	(5,237)
Acquired Impaired Loans	78,880	88,419
Total Loans	320,107	372,505
Acquired Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	24	12
Current or Less Than 30 days past due	18	0
Accruing	0	0
Non-accrual Loans	0	0
Discount/Premium	0	0
Acquired Impaired Loans	6	4
Total Loans	24	4
Acquired Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	0	468
Accruing	0	0
Non-accrual Loans	0	0
Discount/Premium	0	0
Acquired Impaired Loans	501	0
Total Loans	501	468
Acquired Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Current or Less Than 30 days past due	40,644	49,449
Accruing	401	488
Non-accrual Loans	444	360
Discount/Premium	(859)	(1,004)
Acquired Impaired Loans	3,977	5,411
Total Loans	44,607	54,704
Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	13,288,170	12,447,375
Accruing	41,492	26,006
Non-accrual Loans	163,748	221,543
Total Loans	13,493,410	12,694,924
Legacy Loans | Commercial Loans
Accounts, Notes, Loans and Financing Receivable
Total Loans	10,055,791	9,377,399
Legacy Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	1,008,834	740,761
Accruing	214	0
Non-accrual Loans	1,431	0
Total Loans	1,010,479	740,761
Legacy Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	1,804,289	1,775,695
Accruing	2,063	1,086
Non-accrual Loans	8,815	7,843
Total Loans	1,815,167	1,784,624
Legacy Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	3,277,719	3,088,207
Accruing	6,558	1,126
Non-accrual Loans	5,007	8,596
Total Loans	3,289,284	3,097,929
Legacy Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	3,349,442	3,158,700
Accruing	12,062	4,869
Non-accrual Loans	29,195	31,227
Total Loans	3,390,699	3,194,796
Legacy Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	453,357	407,434
Accruing	2,240	1,526
Non-accrual Loans	94,565	150,329
Total Loans	550,162	559,289
Legacy Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	955,343	836,509
Accruing	3,936	4,693
Non-accrual Loans	11,682	13,014
Total Loans	970,961	854,216
Legacy Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	1,819,163	1,768,763
Accruing	9,144	6,679
Non-accrual Loans	10,534	7,979
Total Loans	1,838,841	1,783,421
Legacy Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	89,590	127,054
Accruing	1,614	2,956
Non-accrual Loans	902	1,038
Total Loans	92,106	131,048
Legacy Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	85,690	81,602
Accruing	285	298
Non-accrual Loans	612	624
Total Loans	86,587	82,524
Legacy Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Current or less than 30 days past due	444,743	462,650
Accruing	3,376	2,773
Non-accrual Loans	1,005	893
Total Loans	449,124	466,316
30-59 days | Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	3,212	2,586
30-59 days | Acquired Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Accruing	216	0
30-59 days | Acquired Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	0	493
30-59 days | Acquired Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	2,067	223
30-59 days | Acquired Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	47	73
30-59 days | Acquired Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Accruing	154	0
30-59 days | Acquired Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	14	328
30-59 days | Acquired Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Accruing	407	1,078
30-59 days | Acquired Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
30-59 days | Acquired Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
30-59 days | Acquired Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Accruing	307	391
30-59 days | Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	27,921	18,026
30-59 days | Legacy Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Accruing	214	0
30-59 days | Legacy Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	343	959
30-59 days | Legacy Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	3,245	902
30-59 days | Legacy Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	10,633	3,999
30-59 days | Legacy Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Accruing	2,240	0
30-59 days | Legacy Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	1,933	2,012
30-59 days | Legacy Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Accruing	4,983	5,249
30-59 days | Legacy Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	1,353	2,551
30-59 days | Legacy Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Accruing	168	199
30-59 days | Legacy Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Accruing	2,809	2,155
60-89 days | Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	6,746	1,381
60-89 days | Acquired Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
60-89 days | Acquired Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	0	55
60-89 days | Acquired Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	319	0
60-89 days | Acquired Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	4,651	51
60-89 days | Acquired Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
60-89 days | Acquired Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	403	989
60-89 days | Acquired Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Accruing	1,279	189
60-89 days | Acquired Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
60-89 days | Acquired Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
60-89 days | Acquired Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Accruing	94	97
60-89 days | Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	12,961	6,876
60-89 days | Legacy Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
60-89 days | Legacy Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	1,687	127
60-89 days | Legacy Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	3,046	224
60-89 days | Legacy Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	1,429	870
60-89 days | Legacy Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Accruing	0	1,526
60-89 days | Legacy Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	1,693	1,577
60-89 days | Legacy Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Accruing	4,161	1,430
60-89 days | Legacy Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	261	405
60-89 days | Legacy Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Accruing	117	99
60-89 days | Legacy Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Accruing	567	618
Greater than 90 days | Acquired Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	192	282
Greater than 90 days | Acquired Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Acquired Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Acquired Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	0	32
Greater than 90 days | Acquired Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Acquired Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Acquired Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	192	0
Greater than 90 days | Acquired Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Accruing	0	250
Greater than 90 days | Acquired Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Acquired Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Acquired Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Legacy Loans
Accounts, Notes, Loans and Financing Receivable
Accruing	610	1,104
Greater than 90 days | Legacy Loans | Commercial Loans | Commercial real estate - construction
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Legacy Loans | Commercial Loans | Commercial real estate- owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	33	0
Greater than 90 days | Legacy Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Accounts, Notes, Loans and Financing Receivable
Accruing	267	0
Greater than 90 days | Legacy Loans | Commercial Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Legacy Loans | Commercial Loans | Energy-related
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Legacy Loans | Residential Mortgage | Residential mortgage
Accounts, Notes, Loans and Financing Receivable
Accruing	310	1,104
Greater than 90 days | Legacy Loans | Consumer and Other Loans | Consumer - home equity
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Legacy Loans | Consumer and Other Loans | Consumer - indirect automobile
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Legacy Loans | Consumer and Other Loans | Consumer - credit card
Accounts, Notes, Loans and Financing Receivable
Accruing	0	0
Greater than 90 days | Legacy Loans | Consumer and Other Loans | Consumer - other
Accounts, Notes, Loans and Financing Receivable
Accruing	$ 0	$ 0

Loans - Summary of Changes in A

Loans - Summary of Changes in Accretable Yields of Acquired Loans (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Receivables [Abstract]
Balance at beginning of period	$ 175,054	$ 227,502
Transfers from non-accretable difference to accretable yield	2,544	4,425
Accretion	(28,496)	(36,256)
Changes in expected cash flows not affecting non-accretable differences	2,439	8,949
Balance at end of period	$ 151,541	$ 204,620

Loans - Schedule of Modified TD

Loans - Schedule of Modified TDRs (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)SecurityLoan	Jun. 30, 2016USD ($)SecurityLoan	Jun. 30, 2017USD ($)SecurityLoan	Jun. 30, 2016USD ($)SecurityLoan
Financing Receivable, Modifications
Post-modification outstanding recorded investment	$ 17,892	$ 135,524	$ 28,398	$ 165,283
Troubled Debt Restructurings
Financing Receivable, Modifications
Total TDRs	28,400	165,300
TDRs in accrual status	22,800	126,600
TDRs in non-accrual status	$ 5,600	$ 38,700
TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	124	151	206	236
Pre-modification outstanding recorded investment	$ 18,453	$ 119,083	$ 29,206	$ 157,121
Post-modification outstanding recorded investment	$ 17,892	$ 135,524	$ 28,398	$ 165,283
Commercial Loans | Commercial real estate- construction | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	1	0	1	1
Pre-modification outstanding recorded investment	$ 275	$ 0	$ 275	$ 28
Post-modification outstanding recorded investment	$ 275	$ 0	$ 275	$ 26
Commercial Loans | Commercial real estate- owner-occupied | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	1	3	2	5
Pre-modification outstanding recorded investment	$ 32	$ 794	$ 1,730	$ 1,069
Post-modification outstanding recorded investment	$ 31	$ 785	$ 1,698	$ 1,050
Commercial Loans | Commercial real estate- non-owner-occupied | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	6	6	11	10
Pre-modification outstanding recorded investment	$ 2,721	$ 10,777	$ 4,409	$ 11,516
Post-modification outstanding recorded investment	$ 2,795	$ 10,047	$ 4,465	$ 10,749
Commercial Loans | Commercial and industrial | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	24	16	33	28
Pre-modification outstanding recorded investment	$ 9,028	$ 19,496	$ 9,254	$ 24,018
Post-modification outstanding recorded investment	$ 8,551	$ 19,353	$ 8,747	$ 23,632
Commercial Loans | Energy-related | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	0	19	0	25
Pre-modification outstanding recorded investment	$ 0	$ 82,882	$ 0	$ 110,443
Post-modification outstanding recorded investment	$ 0	$ 100,205	$ 0	$ 119,890
Residential Mortgage | Residential mortgage | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	6	10	10	25
Pre-modification outstanding recorded investment	$ 521	$ 1,438	$ 780	$ 4,733
Post-modification outstanding recorded investment	$ 492	$ 1,438	$ 730	$ 4,692
Consumer and Other Loans | Home Equity | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	33	36	66	57
Pre-modification outstanding recorded investment	$ 4,820	$ 2,750	$ 10,851	$ 3,928
Post-modification outstanding recorded investment	$ 4,807	$ 2,750	$ 10,771	$ 3,916
Consumer and Other Loans | Consumer - indirect automobile | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	23	0	33	0
Pre-modification outstanding recorded investment	$ 224	$ 0	$ 360	$ 0
Post-modification outstanding recorded investment	$ 114	$ 0	$ 222	$ 0
Consumer and Other Loans | Consumer - other | TDRs Occurring during the Period | Non-Covered TDRs
Financing Receivable, Modifications
Number of loans | SecurityLoan	30	61	50	85
Pre-modification outstanding recorded investment	$ 832	$ 946	$ 1,547	$ 1,386
Post-modification outstanding recorded investment	827	946	1,490	1,328
Extended maturities
Financing Receivable, Modifications
Post-modification outstanding recorded investment	8,488	54,758	15,014	57,533
Maturity and interest rate adjustment
Financing Receivable, Modifications
Post-modification outstanding recorded investment	3,886	30,781	6,502	31,048
Movement to or extension of interest-rate only payments
Financing Receivable, Modifications
Post-modification outstanding recorded investment	38	440	138	440
Interest rate adjustment
Financing Receivable, Modifications
Post-modification outstanding recorded investment	26	134	26	134
Forbearance
Financing Receivable, Modifications
Post-modification outstanding recorded investment	3,466	33,426	4,687	38,367
Other concession(s) (1)
Financing Receivable, Modifications
Post-modification outstanding recorded investment	$ 1,988	$ 15,985	$ 2,031	$ 37,761

