First Financial Bancorp. (FFBC) 10-Q 7 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	3 Months Ended
	Mar. 31, 2019	May 06, 2019
Document Information [Line Items]
Entity Emerging Growth Company	false
Entity Small Business	false
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	FFBC
Entity Registrant Name	FIRST FINANCIAL BANCORP /OH/
Entity Central Index Key	0000708955
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		98,613,714

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 169,004	$ 236,221
Interest-bearing deposits with other banks	50,224	37,738
Investment securities available-for-sale, at fair value (amortized cost $3,096,085 at March 31, 2019 and $2,792,326 at December 31, 2018)	3,113,811	2,779,255
Investment securities held-to-maturity (fair value $153,075 at March 31, 2019 and $424,118 at December 31, 2018)	158,305	429,328
Other investments	115,731	115,660
Loans held for sale	8,217	4,372
Loans
Commercial	2,543,427	2,514,661
Lease financing	95,573	93,415
Real estate - construction	458,113	548,935
Real estate-commercial	3,802,179	3,754,681
Real estate-residential	975,120	955,646
Home equity	797,118	817,282
Installment	90,689	93,212
Credit card	46,982	46,382
Total loans and leases	8,809,201	8,824,214
Loans and Leases Receivable, Allowance	56,722	56,542
Net loans and leases	8,752,479	8,767,672
Premises and equipment	210,676	215,652
Goodwill	879,727	880,251
Other Finite-Lived Intangible Assets, Gross	38,571	40,805
Accrued interest and other assets	577,518	479,706
Total assets	14,074,263	13,986,660
Deposits
Interest-bearing	2,235,036	2,307,071
Savings	3,100,894	3,167,325
Time	2,309,810	2,173,564
Total interest-bearing deposits	7,645,740	7,647,960
Noninterest-bearing	2,488,157	2,492,434
Total deposits	10,133,897	10,140,394
Federal funds purchased	95,015	183,591
FHLB short-term borrowings	952,400	857,100
Total short-term borrowings	1,047,415	1,040,691
Long-term debt	546,423	570,739
Total borrowed funds	1,593,838	1,611,430
Accrued interest and other liabilities	216,109	156,587
Total liabilities	11,943,844	11,908,411
SHAREHOLDERS' EQUITY
Common stock - no par value Authorized - 160,000,000 shares Issued - 104,281,794 shares in 2018 and 68,730,731 shares in 2017	1,622,554	1,633,256
Retained earnings	626,408	600,014
Accumulated other comprehensive loss	(19,635)	(44,408)
Treasury stock, at cost, 5,667,922 shares in 2019 and 6,387,508 shares in 2018	(98,908)	(110,613)
Total shareholders' equity	2,130,419	2,078,249
Total liabilities and shareholders' equity	$ 14,074,263	$ 13,986,660

CONSOLIDATED BALANCE SHEETS CON

CONSOLIDATED BALANCE SHEETS CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Available-for-sale Securities, Amortized Cost Basis	$ 3,096,085	$ 2,792,326
Debt Securities, Held-to-maturity, Fair Value	$ 153,075	$ 424,118
Common Stock, No Par Value	$ 0	$ 0
Common Stock, Shares Authorized	160,000,000	160,000,000
Common Stock, Shares, Issued	104,281,794	104,281,794
Treasury Stock, Shares	5,667,922	6,387,508

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest income
Loans, including fees	$ 123,056	$ 74,920
Investment securities
Taxable	24,235	13,670
Tax-exempt	4,258	1,657
Total interest on investment securities	28,493	15,327
Other earning assets	210	107
Total interest income	151,759	90,354
Interest expense
Deposits	19,243	10,298
Short-term borrowings	5,960	2,663
Long-term borrowings	5,041	1,581
Total interest expense	30,244	14,542
Net interest income	121,515	75,812
Provision for Loan and Lease Losses	14,083	2,303
Net interest income after provision for loan and lease losses	107,432	73,509
Noninterest income
Service Charges on Deposit Accounts	8,903	5,039
Trust and wealth management fees	4,070	3,954
Bankcard income	5,586	3,394
Client derivative fees	1,704	1,757
Net gain from sales of loans	1,890	588
Net gain (loss) on sales/transfers of investment securities	(178)	0
Other	4,852	2,206
Total noninterest income	26,827	16,938
Noninterest expenses
Salaries and employee benefits	47,912	31,102
Net occupancy	6,630	4,497
Furniture and equipment	3,416	2,040
Data processing	5,127	3,672
Marketing	1,606	801
Communication	728	459
Professional services	2,252	2,198
State intangible tax	1,310	765
FDIC assessments	950	894
Amortization of Intangible Assets	2,045	280
Other	6,523	5,580
Total noninterest expenses	78,499	52,288
Income before income taxes	55,760	38,159
Income tax expense	9,921	7,653
Net income	$ 45,839	$ 30,506
Earnings per common share
Basic	$ 0.47	$ 0.49
Diluted	0.47	0.49
Cash dividends declared per share	$ 0.22	$ 0.19
Average common shares outstanding - basic	97,926,088	61,654,686
Average common shares outstanding - diluted	98,436,311	62,180,744

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 45,839	$ 30,506
Other comprehensive (loss) income, net of tax
Unrealized gain (loss) on debt securities arising during the period	23,505	(9,830)
Change in retirement obligation	290	323
Unrealized gain (loss) on derivatives	72	156
Other comprehensive income (loss)	23,867	(9,351)
Comprehensive income	$ 69,706	$ 21,155

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock
Beginning Balances (in shares) at Dec. 31, 2017		68,730,731			(6,661,644)
Beginning Balances at Dec. 31, 2017	$ 930,664	$ 573,109	$ 491,847	$ (20,390)	$ (113,902)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	0		5,093	(5,093)
Net income	30,506		30,506
Other comprehensive income (loss)	(9,351)			(9,351)
Cash dividends declared :
Common stock at $0.22 per share in 2019 and $0.19 per share in 2018	(11,797)		(11,797)
Stock Issued During Period, Shares, Other					1,428
Adjustments to Additional Paid in Capital, Other	0	(24)			$ 24
Exercise of stock options, net of shares purchased (in shares)					11,800
Exercise of stock options, net of shares purchased	137	(65)			$ 202
Restricted stock awards, net of forfeitures (in shares)					131,508
Restricted stock awards, net of forfeitures	(2,128)	(3,517)			$ 1,389
Share-based compensation expense	1,954	$ 1,954
Ending Balances (in shares) at Mar. 31, 2018		68,730,731			(6,516,908)
Ending Balances at Mar. 31, 2018	939,985	$ 571,457	515,649	(34,834)	$ (112,287)
Beginning Balances (in shares) at Dec. 31, 2018		104,281,794			(6,387,508)
Beginning Balances at Dec. 31, 2018	2,078,249	$ 1,633,256	600,014	(44,408)	$ (110,613)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	3,127		2,221	906
Net income	45,839		45,839
Other comprehensive income (loss)	23,867			23,867
Cash dividends declared :
Common stock at $0.22 per share in 2019 and $0.19 per share in 2018	(21,666)		(21,666)
Stock Issued During Period, Shares, Other					452,134
Adjustments to Additional Paid in Capital, Other	0	(7,830)			$ 7,830
Exercise of stock options, net of shares purchased (in shares)					20,424
Exercise of stock options, net of shares purchased	90	(264)			$ 354
Restricted stock awards, net of forfeitures (in shares)					247,028
Restricted stock awards, net of forfeitures	(2,083)	(5,604)			$ 3,521
Share-based compensation expense	2,996	$ 2,996
Ending Balances (in shares) at Mar. 31, 2019		104,281,794			(5,667,922)
Ending Balances at Mar. 31, 2019	$ 2,130,419	$ 1,622,554	$ 626,408	$ (19,635)	$ (98,908)

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Common Stock, Dividends, Per Share, Declared	$ 0.22	$ 0.19