Loans - Schedule of Subsequentl

Loans - Schedule of Subsequently Defaulted TDRs (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)SecurityLoan	Jun. 30, 2016USD ($)SecurityLoan	Jun. 30, 2017USD ($)SecurityLoan	Jun. 30, 2016USD ($)SecurityLoan
Accounts, Notes, Loans and Financing Receivable
Post-modification outstanding recorded investment	$ 17,892	$ 135,524	$ 28,398	$ 165,283
Threshold period for loans in default (in days)	30 days
Non-Covered TDRs | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	124	151	206	236
Pre-modification outstanding recorded investment	$ 18,453	$ 119,083	$ 29,206	$ 157,121
Post-modification outstanding recorded investment	$ 17,892	$ 135,524	$ 28,398	$ 165,283
Number of loans | SecurityLoan	81	65	168	115
Recorded investment	$ 18,671	$ 6,440	$ 22,744	$ 9,642
Non-Covered TDRs | Commercial Loans | Commercial real estate- construction | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	1	0	1	1
Pre-modification outstanding recorded investment	$ 275	$ 0	$ 275	$ 28
Post-modification outstanding recorded investment	$ 275	$ 0	$ 275	$ 26
Number of loans | SecurityLoan	0	0	2	0
Recorded investment	$ 0	$ 0	$ 132	$ 0
Non-Covered TDRs | Commercial Loans | Commercial real estate- owner-occupied | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	1	3	2	5
Pre-modification outstanding recorded investment	$ 32	$ 794	$ 1,730	$ 1,069
Post-modification outstanding recorded investment	$ 31	$ 785	$ 1,698	$ 1,050
Number of loans | SecurityLoan	5	0	7	0
Recorded investment	$ 2,297	$ 0	$ 2,404	$ 0
Non-Covered TDRs | Commercial Loans | Commercial real estate- non-owner-occupied | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	6	6	11	10
Pre-modification outstanding recorded investment	$ 2,721	$ 10,777	$ 4,409	$ 11,516
Post-modification outstanding recorded investment	$ 2,795	$ 10,047	$ 4,465	$ 10,749
Number of loans | SecurityLoan	9	4	14	8
Recorded investment	$ 5,640	$ 1,358	$ 6,406	$ 1,377
Non-Covered TDRs | Commercial Loans | Commercial and industrial | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	24	16	33	28
Pre-modification outstanding recorded investment	$ 9,028	$ 19,496	$ 9,254	$ 24,018
Post-modification outstanding recorded investment	$ 8,551	$ 19,353	$ 8,747	$ 23,632
Number of loans | SecurityLoan	17	5	25	8
Recorded investment	$ 8,081	$ 758	$ 8,239	$ 3,273
Non-Covered TDRs | Commercial Loans | Energy-related | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	0	19	0	25
Pre-modification outstanding recorded investment	$ 0	$ 82,882	$ 0	$ 110,443
Post-modification outstanding recorded investment	$ 0	$ 100,205	$ 0	$ 119,890
Number of loans | SecurityLoan	0	1	0	1
Recorded investment	$ 0	$ 2,250	$ 0	$ 2,250
Non-Covered TDRs | Residential Mortgage | Residential mortgage | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	6	10	10	25
Pre-modification outstanding recorded investment	$ 521	$ 1,438	$ 780	$ 4,733
Post-modification outstanding recorded investment	$ 492	$ 1,438	$ 730	$ 4,692
Number of loans | SecurityLoan	5	4	21	7
Recorded investment	$ 454	$ 480	$ 1,854	$ 536
Non-Covered TDRs | Consumer and Other Loans | Consumer - home equity | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	33	36	66	57
Pre-modification outstanding recorded investment	$ 4,820	$ 2,750	$ 10,851	$ 3,928
Post-modification outstanding recorded investment	$ 4,807	$ 2,750	$ 10,771	$ 3,916
Number of loans | SecurityLoan	19	17	37	24
Recorded investment	$ 1,532	$ 1,112	$ 2,488	$ 1,608
Non-Covered TDRs | Consumer and Other Loans | Consumer - Indirect Automobile | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	23	0	33	0
Pre-modification outstanding recorded investment	$ 224	$ 0	$ 360	$ 0
Post-modification outstanding recorded investment	$ 114	$ 0	$ 222	$ 0
Number of loans | SecurityLoan	9	0	33	0
Recorded investment	$ 75	$ 0	$ 328	$ 0
Non-Covered TDRs | Consumer and Other Loans | Consumer - other | TDRs Occurring during the Period
Accounts, Notes, Loans and Financing Receivable
Number of loans | SecurityLoan	30	61	50	85
Pre-modification outstanding recorded investment	$ 832	$ 946	$ 1,547	$ 1,386
Post-modification outstanding recorded investment	$ 827	$ 946	$ 1,490	$ 1,328
Number of loans | SecurityLoan	17	34	29	67
Recorded investment	$ 592	$ 482	$ 893	$ 598

Allowance for Credit Losses a51

Allowance for Credit Losses and Credit Quality - Schedule of Allowance for Loan Losses for Covered and Non-Covered Loan Portfolios (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Allowance for credit losses
Allowance for loan losses at beginning of period	$ 144,719	$ 138,378
Provision for loan losses before benefit attributable to FDIC loss share agreements		25,974
Adjustment attributable to FDIC loss share arrangements		(797)
Net provision for loan losses	18,204	26,771
Transfer of balance to OREO and other	258	(967)
Loans charged-off	(19,480)	(18,555)
Recoveries	2,524	2,622
Allowance for loan losses at end of period	146,225	147,452
Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	11,241	14,145
Provision for (Reversal of) unfunded lending commitments	(779)	(319)
Reserve for unfunded commitments at end of period	10,462	13,826
Allowance for credit losses at end of period	156,687	161,278
Legacy Loans
Allowance for credit losses
Allowance for loan losses at beginning of period	105,569	93,808
Provision for loan losses before benefit attributable to FDIC loss share agreements		28,390
Adjustment attributable to FDIC loss share arrangements		0
Net provision for loan losses	18,315	28,390
Transfer of balance to OREO and other	0	0
Loans charged-off	(18,098)	(17,359)
Recoveries	1,824	2,022
Allowance for loan losses at end of period	107,610	106,861
Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	11,241	14,145
Provision for (Reversal of) unfunded lending commitments	(779)	(319)
Reserve for unfunded commitments at end of period	10,462	13,826
Allowance for credit losses at end of period	118,072	120,687
Acquired Loans
Allowance for credit losses
Allowance for loan losses at beginning of period	39,150	44,570
Provision for loan losses before benefit attributable to FDIC loss share agreements		(2,416)
Adjustment attributable to FDIC loss share arrangements		(797)
Net provision for loan losses	(111)	(1,619)
Transfer of balance to OREO and other	258	(967)
Loans charged-off	(1,382)	(1,196)
Recoveries	700	600
Allowance for loan losses at end of period	38,615	40,591
Reserve For Unfunded Commitments
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
Allowance for credit losses at end of period	$ 38,615	$ 40,591