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net income	$ 45,839	$ 30,506
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	14,083	2,303
Depreciation and amortization	6,489	3,076
Stock-based compensation expense	2,996	1,954
Pension expense (income)	375	(156)
Net amortization (accretion) on investment securities	2,649	2,801
Net (gain) loss on sales of investment securities	178	0
Originations of loans held for sale	(41,227)	(22,383)
Net gains from sales of loans held for sale	(1,890)	(588)
Proceeds from sales of loans held for sale	39,273	24,542
Deferred income taxes	12,625	(1,736)
Amortization of operating leases	1,826	0
Operating Lease, Payments	(1,823)	0
Decrease (increase) cash surrender value of life insurance	1,534	(786)
Decrease (increase) in interest receivable	(3,109)	(1,687)
(Decrease) increase in interest payable	322	(1,013)
Decrease (increase) in other assets	(30,168)	15,414
(Decrease) increase in other liabilities	(8,908)	(1,491)
Net cash provided by (used in) operating activities	37,996	52,328
Investing activities
Proceeds from sales of securities available-for-sale	0	0
Proceeds from calls, paydowns and maturities of securities available-for-sale	95,114	52,252
Purchases of securities available-for-sale	(143,290)	(77,037)
Proceeds from calls, paydowns and maturities of securities held-to-maturity	2,398	19,718
Net decrease (increase) in interest-bearing deposits with other banks	(12,486)	23,774
Net decrease (increase) in loans and leases	438	(89,526)
Proceeds from disposal of other real estate owned	183	2,222
Purchases of premises and equipment	(1,268)	(4,979)
Net cash provided by (used in) investing activities	(58,911)	(73,576)
Financing activities
Net (decrease) increase in total deposits	(6,379)	115,458
Net (decrease) increase in short-term borrowings	6,724	(156,233)
Payments of long-term debt	25,187	0
Proceeds from FHLB borrowings	0	50,000
Cash dividends paid on common stock	(21,550)	(22,183)
Proceeds from exercise of stock options	90	137
Net cash provided by (used in) financing activities	(46,302)	(12,821)
Cash and due from banks:
Change in cash and due from banks	(67,217)	(34,069)
Cash and due from banks at beginning of period	236,221	150,650
Cash and due from banks at end of period	169,004	$ 116,581
Supplemental schedule for investing activities
Goodwill	$ (524)

BASIS OF PRESENTATION

BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION The Consolidated Financial Statements of First Financial Bancorp., a financial holding company principally serving Ohio, Indiana, Kentucky and Illinois, include the accounts and operations of First Financial and its wholly-owned subsidiary, First Financial Bank. All significant intercompany transactions and accounts have been eliminated in consolidation. Certain reclassifications of prior periods' amounts have been made to conform to current year presentation. Such reclassifications had no effect on net earnings. The preparation of financial statements in conformity with GAAP requires management to make estimates, assumptions and judgments that affect the amounts reported in the Consolidated Financial Statements and accompanying Notes. These estimates, assumptions and judgments are inherently subjective and may be susceptible to significant change. Actual realized amounts could differ materially from these estimates. These interim financial statements have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they may not include all of the information and accompanying notes necessary to constitute a complete set of financial statements required by GAAP and should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 . Management believes these unaudited consolidated financial statements reflect all adjustments of a normal recurring nature which are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. The Consolidated Balance Sheet as of December 31, 2018 has been derived from the audited financial statements in the Company’s 2018

RECENTLY ADOPTED AND ISSUED ACC

RECENTLY ADOPTED AND ISSUED ACCOUNTING STANDARDS	3 Months Ended
	Mar. 31, 2019
Recently Adopted and Issued Accounting Standards [Abstract]
Recently Adopted and Issued Accounting Standards Disclosure [Text Block]	RECENTLY ADOPTED AND ISSUED ACCOUNTING STANDARDS Accounting Guidance Adopted in 2019 In February 2016, the FASB issued an update (ASU 2016-02, Leases) which requires lessees to record most leases on their balance sheet and recognize leasing expenses in the income statement. Operating leases where the Bank is the lessee, except for short-term leases that are subject to an accounting policy election, were recorded on the balance sheet by establishing a lease liability and corresponding ROU asset. All entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. As the Company elected the transition option provided in ASU No. 2018-11, the modified retrospective approach was applied on January 1, 2019 (as opposed to January 1, 2017). The Company also elected certain relief options offered in ASU 2016-02 including the package of practical expedients, the option not to separate lease and non-lease components and instead to account for them as a single lease component and the option not to recognize ROU assets and lease liabilities that arise from short-term leases. The Company did not elect the hindsight practical expedient, which allows entities to use hindsight when determining lease term and impairment of ROU assets. The guidance in this ASU became effective January 1, 2019 at which time the Company recorded on the Consolidated Balance Sheet an ROU asset of $60.2 million and a lease liability of $65.8 million . For further detail, see Note 7 – Leases. In March 2017, the FASB issued an update (ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities) which amended the amortization period for certain purchased callable debt securities held at a premium and shortens the amortization period for the premium to the earliest call date rather than as an adjustment of yield over the contractual life of the instrument. This update more closely aligns the amortization period of premiums and discounts to expectations incorporated in market pricing on the underlying securities, as in most cases, market participants price securities to the call date that produces the worst yield when the coupon is above current market rates (that is, the security is trading at a premium) and price securities to maturity when the coupon is below market rates (that is, the security is trading at a discount) in anticipation that the borrower will act in its economic best interest in an attempt to more closely align interest income recorded on bonds held at a premium or a discount with the economics of the underlying instrument. The guidance in this ASU became effective in January 1, 2019 and did not have a material impact on the Consolidated Financial Statements. In August 2017, the FASB issued an update (ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities) to better align financial reporting for hedging activities with the economic objectives of those activities. This update aligns certain aspects of hedge documentation, effectiveness assessments, accounting and disclosures and expands permissible hedge strategies as of the date of adoption. The guidance in this ASU became effective January 1, 2019. Upon adoption, the Company reclassified $268.7 million of HTM securities to AFS, resulting in a $0.2 million loss in the Consolidated Statement of Income. Accounting Guidance Issued But Not Yet Adopted In June 2016, the FASB issued an update (ASU 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments) which significantly changes how entities are required to measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. This update will replace the current incurred loss approach for estimating credit losses with an expected loss model for instruments measured at amortized cost, including loans and leases. Expected credit losses are required to be based on amortized cost and reflect losses expected over the remaining contractual life of the asset. Management is expected to consider any available information relevant to assessing the collectibility of contractual cash flows, such as information about past events, current conditions, voluntary prepayments and reasonable and supportable forecasts, when developing expected credit loss estimates. In addition to the new framework for calculating the ALLL, this update requires allowances for available-for-sale debt securities rather than a reduction of the security's carrying amount under the current other-than-temporary impairment model. This update also simplifies the accounting model for purchased credit-impaired debt securities and loans and will require new and updated footnote disclosures. The guidance in this ASU will become effective for interim and annual reporting periods beginning after December 15, 2019. First Financial currently expects as of January 1, 2020 to recognize a one-time cumulative effect adjustment to increase the ALLL with an offsetting reduction to the retained earnings component of equity. In December 2018, the federal bank regulatory agencies approved a final rule that modifies their regulatory capital rules and provides institutions the option to phase in over a three-year period any day-one regulatory capital effects of this update. First Financial has formed an internal management committee and engaged a third party vendor to assist with the transition to the guidance set forth in this update. The committee is currently evaluating the impact of this update on First Financial’s Consolidated Financial Statements, but the ALLL is expected to increase upon adoption since the allowance will be required to cover the full expected life of the portfolio. The extent of this increase is still being evaluated and will depend on economic conditions and the composition of the loan and lease portfolio at the time of adoption. Management is currently evaluating the preliminary modeling results, including a qualitative framework to account for the drivers of credit losses that are not captured by the quantitative model.