Allowance for Credit Losses a52

Allowance for Credit Losses and Credit Quality - Schedule of Allowance for Loan Losses for Legacy and Acquired Loans, by Loan Portfolio (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	$ 144,719	$ 138,378
Transfer of balance to OREO and other	258	(967)
Loans charged-off	(19,480)	(18,555)
Recoveries	2,524	2,622
Allowance for loan losses at end of period	146,225	147,452
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	11,241	14,145
Reserve for unfunded commitments at end of period	10,462	13,826
Legacy Loans
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	105,569	93,808
Provision for (Reversal of) loan losses	18,315	28,390
Transfer of balance to OREO and other	0	0
Loans charged-off	(18,098)	(17,359)
Recoveries	1,824	2,022
Allowance for loan losses at end of period	107,610	106,861
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	11,241	14,145
Provision for (Reversal of) unfunded commitments	(779)	(319)
Reserve for unfunded commitments at end of period	10,462	13,826
Allowance on loans individually evaluated for impairment	26,920	14,485
Allowance on loans collectively evaluated for impairment	80,690	92,376
Loans, net of unearned income:
Loans, net of unearned income	13,493,410	11,984,849
Balance at end of period individually evaluated for impairment	199,468	221,358
Balance at end of period collectively evaluated for impairment	13,293,942	11,763,491
Legacy Loans | Commercial Loans | Real Estate
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	25,408	24,658
Provision for (Reversal of) loan losses	4,323	(715)
Loans charged-off	(256)	(1,549)
Recoveries	189	644
Allowance for loan losses at end of period	29,664	23,038
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	3,206	4,160
Provision for (Reversal of) unfunded commitments	294	(26)
Reserve for unfunded commitments at end of period	3,500	4,134
Allowance on loans individually evaluated for impairment	1,316	691
Allowance on loans collectively evaluated for impairment	28,348	22,347
Loans, net of unearned income:
Loans, net of unearned income	6,114,930	5,097,689
Balance at end of period individually evaluated for impairment	42,204	26,152
Balance at end of period collectively evaluated for impairment	6,072,726	5,071,537
Legacy Loans | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	35,434	23,283
Provision for (Reversal of) loan losses	5,181	5,874
Loans charged-off	(8,366)	(1,154)
Recoveries	269	35
Allowance for loan losses at end of period	32,518	28,038
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	3,535	3,448
Provision for (Reversal of) unfunded commitments	(46)	(60)
Reserve for unfunded commitments at end of period	3,489	3,388
Allowance on loans individually evaluated for impairment	7,192	969
Allowance on loans collectively evaluated for impairment	25,326	27,069
Loans, net of unearned income:
Loans, net of unearned income	3,390,699	3,027,590
Balance at end of period individually evaluated for impairment	36,836	34,298
Balance at end of period collectively evaluated for impairment	3,353,863	2,993,292
Legacy Loans | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	22,486	23,863
Provision for (Reversal of) loan losses	3,387	16,819
Loans charged-off	(2,845)	(7,715)
Recoveries	0	0
Allowance for loan losses at end of period	23,028	32,967
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	1,003	2,665
Provision for (Reversal of) unfunded commitments	(856)	(442)
Reserve for unfunded commitments at end of period	147	2,223
Allowance on loans individually evaluated for impairment	16,094	11,925
Allowance on loans collectively evaluated for impairment	6,934	21,042
Loans, net of unearned income:
Loans, net of unearned income	550,162	659,510
Balance at end of period individually evaluated for impairment	89,814	148,317
Balance at end of period collectively evaluated for impairment	460,348	511,193
Legacy Loans | Residential Mortgage
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	3,835	3,947
Provision for (Reversal of) loan losses	(884)	264
Loans charged-off	(45)	(173)
Recoveries	77	27
Allowance for loan losses at end of period	2,983	4,065
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	657	830
Provision for (Reversal of) unfunded commitments	(89)	(23)
Reserve for unfunded commitments at end of period	568	807
Allowance on loans individually evaluated for impairment	137	100
Allowance on loans collectively evaluated for impairment	2,846	3,965
Loans, net of unearned income:
Loans, net of unearned income	970,961	794,701
Balance at end of period individually evaluated for impairment	4,631	3,451
Balance at end of period collectively evaluated for impairment	966,330	791,250
Legacy Loans | Consumer and Other Loans
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	18,406	18,057
Provision for (Reversal of) loan losses	6,308	6,148
Loans charged-off	(6,586)	(6,768)
Recoveries	1,289	1,316
Allowance for loan losses at end of period	19,417	18,753
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	2,840	3,042
Provision for (Reversal of) unfunded commitments	(82)	232
Reserve for unfunded commitments at end of period	2,758	3,274
Allowance on loans individually evaluated for impairment	2,181	800
Allowance on loans collectively evaluated for impairment	17,236	17,953
Loans, net of unearned income:
Loans, net of unearned income	2,466,658	2,405,359
Balance at end of period individually evaluated for impairment	25,983	9,140
Balance at end of period collectively evaluated for impairment	2,440,675	2,396,219
Acquired Loans
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	39,150	44,570
Provision for (Reversal of) loan losses	(111)	(1,619)
Increase (Decrease) in FDIC loss share receivable		(797)
Transfer of balance to OREO and other	258	(967)
Loans charged-off	(1,382)	(1,196)
Recoveries	700	600
Allowance for loan losses at end of period	38,615	40,591
Financing Receivable, Reserve For Unfunded Commitments
Reserve for unfunded commitments at beginning of period	0	0
Reserve for unfunded commitments at end of period	0	0
Allowance on loans individually evaluated for impairment	1,204	68
Allowance on loans collectively evaluated for impairment	37,411	40,523
Loans, net of unearned income:
Loans, net of unearned income	2,062,606	2,737,712
Balance at end of period individually evaluated for impairment	16,592	7,877
Balance at end of period collectively evaluated for impairment	1,581,387	2,117,503
Acquired Loans | Commercial Loans | Real Estate
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	23,574	25,979
Provision for (Reversal of) loan losses	1,407	(1,804)
Increase (Decrease) in FDIC loss share receivable		45
Transfer of balance to OREO and other	135	(880)
Loans charged-off	(1,026)	(31)
Recoveries	145	85
Allowance for loan losses at end of period	24,235	23,394
Financing Receivable, Reserve For Unfunded Commitments
Allowance on loans individually evaluated for impairment	402	0
Allowance on loans collectively evaluated for impairment	23,833	23,394
Loans, net of unearned income:
Loans, net of unearned income	1,026,673	1,374,312
Balance at end of period individually evaluated for impairment	10,225	1,145
Balance at end of period collectively evaluated for impairment	777,865	1,038,737
Acquired Loans | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	3,230	2,819
Provision for (Reversal of) loan losses	(46)	350
Increase (Decrease) in FDIC loss share receivable		(28)
Transfer of balance to OREO and other	(69)	323
Loans charged-off	(71)	(700)
Recoveries	77	112
Allowance for loan losses at end of period	3,121	2,876
Financing Receivable, Reserve For Unfunded Commitments
Allowance on loans individually evaluated for impairment	678	22
Allowance on loans collectively evaluated for impairment	2,443	2,854
Loans, net of unearned income:
Loans, net of unearned income	293,382	408,219
Balance at end of period individually evaluated for impairment	2,851	2,075
Balance at end of period collectively evaluated for impairment	259,101	368,283
Acquired Loans | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	39	125
Provision for (Reversal of) loan losses	(21)	(52)
Increase (Decrease) in FDIC loss share receivable		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	18	73
Financing Receivable, Reserve For Unfunded Commitments
Allowance on loans individually evaluated for impairment	0	0
Allowance on loans collectively evaluated for impairment	18	73
Loans, net of unearned income:
Loans, net of unearned income	1,806	2,524
Balance at end of period individually evaluated for impairment	0	0
Balance at end of period collectively evaluated for impairment	1,806	2,524
Acquired Loans | Residential Mortgage
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	7,412	7,841
Provision for (Reversal of) loan losses	(578)	896
Increase (Decrease) in FDIC loss share receivable		(562)
Transfer of balance to OREO and other	2	22
Loans charged-off	(30)	0
Recoveries	65	29
Allowance for loan losses at end of period	6,871	8,226
Financing Receivable, Reserve For Unfunded Commitments
Allowance on loans individually evaluated for impairment	32	2
Allowance on loans collectively evaluated for impairment	6,839	8,224
Loans, net of unearned income:
Loans, net of unearned income	375,506	454,361
Balance at end of period individually evaluated for impairment	660	245
Balance at end of period collectively evaluated for impairment	263,596	321,879
Acquired Loans | Consumer and Other Loans
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses at beginning of period	4,895	7,806
Provision for (Reversal of) loan losses	(873)	(1,009)
Increase (Decrease) in FDIC loss share receivable		(252)
Transfer of balance to OREO and other	190	(432)
Loans charged-off	(255)	(465)
Recoveries	413	374
Allowance for loan losses at end of period	4,370	6,022
Financing Receivable, Reserve For Unfunded Commitments
Allowance on loans individually evaluated for impairment	92	44
Allowance on loans collectively evaluated for impairment	4,278	5,978
Loans, net of unearned income:
Loans, net of unearned income	365,239	498,296
Balance at end of period individually evaluated for impairment	2,856	4,412
Balance at end of period collectively evaluated for impairment	279,019	386,080
Receivables Acquired with Deteriorated Credit Quality | Acquired Loans
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	464,627	612,332
Receivables Acquired with Deteriorated Credit Quality | Acquired Loans | Commercial Loans | Real Estate
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	238,583	334,430
Receivables Acquired with Deteriorated Credit Quality | Acquired Loans | Commercial Loans | Commercial and industrial
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	31,430	37,861
Receivables Acquired with Deteriorated Credit Quality | Acquired Loans | Commercial Loans | Energy-related
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	0	0
Receivables Acquired with Deteriorated Credit Quality | Acquired Loans | Residential Mortgage
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	111,250	132,237
Receivables Acquired with Deteriorated Credit Quality | Acquired Loans | Consumer and Other Loans
Loans, net of unearned income:
Balance at end of period acquired with deteriorated credit quality	$ 83,364	$ 107,804