INVESTMENTS

INVESTMENTS	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS For the three months ended March 31, 2019 and March 31, 2018 , there were no sales of AFS securities and therefore no associated gains or losses. In conjunction with the adoption of ASU 2017-12 in the first quarter of 2019, First Financial reclassified $268.7 million of HTM securities to AFS resulting in a $0.2 million realized loss recorded in the Consolidated Statement of Income. The following is a summary of HTM and AFS investment securities as of March 31, 2019 : Held-to-maturity Available-for-sale (Dollars in thousands) Amortized Unrecognized gain Unrecognized loss Fair Amortized cost Unrealized gain Unrealized loss Fair U.S. Treasuries $ 0 $ 0 $ 0 $ 0 $ 99 $ 0 $ (1 ) $ 98 Securities of U.S. government agencies and corporations 0 0 0 0 30,880 74 (355 ) 30,599 Mortgage-backed securities - residential 24,937 72 (671 ) 24,338 557,730 4,566 (3,449 ) 558,847 Mortgage-backed securities - commercial 109,826 0 (4,414 ) 105,412 464,611 1,821 (2,988 ) 463,444 Collateralized mortgage obligations 11,936 0 (429 ) 11,507 919,486 9,214 (3,067 ) 925,633 Obligations of state and other political subdivisions 11,606 440 (228 ) 11,818 542,265 12,496 (504 ) 554,257 Asset-backed securities 0 0 0 0 502,018 1,180 (1,790 ) 501,408 Other securities 0 0 0 0 78,996 853 (324 ) 79,525 Total $ 158,305 $ 512 $ (5,742 ) $ 153,075 $ 3,096,085 $ 30,204 $ (12,478 ) $ 3,113,811 The following is a summary of HTM and AFS investment securities as of December 31, 2018 : Held-to-maturity Available-for-sale (Dollars in thousands) Amortized Unrecognized gain Unrecognized Fair Amortized Unrealized Unrealized Fair U.S. Treasuries $ 0 $ 0 $ 0 $ 0 $ 99 $ 0 $ (2 ) $ 97 Securities of U.S. government agencies and corporations 0 0 0 0 32,095 57 (233 ) 31,919 Mortgage-backed securities - residential 25,565 0 (1,045 ) 24,520 565,071 691 (7,163 ) 558,599 Mortgage-backed securities - commercial 147,780 258 (4,385 ) 143,653 423,797 819 (3,581 ) 421,035 Collateralized mortgage obligations 12,540 0 (633 ) 11,907 928,586 4,319 (6,158 ) 926,747 Obligations of state and other political subdivisions 243,443 1,954 (1,359 ) 244,038 257,300 2,554 (1,429 ) 258,425 Asset-backed securities 0 0 0 0 511,430 611 (2,810 ) 509,231 Other securities 0 0 0 0 73,948 358 (1,104 ) 73,202 Total $ 429,328 $ 2,212 $ (7,422 ) $ 424,118 $ 2,792,326 $ 9,409 $ (22,480 ) $ 2,779,255 The following table provides a summary of investment securities by contractual maturity as of March 31, 2019 , except for residential and commercial mortgage-backed securities, collateralized mortgage obligations and asset-backed securities, which are shown as single totals due to the unpredictability of the timing in principal repayments. Held-to-maturity Available-for-sale (Dollars in thousands) Amortized cost Fair value Amortized cost Fair value By Contractual Maturity: Due in one year or less $ 0 $ 0 $ 18,503 $ 18,522 Due after one year through five years 0 0 52,079 52,547 Due after five years through ten years 4,247 4,579 162,531 165,532 Due after ten years 7,359 7,239 419,127 427,878 Mortgage-backed securities - residential 24,937 24,338 557,730 558,847 Mortgage-backed securities - commercial 109,826 105,412 464,611 463,444 Collateralized mortgage obligations 11,936 11,507 919,486 925,633 Asset-backed securities 0 0 502,018 501,408 Total $ 158,305 $ 153,075 $ 3,096,085 $ 3,113,811 Unrealized gains and losses on debt securities are generally due to fluctuations in current market yields relative to the yields of the debt securities at their amortized cost. All securities with unrealized losses are reviewed quarterly to determine if any impairment is considered other than temporary, requiring a write-down to fair value. First Financial considers the percentage loss on a security, duration of the loss, average life or duration of the security, credit rating of the security and payment performance, as well as the Company's intent and ability to hold the security to maturity, when determining whether any impairment is other than temporary. At this time, First Financial does not intend to sell, and it is not more likely than not that the Company will be required to sell, debt securities temporarily impaired prior to maturity or recovery of the recorded value. First Financial had no other than temporary impairment related to its investment securities portfolio as of March 31, 2019 or December 31, 2018 . As of March 31, 2019 , the Company's investment securities portfolio consisted of 1,395 securities, of which 303 were in an unrealized loss position. As of December 31, 2018, the Company's investment securities portfolio consisted of 1,417 securities, of which 504 were in an unrealized loss position. The following tables provide the fair value and gross unrealized losses on investment securities in an unrealized loss position, aggregated by investment category and the length of time the individual securities have been in a continuous loss position: March 31, 2019 Less than 12 months 12 months or more Total (Dollars in thousands) Fair value Unrealized loss Fair Unrealized Fair Unrealized U.S. Treasuries $ 0 $ 0 $ 98 $ (1 ) $ 98 $ (1 ) Securities of U.S. Government agencies and corporations 6,046 (77 ) 13,946 (278 ) 19,992 (355 ) Mortgage-backed securities - residential 12,585 (322 ) 239,305 (3,798 ) 251,890 (4,120 ) Mortgage-backed securities - commercial 140,670 (264 ) 195,282 (7,138 ) 335,952 (7,402 ) Collateralized mortgage obligations 90,610 (431 ) 212,286 (3,065 ) 302,896 (3,496 ) Obligations of state and other political subdivisions 12,080 (30 ) 42,954 (702 ) 55,034 (732 ) Asset-backed securities 224,565 (1,325 ) 48,376 (465 ) 272,941 (1,790 ) Other securities 8,636 (78 ) 7,545 (246 ) 16,181 (324 ) Total $ 495,192 $ (2,527 ) $ 759,792 $ (15,693 ) $ 1,254,984 $ (18,220 ) December 31, 2018 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized (Dollars in thousands) value loss value loss value loss U.S. Treasuries $ 0 $ 0 $ 97 $ (2 ) $ 97 $ (2 ) Securities of U.S. Government agencies and corporations 0 0 16,777 (233 ) 16,777 (233 ) Mortgage-backed securities - residential 186,029 (935 ) 264,795 (7,273 ) 450,824 (8,208 ) Mortgage-backed securities - commercial 147,754 (369 ) 232,363 (7,597 ) 380,117 (7,966 ) Collateralized mortgage obligations 194,795 (1,546 ) 240,514 (5,245 ) 435,309 (6,791 ) Obligations of state and other political subdivisions 62,805 (299 ) 86,644 (2,489 ) 149,449 (2,788 ) Asset-backed securities 336,437 (2,312 ) 37,105 (498 ) 373,542 (2,810 ) Other securities 33,752 (884 ) 4,570 (220 ) 38,322 (1,104 ) Total $ 961,572 $ (6,345 ) $ 882,865 $ (23,557 ) $ 1,844,437 $ (29,902 )

LOANS AND LEASES

LOANS AND LEASES	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
LOANS AND LEASES	LOANS AND LEASES First Financial offers clients a variety of commercial and consumer loan and lease products with distinct interest rates and payment terms. Commercial loan categories include C&I, CRE, construction real estate and lease financing. Consumer loan categories include residential real estate, home equity, installment and credit card. Lending activities are primarily concentrated in states where the Bank operates banking centers (Ohio, Indiana, Kentucky and Illinois). First Financial also offers two nationwide lending platforms, one that provides equipment and leasehold improvement financing for franchisees in the quick service and casual dining restaurant sector and another that primarily provides loans that are secured by commissions and cash collateral to insurance agents and brokers. Credit Quality. To facilitate the monitoring of credit quality for commercial loans, and for purposes of determining an appropriate ALLL, First Financial utilizes the following categories of credit grades: Pass - Higher quality loans that do not fit any of the other categories described below. Special Mention - First Financial assigns a special mention rating to loans and leases with potential weaknesses that deserve management's close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loan or lease or in First Financial's credit position at some future date. Substandard - First Financial assigns a substandard rating to loans or leases that are inadequately protected by the current sound financial worth and paying capacity of the borrower or of the collateral pledged, if any. Substandard loans and leases have well-defined weaknesses that jeopardize repayment of the debt. Substandard loans and leases are characterized by the distinct possibility that the Company will sustain some loss if the deficiencies are not addressed. Doubtful - First Financial assigns a doubtful rating to loans and leases with all the attributes of a substandard rating with the added characteristic that the weaknesses make collection or liquidation in full highly questionable and improbable, on the basis of currently existing facts, conditions and values. The possibility of loss is extremely high, but because of certain important and reasonably specific pending factors that may work to the advantage and strengthening of the credit quality of the loan or lease, its classification as an estimated loss is deferred until its more exact status may be determined. Pending factors include proposed merger, acquisition or liquidation procedures, capital injection, perfecting liens on additional collateral and refinancing plans. The credit grades previously described are derived from standard regulatory rating definitions and are assigned upon initial approval of credit to borrowers and updated periodically thereafter. First Financial considers repayment performance to be the best indicator of credit quality for consumer loans. Consumer loans that have principal and interest payments that are past due by 90 days or more are generally classified as nonperforming. Additionally, consumer loans that have been modified in a TDR are classified as nonperforming. Purchased impaired loans are not classified as nonperforming as the loans are considered to be performing under FASB ASC Topic 310-30. Commercial and consumer credit exposure by risk attribute was as follows: As of March 31, 2019 Commercial Real Estate Lease (Dollars in thousands) & industrial Construction Commercial financing Total Pass $ 2,443,488 $ 457,508 $ 3,720,197 $ 92,527 $ 6,713,720 Special Mention 36,936 0 25,935 365 63,236 Substandard 63,003 605 56,047 2,681 122,336 Doubtful 0 0 0 0 0 Total $ 2,543,427 $ 458,113 $ 3,802,179 $ 95,573 $ 6,899,292 (Dollars in thousands) Residential real estate Home equity Installment Credit card Total Performing $ 958,185 $ 790,893 $ 90,515 $ 46,827 $ 1,886,420 Nonperforming 16,935 6,225 174 155 23,489 Total $ 975,120 $ 797,118 $ 90,689 $ 46,982 $ 1,909,909 As of December 31, 2018 Commercial Real Estate Lease (Dollars in thousands) & industrial Construction Commercial financing Total Pass $ 2,432,834 $ 548,323 $ 3,664,434 $ 90,902 $ 6,736,493 Special Mention 24,594 603 38,653 0 63,850 Substandard 57,233 9 51,594 2,513 111,349 Doubtful 0 0 0 0 0 Total $ 2,514,661 $ 548,935 $ 3,754,681 $ 93,415 $ 6,911,692 (Dollars in thousands) Residential real estate Home equity Installment Credit card Total Performing $ 939,936 $ 