Allowance for Credit Losses a53

Allowance for Credit Losses and Credit Quality - Investment in Legacy and Acquired Loans by Credit Quality Indicator (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	$ 24,100	$ 22,600
Acquired Loans
Financing Receivable, Allowance for Credit Losses
Total Loans	2,062,606	2,370,047
Acquired Loans | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(24,244)	(38,153)
Total Loans	1,321,861	1,529,182
Acquired Loans | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	13,899	8,759
Total Loans	89,709	61,408
Acquired Loans | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(12,072)	(3,084)
Total Loans	390,241	450,012
Acquired Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(24,742)	(39,335)
Total Loans	546,723	667,532
Acquired Loans | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(1,324)	(4,487)
Total Loans	293,382	348,326
Acquired Loans | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(5)	(6)
Total Loans	1,806	1,904
Acquired Loans | Residential and Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(44,706)	(53,753)
Current	749,054	859,474
30 or more days past due	36,397	35,144
Total Loans	740,745	840,865
Acquired Loans | Residential Mortgage | Residential mortgage
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(24,819)	(32,030)
Current	378,204	424,300
30 or more days past due	22,121	20,914
Total Loans	375,506	413,184
Acquired Loans | Consumer and Other Loans | Consumer - home equity
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(15,602)	(17,323)
Current	322,658	377,021
30 or more days past due	13,051	12,807
Total Loans	320,107	372,505
Acquired Loans | Consumer and Other Loans | Consumer - Indirect Automobile
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	0	(8)
Current	24	12
30 or more days past due	0	0
Total Loans	24	4
Acquired Loans | Consumer and Other Loans | Consumer - Credit Card
Financing Receivable, Allowance for Credit Losses
Total Loans	501	468
Acquired Loans | Consumer and Other Loans | Consumer - Other
Financing Receivable, Allowance for Credit Losses
Premium/(Discount)	(4,285)	(4,392)
Current	48,168	58,141
30 or more days past due	1,225	1,423
Total Loans	45,108	55,172
Acquired Loans | Consumer and Other Loans | Consumer - other
Financing Receivable, Allowance for Credit Losses
Total Loans	44,607	54,704
Acquired Loans | Pass | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	1,274,453	1,461,625
Acquired Loans | Pass | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	71,157	46,498
Acquired Loans | Pass | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	384,411	426,492
Acquired Loans | Pass | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	541,724	663,571
Acquired Loans | Pass | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	275,350	323,154
Acquired Loans | Pass | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	1,811	1,910
Acquired Loans | Special Mention | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	13,357	21,159
Acquired Loans | Special Mention | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	1,208	459
Acquired Loans | Special Mention | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	3,275	7,664
Acquired Loans | Special Mention | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	3,434	11,620
Acquired Loans | Special Mention | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	5,440	1,416
Acquired Loans | Special Mention | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	0	0
Acquired Loans | Substandard | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	55,561	80,003
Acquired Loans | Substandard | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	3,431	3,118
Acquired Loans | Substandard | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	14,627	17,584
Acquired Loans | Substandard | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	26,188	31,552
Acquired Loans | Substandard | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	11,315	27,749
Acquired Loans | Substandard | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	0	0
Acquired Loans | Doubtful | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	2,734	4,525
Acquired Loans | Doubtful | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	14	2,574
Acquired Loans | Doubtful | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	0	1,356
Acquired Loans | Doubtful | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	119	101
Acquired Loans | Doubtful | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	2,601	494
Acquired Loans | Doubtful | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	0	0
Acquired Loans | Loss | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross		23
Acquired Loans | Loss | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross		0
Acquired Loans | Loss | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross		0
Acquired Loans | Loss | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross		23
Acquired Loans | Loss | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross		0
Acquired Loans | Loss | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross		0
Legacy Loans
Financing Receivable, Allowance for Credit Losses
Current	13,288,170	12,447,375
Total Loans	13,493,410	12,694,924
Legacy Loans | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Total Loans	10,055,791	9,377,399
Legacy Loans | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Current	1,008,834	740,761
Total Loans	1,010,479	740,761
Legacy Loans | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Current	1,804,289	1,775,695
Total Loans	1,815,167	1,784,624
Legacy Loans | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Current	3,277,719	3,088,207
Total Loans	3,289,284	3,097,929
Legacy Loans | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Current	3,349,442	3,158,700
Total Loans	3,390,699	3,194,796
Legacy Loans | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Current	453,357	407,434
Total Loans	550,162	559,289
Legacy Loans | Residential and Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Current	3,394,529	3,276,578
30 or more days past due	43,090	40,947
Total Loans	3,437,619	3,317,525
Legacy Loans | Residential Mortgage | Residential mortgage
Financing Receivable, Allowance for Credit Losses
Current	955,343	836,509
30 or more days past due	15,618	17,707
Total Loans	970,961	854,216
Legacy Loans | Consumer and Other Loans | Consumer - home equity
Financing Receivable, Allowance for Credit Losses
Current	1,819,163	1,768,763
30 or more days past due	19,678	14,658
Total Loans	1,838,841	1,783,421
Legacy Loans | Consumer and Other Loans | Consumer - Indirect Automobile
Financing Receivable, Allowance for Credit Losses
Current	89,590	127,054
30 or more days past due	2,516	3,994
Total Loans	92,106	131,048
Legacy Loans | Consumer and Other Loans | Consumer - Credit Card
Financing Receivable, Allowance for Credit Losses
Current	85,690	81,602
30 or more days past due	897	922
Total Loans	86,587	82,524
Legacy Loans | Consumer and Other Loans | Consumer - other
Financing Receivable, Allowance for Credit Losses
Current	444,743	462,650
30 or more days past due	4,381	3,666
Total Loans	449,124	466,316
Legacy Loans | Pass | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	9,650,074	8,890,604
Legacy Loans | Pass | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	997,264	734,687
Legacy Loans | Pass | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	1,740,717	1,738,024
Legacy Loans | Pass | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	3,251,368	3,063,470
Legacy Loans | Pass | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	3,287,383	3,112,300
Legacy Loans | Pass | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	373,342	242,123
Legacy Loans | Special Mention | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	147,904	138,209
Legacy Loans | Special Mention | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	7,917	2,203
Legacy Loans | Special Mention | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	39,772	17,542
Legacy Loans | Special Mention | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	8,696	8,617
Legacy Loans | Special Mention | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	42,422	29,763
Legacy Loans | Special Mention | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	49,097	80,084
Legacy Loans | Substandard | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	201,875	319,694
Legacy Loans | Substandard | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	5,298	3,871
Legacy Loans | Substandard | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	34,210	29,058
Legacy Loans | Substandard | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	29,220	25,842
Legacy Loans | Substandard | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	58,527	35,199
Legacy Loans | Substandard | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	74,620	225,724
Legacy Loans | Doubtful | Commercial Loans
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	55,938	28,892
Legacy Loans | Doubtful | Commercial Loans | Commercial real estate - construction
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	0	0
Legacy Loans | Doubtful | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	468	0
Legacy Loans | Doubtful | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	0	0
Legacy Loans | Doubtful | Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	2,367	17,534
Legacy Loans | Doubtful | Commercial Loans | Energy-related
Financing Receivable, Allowance for Credit Losses
Loans and Leases Receivable, before Fees, Gross	$ 53,103	$ 11,358