811,108 $ 93,038 $ 46,382 $ 1,890,464 Nonperforming 15,710 6,174 174 0 22,058 Total $ 955,646 $ 817,282 $ 93,212 $ 46,382 $ 1,912,522 Delinquency. Loans are considered past due or delinquent when the contractual principal or interest due in accordance with the terms of the loan agreement remains unpaid after the date of the scheduled payment. Loan delinquency, including loans classified as nonaccrual, was as follows: As of March 31, 2019 (Dollars in thousands) 30 – 59 60 – 89 > 90 days Total Current Subtotal Purchased impaired Total > 90 days Loans Commercial & industrial $ 917 $ 7,797 $ 8,255 $ 16,969 $ 2,521,040 $ 2,538,009 $ 5,418 $ 2,543,427 $ 23 Lease financing 0 0 0 0 95,573 95,573 0 95,573 0 Construction real estate 0 598 0 598 457,323 457,921 192 458,113 0 Commercial real estate 1,695 1,103 13,462 16,260 3,738,962 3,755,222 46,957 3,802,179 0 Residential real estate 3,329 1,495 4,326 9,150 933,896 943,046 32,074 975,120 0 Home equity 2,960 1,046 2,702 6,708 787,129 793,837 3,281 797,118 0 Installment 317 30 84 431 89,837 90,268 421 90,689 0 Credit card 193 206 155 554 46,428 46,982 0 46,982 155 Total $ 9,411 $ 12,275 $ 28,984 $ 50,670 $ 8,670,188 $ 8,720,858 $ 88,343 $ 8,809,201 $ 178 As of December 31, 2018 (Dollars in thousands) 30 – 59 60 – 89 > 90 days Total Current Subtotal Purchased impaired Total > 90 days Loans Commercial & industrial $ 13,369 $ 41 $ 7,423 $ 20,833 $ 2,488,450 $ 2,509,283 $ 5,378 $ 2,514,661 $ 0 Lease financing 352 0 0 352 93,063 93,415 0 93,415 0 Construction real estate 0 0 0 0 548,687 548,687 248 548,935 0 Commercial real estate 6,279 1,158 12,644 20,081 3,682,455 3,702,536 52,145 3,754,681 0 Residential real estate 11,060 2,976 4,535 18,571 902,404 920,975 34,671 955,646 0 Home equity 5,245 1,228 2,578 9,051 804,835 813,886 3,396 817,282 0 Installment 420 37 145 602 92,128 92,730 482 93,212 0 Credit card 541 96 63 700 45,682 46,382 0 46,382 63 Total $ 37,266 $ 5,536 $ 27,388 $ 70,190 $ 8,657,704 $ 8,727,894 $ 96,320 $ 8,824,214 $ 63 Nonaccrual. Loans are classified as nonaccrual when, in the opinion of management, collection of principal or interest is doubtful or when principal or interest payments are 90 days or more past due. Generally, loans are classified as nonaccrual due to the continued failure to adhere to contractual payment terms by the borrower, coupled with other pertinent factors. When a loan is classified as nonaccrual, the accrual of interest income is discontinued and previously accrued but unpaid interest is reversed. Any payments received while a loan is on nonaccrual status are applied as a reduction to the carrying value of the loan. A loan classified as nonaccrual may return to accrual status if none of the principal and interest due and unpaid, and the Bank expects repayment of the remaining contractual principal and interest. Purchased impaired loans are classified as performing, even though they may be contractually past due, as any nonpayment of contractual principal or interest is considered in the periodic re-estimation of expected cash flows and is included in the resulting recognition of current period provision for loan and lease losses or prospective yield adjustments. Troubled Debt Restructurings. A loan modification is considered a TDR when the borrower is experiencing financial difficulty and concessions are made by the Company that would not otherwise be considered for a borrower with similar credit characteristics. The most common types of modifications include interest rate reductions, maturity extensions and modifications to principal amortization, including interest-only structures. Modified terms are dependent upon the financial position and needs of the individual borrower. If the modification agreement is violated, the loan is managed by the Company’s credit administration group for resolution, which may result in foreclosure in the case of real estate. TDRs are generally classified as nonaccrual for a minimum period of six months and may qualify for return to accrual status once they have demonstrated performance with the restructured terms of the loan agreement. First Financial had 201 TDRs totaling $35.9 million at March 31, 2019 , including $22.8 million on accrual status and $13.1 million classified as nonaccrual. First Financial had no commitments outstanding to lend additional funds to borrowers whose loan terms have been modified through TDRs, and the ALLL included reserves of $1.4 million related to TDRs at March 31, 2019 . Additionally, as of March 31, 2019 , $7.5 million of accruing