Allowance for Credit Losses a54

Allowance for Credit Losses and Credit Quality - Schedule of Investment in Legacy Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Financing Receivable, Impaired
Acquired Impaired Loans	$ 199,611		$ 199,611		$ 306,426
Unpaid principal balance	199,468		199,468		292,645
Related allowance	(2,181)		(2,181)		(1,358)
Average Recorded Investment	205,419	$ 199,211	208,446	$ 196,439
Interest Income Recognized	1,077	1,761	2,289	3,590
Commercial Loans
Financing Receivable, Impaired
Acquired Impaired Loans	168,854		168,854		284,409
Unpaid principal balance	168,854		168,854		271,876
Related allowance	(26,920)		(26,920)		(22,776)
Average Recorded Investment	175,205	186,698	179,244	184,242
Interest Income Recognized	746	1,638	1,647	3,344
Residential Mortgage
Financing Receivable, Impaired
Acquired Impaired Loans	4,666		4,666		4,627
Unpaid principal balance	4,631		4,631		4,312
Related allowance	(24,602)		(24,602)		(21,274)
Average Recorded Investment	4,658	3,467	4,685	3,482
Interest Income Recognized	46	28	92	57
Consumer and Other Loans
Financing Receivable, Impaired
Acquired Impaired Loans	26,091		26,091		17,390
Unpaid principal balance	25,983		25,983		16,457
Related allowance	(137)		(137)		(144)
Average Recorded Investment	25,556	9,046	24,517	8,715
Interest Income Recognized	285	95	550	189
With No Related Allowance Recorded [Member] | Commercial Loans | Commercial real estate- construction
Financing Receivable, Impaired
Acquired Impaired Loans	2,123		2,123		38
Unpaid principal balance	2,123		2,123		38
Average Recorded Investment	2,123	27	2,123	30
Interest Income Recognized	13	0	39	0
With No Related Allowance Recorded [Member] | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Impaired
Acquired Impaired Loans	13,932		13,932		4,593
Unpaid principal balance	13,932		13,932		4,593
Average Recorded Investment	14,054	2,072	14,179	2,085
Interest Income Recognized	158	20	404	41
With No Related Allowance Recorded [Member] | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Impaired
Acquired Impaired Loans	4,443		4,443		12,668
Unpaid principal balance	4,443		4,443		11,876
Average Recorded Investment	4,409	13,395	4,433	13,454
Interest Income Recognized	39	123	67	237
With No Related Allowance Recorded [Member] | Commercial Loans | Commercial and industrial
Financing Receivable, Impaired
Acquired Impaired Loans	16,016		16,016		14,202
Unpaid principal balance	16,016		16,016		13,189
Average Recorded Investment	21,116	36,212	21,998	41,074
Interest Income Recognized	106	467	232	947
With No Related Allowance Recorded [Member] | Commercial Loans | Energy-related
Financing Receivable, Impaired
Acquired Impaired Loans	32,013		32,013		152,424
Unpaid principal balance	32,013		32,013		143,239
Average Recorded Investment	32,370	106,692	34,330	102,364
Interest Income Recognized	44	912	102	1,857
With No Related Allowance Recorded [Member] | Commercial Loans | Residential mortgage
Financing Receivable, Impaired
Acquired Impaired Loans	1,123		1,123		0
Unpaid principal balance	1,123		1,123		0
Average Recorded Investment	1,130	825	1,136	825
Interest Income Recognized	12	10	24	19
With No Related Allowance Recorded [Member] | Consumer and Other Loans | Consumer - home equity
Financing Receivable, Impaired
Acquired Impaired Loans	3,336		3,336		0
Unpaid principal balance	3,336		3,336		0
Average Recorded Investment	3,347	0	3,356	0
Interest Income Recognized	32	0	65	0
With No Related Allowance Recorded [Member] | Consumer and Other Loans | Consumer - other
Financing Receivable, Impaired
Acquired Impaired Loans	0		0		0
Unpaid principal balance	0		0		0
With Allowance Recorded [Member] | Commercial Loans | Commercial real estate- construction
Financing Receivable, Impaired
Acquired Impaired Loans	36		36		0
Unpaid principal balance	36		36		0
Related allowance	(1)		(1)		0
Average Recorded Investment	37	0	37	0
Interest Income Recognized	1	0	1	0
With Allowance Recorded [Member] | Commercial Loans | Commercial real estate- owner-occupied
Financing Receivable, Impaired
Acquired Impaired Loans	17,945		17,945		17,580
Unpaid principal balance	17,945		17,945		17,429
Related allowance	(690)		(690)		(640)
Average Recorded Investment	17,908	10,636	17,998	10,694
Interest Income Recognized	86	83	186	166
With Allowance Recorded [Member] | Commercial Loans | Commercial real estate- non-owner-occupied
Financing Receivable, Impaired
Acquired Impaired Loans	3,725		3,725		108
Unpaid principal balance	3,725		3,725		95
Related allowance	(625)		(625)		(1)
Average Recorded Investment	3,761	53	3,774	60
Interest Income Recognized	13	0	57	1
With Allowance Recorded [Member] | Commercial Loans | Commercial and industrial
Financing Receivable, Impaired
Acquired Impaired Loans	20,820		20,820		28,829
Unpaid principal balance	20,820		20,820		28,329
Related allowance	(7,192)		(7,192)		(10,864)
Average Recorded Investment	21,028	2,125	21,504	2,191
Interest Income Recognized	284	23	555	48
With Allowance Recorded [Member] | Commercial Loans | Energy-related
Financing Receivable, Impaired
Acquired Impaired Loans	57,801		57,801		53,967
Unpaid principal balance	57,801		57,801		53,088
Related allowance	(16,094)		(16,094)		(9,769)
Average Recorded Investment	58,399	15,486	58,868	12,290
Interest Income Recognized	2	10	4	47
With Allowance Recorded [Member] | Residential Mortgage | Residential mortgage
Financing Receivable, Impaired
Acquired Impaired Loans	3,543		3,543		4,627
Unpaid principal balance	3,508		3,508		4,312
Related allowance	(137)		(137)		(144)
Average Recorded Investment	3,528	2,642	3,549	2,657
Interest Income Recognized	34	18	68	38
With Allowance Recorded [Member] | Consumer and Other Loans | Consumer - home equity
Financing Receivable, Impaired
Acquired Impaired Loans	18,865		18,865		13,906
Unpaid principal balance	18,757		18,757		13,257
Related allowance	(1,805)		(1,805)		(993)
Average Recorded Investment	18,359	7,550	17,443	7,290
Interest Income Recognized	196	74	375	146
With Allowance Recorded [Member] | Consumer and Other Loans | Consumer - Indirect Automobile
Financing Receivable, Impaired
Acquired Impaired Loans	668		668		1,037
Unpaid principal balance	668		668		758
Related allowance	(83)		(83)		(114)
Average Recorded Investment	750	650	797	723
Interest Income Recognized	6	6	14	18
With Allowance Recorded [Member] | Consumer and Other Loans | Consumer - other
Financing Receivable, Impaired
Acquired Impaired Loans	3,222		3,222		2,447
Unpaid principal balance	3,222		3,222		2,442
Related allowance	(293)		(293)		$ (251)
Average Recorded Investment	3,100	846	2,921	702
Interest Income Recognized	$ 51	$ 15	$ 96	$ 25

Goodwill and Other Intangible55

Goodwill and Other Intangible Assets - Schedule of Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Goodwill
Balance at beginning of the period	$ 726,856	$ 724,603
Goodwill adjustments during the year		2,253
Goodwill adjustments during the year	0
Balance at end of the period	726,856	726,856
Operating Segments | IBERIABANK
Goodwill
Balance at beginning of the period	698,513	696,260
Goodwill adjustments during the year		2,253
Goodwill adjustments during the year	0
Balance at end of the period	698,513	698,513
Operating Segments | IMC
Goodwill
Balance at beginning of the period	23,178	23,178
Goodwill adjustments during the year		0
Goodwill adjustments during the year	0
Balance at end of the period	23,178	23,178
Operating Segments | LTC
Goodwill
Balance at beginning of the period	5,165	5,165
Goodwill adjustments during the year		0
Goodwill adjustments during the year	0
Balance at end of the period	$ 5,165	$ 5,165

Goodwill and Other Intangible56

Goodwill and Other Intangible Assets - Narrative (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Title plant assets	$ 6.7	$ 6.7

Goodwill and Other Intangible57

Goodwill and Other Intangible Assets - Schedule of Mortgage Servicing Rights at Carrying Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 75,207	$ 75,412
Accumulated Amortization	(56,474)	(53,251)
Net Carrying Amount	18,733	22,161
Mortgage servicing rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,265	7,202
Accumulated Amortization	(3,576)	(3,144)
Net Carrying Amount	$ 4,689	$ 4,058

Goodwill and Other Intangible58

Goodwill and Other Intangible Assets - Schedule of Definite-Lived Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 75,207	$ 75,412
Accumulated Amortization	(56,474)	(53,251)
Net Carrying Amount	18,733	22,161
Core deposit intangibles
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	74,001	74,001
Accumulated Amortization	(55,501)	(52,165)
Net Carrying Amount	18,500	21,836
Customer relationship intangible asset
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,143	1,348
Accumulated Amortization	(942)	(1,064)
Net Carrying Amount	201	284
Non-compete agreement
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	63	63
Accumulated Amortization	(31)	(22)
Net Carrying Amount	$ 32	$ 41

Derivative Instruments and Ot59

Derivative Instruments and Other Hedging Activities - Schedule of Outstanding Derivative Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value of Derivatives
Derivative Asset	$ 32,900	$ 38,886
Derivative Liability	28,684	30,209
Notional Amount of Derivatives
Derivative assets	1,715,139	1,565,509
Derivative liabilities	1,643,393	1,528,184
Designated as Hedging Instruments
Fair Value of Derivatives
Derivative Asset	0	0
Derivative Liability	1,041	525
Notional Amount of Derivatives
Derivative assets	0	0
Derivative liabilities	108,500	108,500
Designated as Hedging Instruments | Interest rate contracts
Notional Amount of Derivatives
Derivative assets	0	0
Derivative liabilities	108,500	108,500
Designated as Hedging Instruments | Interest rate contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	0	0
Designated as Hedging Instruments | Interest rate contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	1,041	525
Not Designated as Hedging Instruments
Notional Amount of Derivatives
Derivative assets	1,715,139	1,565,509
Derivative liabilities	1,534,893	1,419,684
Not Designated as Hedging Instruments | Other Assets
Fair Value of Derivatives
Derivative Asset	32,900	38,886
Not Designated as Hedging Instruments | Other Liabilities
Fair Value of Derivatives
Derivative Liability	27,643	29,684
Not Designated as Hedging Instruments | Interest rate contracts
Notional Amount of Derivatives
Derivative assets	1,120,278	1,033,955
Derivative liabilities	1,120,278	1,033,955
Not Designated as Hedging Instruments | Interest rate contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	20,432	20,719
Not Designated as Hedging Instruments | Interest rate contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	18,384	20,719
Not Designated as Hedging Instruments | Foreign exchange contracts
Notional Amount of Derivatives
Derivative assets	1,724	4,474
Derivative liabilities	1,724	4,474
Not Designated as Hedging Instruments | Foreign exchange contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	73	27
Not Designated as Hedging Instruments | Foreign exchange contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	73	26
Not Designated as Hedging Instruments | Forward sales contracts
Notional Amount of Derivatives
Derivative assets	214,925	229,181
Derivative liabilities	131,915	120,567
Not Designated as Hedging Instruments | Forward sales contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	860	6,014
Not Designated as Hedging Instruments | Forward sales contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	706	794
Not Designated as Hedging Instruments | Written and purchased options
Notional Amount of Derivatives
Derivative assets	369,582	289,115
Derivative liabilities	177,921	154,170
Not Designated as Hedging Instruments | Written and purchased options | Other Assets
Fair Value of Derivatives
Derivative Asset	11,535	12,125
Not Designated as Hedging Instruments | Written and purchased options | Other Liabilities
Fair Value of Derivatives
Derivative Liability	8,439	8,098
Not Designated as Hedging Instruments | Other contracts
Notional Amount of Derivatives
Derivative assets	8,630	8,784
Derivative liabilities	103,055	106,518
Not Designated as Hedging Instruments | Other contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	0	1
Not Designated as Hedging Instruments | Other contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	$ 41	$ 47

Derivative Instruments and Ot60

Derivative Instruments and Other Hedging Activities - Narrative (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional amount of derivative liabilities	$ 1,643,393	$ 1,528,184
Cash as collateral for derivative transactions	(1,513)	(1,892)
Cash Posted As Variation Margin for Derivatives	2,700
Not Designated as Hedging Instruments
Derivative [Line Items]
Notional amount of derivative liabilities	1,534,893	1,419,684
Not Designated as Hedging Instruments | Other contracts
Derivative [Line Items]
Notional amount of derivative liabilities	$ 103,055	$ 106,518

Derivative Instruments and Ot61

Derivative Instruments and Other Hedging Activities - Reconciliation of Gross Amounts in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivative assets
Gross derivative assets	$ 28,761	$ 28,804
Gross amounts not offset in the Balance Sheet, derivatives	(8,747)	(9,677)
Gross amounts not offset in the Balance Sheet, collateral	0	0
Net derivative assets	20,014	19,127
Derivative liabilities
Gross derivative liabilities	19,425	21,244
Gross amounts not offset in the Balance Sheet, derivatives	(8,747)	(9,677)
Gross amounts not offset in the Balance Sheet, collateral	(1,513)	(1,892)
Net derivative liabilities	9,165	9,675
Written and purchased options
Derivative assets
Gross derivative assets	8,329	8,085
Gross amounts not offset in the Balance Sheet, derivatives	0	0
Gross amounts not offset in the Balance Sheet, collateral	0	0
Net derivative assets	8,329	8,085
Designated as Hedging Instruments | Interest rate contracts
Derivative assets
Gross derivative assets	20,432
Gross amounts not offset in the Balance Sheet, derivatives	(8,747)
Gross amounts not offset in the Balance Sheet, collateral	0
Net derivative assets	11,685
Derivative liabilities
Gross derivative liabilities	1,041	525
Gross amounts not offset in the Balance Sheet, derivatives	0	0
Gross amounts not offset in the Balance Sheet, collateral	0	(181)
Net derivative liabilities	1,041	344
Not Designated as Hedging Instruments | Interest rate contracts
Derivative assets
Gross derivative assets		20,719
Gross amounts not offset in the Balance Sheet, derivatives		(9,677)
Gross amounts not offset in the Balance Sheet, collateral		0
Net derivative assets		11,042
Derivative liabilities
Gross derivative liabilities	18,384	20,719
Gross amounts not offset in the Balance Sheet, derivatives	(8,747)	(9,677)
Gross amounts not offset in the Balance Sheet, collateral	(1,513)	(1,711)
Net derivative liabilities	$ 8,124	$ 9,331

Derivative Instruments and Ot62

Derivative Instruments and Other Hedging Activities - Effect of Hedging Instruments on Consolidated Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Designated as Hedging Instruments | Cash Flow Hedging | Interest rate contracts | Other income (expense)
Derivative Instruments and Hedging Activities Disclosures
Amount of Gain (Loss) Recognized in OCI net of taxes (Effective Portion)	$ (790)	$ (2,328)	$ (627)	$ (6,455)
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income net of taxes (Effective Portion)	(103)	0	(148)	0
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	0	0	0	0
Not Designated as Hedging Instruments
Derivative Instruments and Hedging Activities Disclosures
Amount of Gain (Loss) Recognized in Income on Derivatives	(1,801)	35	(378)	1,637
Not Designated as Hedging Instruments | Interest rate contracts | Other income
Derivative Instruments and Hedging Activities Disclosures
Amount of Gain (Loss) Recognized in Income on Derivatives	1,299	2,332	2,416	5,294
Not Designated as Hedging Instruments | Foreign exchange contracts | Other income
Derivative Instruments and Hedging Activities Disclosures
Amount of Gain (Loss) Recognized in Income on Derivatives	7	2	14	3
Not Designated as Hedging Instruments | Forward sales contracts | Mortgage income
Derivative Instruments and Hedging Activities Disclosures
Amount of Gain (Loss) Recognized in Income on Derivatives	(1,526)	(4,787)	(1,886)	(10,130)
Not Designated as Hedging Instruments | Written and purchased options | Mortgage income
Derivative Instruments and Hedging Activities Disclosures
Amount of Gain (Loss) Recognized in Income on Derivatives	(1,586)	2,488	(931)	6,470
Not Designated as Hedging Instruments | Other contracts | Other income
Derivative Instruments and Hedging Activities Disclosures
Amount of Gain (Loss) Recognized in Income on Derivatives	$ 5	$ 0	$ 9	$ 0

Shareholders' Equity, Capital63

Shareholders' Equity, Capital Ratios and Other Regulatory Matters - Shareholders' Equity (Details) $ / shares in Units, $ in Thousands	Mar. 07, 2017USD ($)$ / sharesshares	May 09, 2016USD ($)	Aug. 05, 2015USD ($)	Jun. 30, 2017USD ($)$ / sharesshares	Jun. 30, 2016USD ($)shares	Dec. 31, 2016USD ($)$ / shares
Class of Stock [Line Items]
Preferred stock, par value (in usd per share) | $ / shares				$ 1		$ 1
Liquidation preference (per share) | $ / shares				$ 10,000		$ 10,000
Liquidation preference value				$ 137,500
Carrying Amount				$ 132,097		$ 132,097
Number of shares authorized to be repurchased | shares					950,000
Shares authorized to be repurchased | shares				747,494
Proceeds from common stock issued				$ 485,194	$ 0
Series B Depositary Shares
Class of Stock [Line Items]
Depository shares to preferred stock ratio			0.0025
Series B Preferred Stock
Class of Stock [Line Items]
Ownership per share			6.625%
Liquidation preference value			$ 80,000
Carrying Amount				76,812		76,812
Series C Depository Shares
Class of Stock [Line Items]
Depository shares to preferred stock ratio		0.0025
Series C Preferred Stock
Class of Stock [Line Items]
Ownership per share		6.60%
Liquidation preference value		$ 57,500
Carrying Amount				$ 55,285		$ 55,285
Common Stock
Class of Stock [Line Items]
Common stock issued (in shares) | shares	6,100,000
Price per share of stock of issued | $ / shares	$ 83
Proceeds from common stock issued	$ 485,200

Shareholders' Equity, Capital64

Shareholders' Equity, Capital Ratios and Other Regulatory Matters - Actual Capital Amounts and Ratios (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Consolidated
Tier 1 Leverage
Minimum amount	$ 845,167	$ 818,440
Minimum ratio	4.00%	4.00%
Actual amount	$ 2,787,729	$ 2,221,528
Actual ratio	13.19%	10.86%
Common Equity Tier 1 (CET1)
Minimum amount	$ 822,980	$ 794,334
Minimum ratio	4.50%	4.50%
Actual amount	$ 2,655,632	$ 2,089,431
Actual ratio	14.52%	11.84%
Tier 1 Risk-Based Capital (1)
Minimum amount	$ 1,097,306	$ 1,059,112
Minimum ratio	6.00%	6.00%
Actual amount	$ 2,787,729	$ 2,221,528
Actual ratio	15.24%	12.59%
Total Risk-Based Capital (1)
Minimum amount	$ 1,463,075	$ 1,412,149
Minimum ratio	8.00%	8.00%
Actual amount	$ 3,060,916	$ 2,493,988
Actual ratio	16.74%	14.13%
IBERIABANK
Tier 1 Leverage
Minimum amount	$ 842,313	$ 816,152
Minimum ratio	4.00%	4.00%
Well capitalized amount	$ 1,052,892	$ 1,020,190
Well capitalized ratio	5.00%	5.00%
Actual amount	$ 1,994,073	$ 1,878,703
Actual ratio	9.47%	9.21%
Common Equity Tier 1 (CET1)
Minimum amount	$ 820,978	$ 792,111
Minimum ratio	4.50%	4.50%
Well capitalized amount	$ 1,185,857	$ 1,144,160
Well capitalized ratio	6.50%	6.50%
Actual amount	$ 1,994,073	$ 1,878,703
Actual ratio	10.93%	10.67%
Tier 1 Risk-Based Capital (1)
Minimum amount	$ 1,094,637	$ 1,056,147
Minimum ratio	6.00%	6.00%
Well capitalized amount	$ 1,459,516	$ 1,408,197
Well capitalized ratio	8.00%	8.00%
Actual amount	$ 1,994,073	$ 1,878,703
Actual ratio	10.93%	10.67%
Total Risk-Based Capital (1)
Minimum amount	$ 1,459,516	$ 1,408,197
Minimum ratio	8.00%	8.00%
Well capitalized amount	$ 1,824,395	$ 1,760,246
Well capitalized ratio	10.00%	10.00%
Actual amount	$ 2,150,760	$ 2,034,663
Actual ratio	11.79%	11.56%

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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings per common share - basic:
Net income	$ 52,018	$ 50,810	$ 102,491	$ 93,579
Preferred stock dividends	(949)	(854)	(4,548)	(3,430)
Dividends and undistributed earnings allocated to unvested restricted shares	(361)	(540)	(707)	(1,003)
Net income allocated to common shareholders - basic	$ 50,708	$ 49,416	$ 97,236	$ 89,146
Weighted average common shares outstanding	50,630	40,771	48,389	40,741
Earnings per common share - basic (in usd per share)	$ 1	$ 1.21	$ 2.01	$ 2.19
Earnings per common share - diluted:
Net income allocated to common shareholders - basic	$ 50,708	$ 49,416	$ 97,236	$ 89,146
Dividends and undistributed earnings allocated to unvested restricted shares	(2)	(12)	(39)	(13)
Earnings Allocated to Common Shareholders	$ 50,706	$ 49,404	$ 97,197	$ 89,133
Weighted average common shares outstanding	50,630	40,771	48,389	40,741
Dilutive potential common shares	354	137	362	86
Weighted average common shares outstanding - diluted	50,984	40,908	48,751	40,827
Earnings per common share - diluted (in usd per share)	$ 0.99	$ 1.21	$ 1.99	$ 2.18

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share
Weighted average number of shares held by Recognition and Retention Plan excluded from the calculation for basic shares outstanding	365,087	461,124	385,876	468,273
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from the computation of earnings per share	69,289	262,853	69,289	482,272

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future awards shares under approved incentive compensation plans	2,081,303	2,081,303
Share-based compensation maximum option term (in years)		10 years
Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned share-based compensation associated with awards	$ 2.5	$ 2.5
Unrecognized compensation cost related to stock options expected to be recognized over a weighted-average period		2 years 9 months 18 days
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned share-based compensation associated with awards	$ 20	$ 20	$ 21.1
Unrecognized compensation cost related to stock options expected to be recognized over a weighted-average period	1 year 7 months 6 days
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)		3 years
Phantom Stock Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)		5 years

Share-Based Compensation - Acti

Share-Based Compensation - Activity Related to Stock Options (Detail) - Stock Option Awards - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Number of shares
Balance at beginning of the period (in shares)	721,538,000	813,777,000
Granted (in shares)	71,491,000	149,932,000
Exercised (in shares)	(64,163,000)	(8,811,000)
Forfeited or expired (in shares)	(15,091,000)	(45,723,000)
Balance at end of the period (in shares)	713,775,000	909,175,000
Exercisable at period end (in shares)	470,841,000	598,469,000
Weighted Average Exercise Price
Balance at beginning of the period (in usd per share)	$ 55.38	$ 56.99
Granted (in usd per share)	85.42	47.46
Exercised (in usd per share)	55.05	55.62
Forfeited or expired (in usd per share)	74.72	60.97
Balance at end of the period (in usd per share)	58.01	55.23
Exercisable at period end (in usd per share)	$ 55.79	$ 56.31

Share-Based Compensation - Esti

Share-Based Compensation - Estimate Fair Value of Stock Option Awards with Weighted-Average Assumptions (Detail) - Stock Option Awards - $ / shares	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividends	1.70%		2.90%
Expected volatility	24.90%		29.10%
Risk-free interest rate	2.10%		1.40%
Expected term (in years)	5 years 7 months 6 days		6 years 6 months
Weighted-average grant-date fair value		$ 18.76	$ 10.10

Share-Based Compensation - Comp

Share-Based Compensation - Compensation Expense Included in Non-Interest Expense and Related Income Tax Benefits (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 344	$ 502	$ 789	$ 987
Income tax benefit	47	81	115	162
Restricted Stock And Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	3,045	3,329	6,322	6,715
Income tax benefit	1,066	1,165	2,213	2,350
Phantom Stock and Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 2,889	$ 2,793	$ 5,942	$ 5,198

Share-Based Compensation - Unve

Share-Based Compensation - Unvested Restricted Stock Award Activity (Detail) - Restricted Stock And Restricted Stock Units - shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of the period (in shares)	543,258,000	507,130,000
Granted (in shares)	163,353,000	240,699,000
Forfeited (in shares)	(9,951,000)	(9,040,000)
Earned and issued (in shares)	(185,092,000)	(172,356,000)
Balance at end of the period (in shares)	511,568,000	566,433,000

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Share and Dividend Equivalent Share Award Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Value of share equivalents
Market price of Company's stock	$ 81.50	$ 59.73
Phantom Stock and Performance Stock Units
Number of share equivalents
Balance at beginning of the period (in shares)	472,830,000	462,430,000
Granted (in shares)	105,048,000	192,359,000
Forfeited share equivalents (in shares)	(15,104,000)	(16,283,000)
Vested share equivalents (in shares)	(150,409,000)	(147,511,000)
Balance at end of the period (in shares)	412,365,000	490,995,000
Value of share equivalents
Balance at beginning of the period (in shares)	$ 39,600	$ 25,466
Granted (in shares)	8,561	11,490
Forfeited share equivalents (in shares)	(1,231)	(973)
Vested share equivalents (in shares)	(14,246)	(7,452)
Balance at end of the period (in shares)	$ 33,608	$ 29,327

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Assets
Securities available for sale, at fair value	$ 4,009,299,000	$ 3,446,097,000
Mortgage loans held for sale	140,959,000	157,041,000
Derivative instruments	28,761,000	28,804,000
Liabilities
Derivative instruments	19,425,000	21,244,000
Fair value assets transferred from Level 1 to Level 2	0
Recurring
Assets
Securities available for sale, at fair value	4,009,299,000	3,446,097,000
Mortgage loans held for sale	140,959,000	157,041,000
Derivative instruments	32,900,000	38,886,000
Total, Assets	4,183,158,000	3,642,024,000
Liabilities
Derivative instruments	28,684,000	30,209,000
Total	28,684,000	30,209,000
Recurring | Level 1
Assets
Securities available for sale, at fair value	0	0
Mortgage loans held for sale	0	0
Derivative instruments	0	0
Total, Assets	0	0
Liabilities
Derivative instruments	0	0
Total	0	0
Recurring | Level 2
Assets
Securities available for sale, at fair value	4,009,299,000	3,446,097,000
Mortgage loans held for sale	140,959,000	157,041,000
Derivative instruments	32,900,000	38,886,000
Total, Assets	4,183,158,000	3,642,024,000
Liabilities
Derivative instruments	28,684,000	30,209,000
Total	28,684,000	30,209,000
Recurring | Level 3
Assets
Securities available for sale, at fair value	0	0
Mortgage loans held for sale	0	0
Derivative instruments	0	0
Total, Assets	0	0
Liabilities
Derivative instruments	0	0
Total	$ 0	$ 0

Fair Value Measurements - Fin74

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets
Unpaid principal balance	$ 199,468	$ 292,645
Related allowance	2,181	1,358
Nonrecurring
Assets
Loans	97,363	93,485
OREO, net	2,871	185
Total	100,234	93,670
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	97,363	93,485
OREO, net	2,871	185
Total	$ 100,234	$ 93,670

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 ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Loans held fro investment at fair value	$ 13,300,000		$ 13,300,000		$ 12,700,000
Net gains (losses) resulting from change in fair value of loans held-for-investment			343,300	$ (65,400)
Mortgages Held For Sale at Fair Value
Aggregate fair value	140,959,000		140,959,000		157,041,000
Aggregate unpaid principal	137,524,000		137,524,000		153,801,000
Aggregate fair value less unpaid principal	3,435,000		3,435,000		$ 3,240,000
Net gains (losses) resulting from change in fair value of loans held-for-sale	$ 0	$ 2,000,000	$ 871,000	$ 3,900,000

Fair Value of Financial Instr76

Fair Value of Financial Instruments - Estimated Fair Values and Carrying Amounts of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Financial Assets
Cash and cash equivalents	$ 469,360	$ 1,362,126	$ 705,298	$ 510,267
Loans and loans held for sale, net of unearned income and allowance for loan losses	15,696,975		14,952,214
Derivative instruments	32,900	38,886
Financial Liabilities
Deposits	16,853,116	17,408,283	$ 15,862,027
Short-term borrowings	583,935	509,136
Long-term debt	667,243	628,953
Derivative instruments	28,684	30,209
Level 1
Financial Assets
Cash and cash equivalents	469,360	1,362,126
Investment securities	0	0
Loans and loans held for sale, net of unearned income and allowance for loan losses	0	0
Derivative instruments	0	0
Financial Liabilities
Deposits	0	0
Short-term borrowings	333,935	334,136
Long-term debt	0	0
Derivative instruments	0	0
Level 2
Financial Assets
Cash and cash equivalents	0	0
Investment securities	4,094,747	3,536,029
Loans and loans held for sale, net of unearned income and allowance for loan losses	140,959	157,041
Derivative instruments	32,900	38,886
Financial Liabilities
Deposits	0	0
Short-term borrowings	250,000	175,000
Long-term debt	0	0
Derivative instruments	28,684	30,209
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	15,526,610	14,909,014
Derivative instruments	0	0
Financial Liabilities
Deposits	15,817,343	16,762,475
Short-term borrowings	0	0
Long-term debt	658,483	617,656
Derivative instruments	0	0
Carrying Amount
Financial Assets
Cash and cash equivalents	469,360	1,362,126
Investment securities	4,093,816	3,535,313
Loans and loans held for sale, net of unearned income and allowance for loan losses	15,550,750	15,077,293
Derivative instruments	32,900	38,886
Financial Liabilities
Deposits	16,853,116	17,408,283
Short-term borrowings	583,935	509,136
Long-term debt	667,243	628,953
Derivative instruments	28,684	30,209
Fair Value
Financial Assets
Cash and cash equivalents	469,360	1,362,126
Investment securities	4,094,747	3,536,029
Loans and loans held for sale, net of unearned income and allowance for loan losses	15,667,569	15,066,055
Derivative instruments	32,900	38,886
Financial Liabilities
Deposits	15,817,343	16,762,475
Short-term borrowings	583,935	509,136
Long-term debt	658,483	617,656
Derivative instruments	$ 28,684	$ 30,209

Business Segments (Detail)

Business Segments (Detail)	3 Months Ended
	Jun. 30, 2017Segment
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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information
Interest and dividend income	$ 204,575	$ 178,694	$ 397,108	$ 355,630
Interest expense	20,932	15,941	40,647	31,474
Net interest income	183,643	162,753	356,461	324,156
Provision for loan losses	12,050	11,866	18,204	26,771
Mortgage income	19,730	25,991	33,845	45,931
Service charges on deposit accounts	11,410	10,940	22,563	21,891
Title revenue	6,190	6,135	10,931	10,880
Other non-interest income	18,636	21,851	35,973	42,060
Allocated expenses	0	0	0	0
Non-interest expense	147,508	139,504	288,526	276,956
Income before income tax expense	80,051	76,300	153,043	141,191
Income tax expense	28,033	25,490	50,552	47,612
Net income	52,018	50,810	102,491	93,579
Total loans and loans held for sale, net of unearned income	15,696,975	14,952,214	15,696,975	14,952,214
Total assets	21,790,727	20,160,855	21,790,727	20,160,855	$ 21,659,190
Total deposits	16,853,116	15,862,027	16,853,116	15,862,027	$ 17,408,283
Average assets	21,843,537	20,003,917	21,852,469	19,832,614
Operating Segments | IBERIABANK
Segment Reporting Information
Interest and dividend income	202,694	176,564	393,517	351,888
Interest expense	20,932	14,782	40,647	29,436
Net interest income	181,762	161,782	352,870	322,452
Provision for loan losses	12,134	11,866	18,292	26,771
Mortgage income	0	7	0	6
Service charges on deposit accounts	11,410	10,940	22,563	21,891
Title revenue	0	0	0	0
Other non-interest income	18,647	21,843	36,000	42,053
Allocated expenses	(3,322)	(3,885)	(5,496)	(6,554)
Non-interest expense	120,698	120,268	242,349	240,295
Income before income tax expense	82,309	66,323	156,288	125,890
Income tax expense	28,745	21,558	51,574	41,559
Net income	53,564	44,765	104,714	84,331
Total loans and loans held for sale, net of unearned income	15,504,171	14,702,843	15,504,171	14,702,843
Total assets	21,549,557	19,807,507	21,549,557	19,807,507
Total deposits	16,852,620	15,855,908	16,852,620	15,855,908
Average assets	21,593,026	19,668,456	21,572,094	19,525,087
Operating Segments | IMC
Segment Reporting Information
Interest and dividend income	1,881	2,130	3,590	3,741
Interest expense	0	1,159	0	2,038
Net interest income	1,881	971	3,590	1,703
Provision for loan losses	(84)	0	(88)	0
Mortgage income	19,730	25,984	33,845	45,925
Service charges on deposit accounts	0	0	0	0
Title revenue	0	0	0	0
Other non-interest income	(11)	8	(21)	7
Allocated expenses	2,490	2,947	4,146	4,997
Non-interest expense	22,417	14,820	37,584	28,018
Income before income tax expense	(3,223)	9,196	(4,228)	14,620
Income tax expense	(1,094)	3,625	(1,416)	5,778
Net income	(2,129)	5,571	(2,812)	8,842
Total loans and loans held for sale, net of unearned income	192,804	249,371	192,804	249,371
Total assets	215,862	326,397	215,862	326,397
Total deposits	496	6,119	496	6,119
Average assets	226,326	308,647	256,343	280,464
Operating Segments | LTC
Segment Reporting Information
Interest and dividend income	0	0	1	1
Interest expense	0	0	0	0
Net interest income	0	0	1	1
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	6,190	6,135	10,931	10,880
Other non-interest income	0	0	(6)	0
Allocated expenses	832	938	1,350	1,557
Non-interest expense	4,393	4,416	8,593	8,643
Income before income tax expense	965	781	983	681
Income tax expense	382	307	394	275
Net income	583	474	589	406
Total loans and loans held for sale, net of unearned income	0	0	0	0
Total assets	25,308	26,951	25,308	26,951
Total deposits	0	0	0	0
Average assets	$ 24,185	$ 26,814	$ 24,032	$ 27,063

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Fair value of guarantees under commercial and standby letters of credit	$ 1.8	$ 1.6
Pending Litigation
Loss Contingencies [Line Items]
Loss accrual	6
Pending Litigation | Minimum
Loss Contingencies [Line Items]
Estimate of possible loss	6
Pending Litigation | Maximum
Loss Contingencies [Line Items]
Estimate of possible loss	$ 17

Commitments and Contingencies80

Commitments and Contingencies - Summary of Financial Instruments Outstanding (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments to grant loans	$ 518,934	$ 355,558
Unfunded commitments under lines of credit	5,051,175	4,899,930
Commercial and standby letters of credit	183,031	163,560
Reserve for unfunded lending commitments	$ 10,462	$ 11,241	$ 13,826	$ 14,145

Related Party Transactions (Det

Related Party Transactions (Details) $ in Thousands	Jun. 30, 2017USD ($)bank	Feb. 28, 2017USD ($)	Dec. 31, 2016USD ($)
Related Party Transaction [Line Items]
Total debt outstanding to all lenders	$ 667,243		$ 628,953
Affiliated Entity | Stone Energy Corporation | Credit Facility
Related Party Transaction [Line Items]
Number of banks party to facility | bank	12
Affiliated Entity | Stone Energy Corporation | Exit Facility
Related Party Transaction [Line Items]
Borrowing base		$ 200,000
Affiliated Entity | Stone Energy Corporation | IBERIABANK | Credit Facility
Related Party Transaction [Line Items]
Percent of commitments held under facility	6.00%
Affiliated Entity | Stone Energy Corporation | IBERIABANK | Exit Facility
Related Party Transaction [Line Items]
Percent of commitments held under facility		5.90%
Outstanding balance to IBERIABANK		$ 11,800

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands, shares in Millions	Jul. 31, 2017USD ($)shares	Mar. 07, 2017offering	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Jun. 30, 2016USD ($)
Subsequent Event [Line Items]
Total Assets			$ 21,790,727	$ 21,659,190	$ 20,160,855
Total deposits			16,853,116	$ 17,408,283	$ 15,862,027
Sabadell United
Subsequent Event [Line Items]
Number of public stock offerings used to finance | offering		2
Total Assets			5,700,000
Gross loans			4,100,000
Total deposits			$ 4,400,000
Subsequent Event
Subsequent Event [Line Items]
Total Assets	$ 28,000,000
Subsequent Event | Sabadell United
Subsequent Event [Line Items]
Cash payment	$ 796,000
Number of shares paid | shares	2.6
Total consideration	$ 1,000,000