TDRs have been performing in accordance with the restructured terms for more than one year. First Financial had 196 TDRs totaling $38.5 million at December 31, 2018 , including $16.1 million of loans on accrual status and $22.4 million classified as nonaccrual. First Financial had no commitments outstanding to lend additional funds to borrowers whose loan terms had been modified through TDRs. At December 31, 2018 , the ALLL included reserves of $1.5 million related to TDRs, and $7.9 million of the accruing TDRs had been performing in accordance with the restructured terms for more than one year. The following tables provide information on loan modifications classified as TDRs during the three months ended March 31, 2019 and 2018 : Three months ended March 31, 2019 March 31, 2018 (Dollars in thousands) Number of loans Pre-modification loan balance Period end balance Number of loans Pre-modification loan balance Period end balance Commercial & industrial 5 $ 7,637 $ 7,661 4 $ 928 $ 913 Construction real estate 0 0 0 0 0 0 Commercial real estate 6 1,323 1,232 2 72 72 Residential real estate 5 458 458 2 93 93 Home equity 1 17 17 0 0 0 Installment 0 0 0 0 0 0 Total 17 $ 9,435 $ 9,368 8 $ 1,093 $ 1,078 For TDRs identified during the three months ended March 31, 2019 and 2018, there were no chargeoffs for the portion of TDRs determined to be uncollectible. The following table provides information on how TDRs were modified during the three months ended March 31, 2019 and 2018 : Three months ended March 31, (Dollars in thousands) 2019 2018 Extended maturities $ 2,877 $ 888 Adjusted interest rates 5,284 52 Combination of rate and maturity changes 508 0 Forbearance 557 0 Other (1) 142 138 Total $ 9,368 $ 1,078 (1) Includes covenant modifications and other concessions, or combination of concessions, that do not consist of interest rate adjustments, forbearance and maturity extensions First Financial considers repayment performance as an indication of the effectiveness of the Company's loan modifications. Borrowers that are 90 days or more past due on any principal or interest payments, or who prematurely terminate a restructured loan agreement without paying the contractual principal balance (for example, in a deed-in-lieu arrangement), are considered to be in payment default of the terms of the TDR agreement. For the three months ended March 31, 2019 , there were two TDR relationships for $6.9 million , for which there was a payment default during the period that occurred within twelve months of the loan modification. There were no TDRs for which there was a payment default during the period that occurred within twelve months of the loan modification for the three months ended March 31, 2018 . Impaired Loans. Loans classified as nonaccrual and loans modified as TDRs are considered impaired. The following table provides information on impaired loans, excluding purchased impaired loans: (Dollars in thousands) March 31, 2019 December 31, 2018 Impaired loans Nonaccrual loans (1) Commercial & industrial $ 19,263 $ 30,925 Lease financing 301 22 Construction real estate 7 9 Commercial real estate 21,082 20,500 Residential real estate 13,052 13,495 Home equity 5,581 5,580 Installment 170 169 Nonaccrual loans 59,456 70,700 Accruing troubled debt restructurings 22,817 16,109 Total impaired loans $ 82,273 $ 86,809 (1) Nonaccrual loans include nonaccrual TDRs of $13.1 million and $22.4 million as of March 31, 2019 and December 31, 2018 , respectively. Three months ended March 31, (Dollars in thousands) 2019 2018 Interest income effect on impaired loans Gross amount of interest that would have been recorded under original terms $ 1,613 $ 802 Interest included in income Nonaccrual loans 335 80 Troubled debt restructurings 236 124 Total interest included in income 571 204 Net impact on interest income $ 1,042 $ 598 First Financial individually reviews all impaired commercial loan relationships, as well as consumer loan TDRs, greater than $250,000 , to determine if a specific allowance is necessary based on the borrower’s overall financial condition, payment record, support from guarantors and the realizable value of any collateral. Specific allowances are based on discounted cash flows using the loan's initial effective interest rate or the fair value of the collateral for certain collateral dependent loans. First Financial's investment in impaired loans was as follows: As of March 31, 2019 As of December 31, 2018 (Dollars in thousands) Current balance Contractual principal balance Related allowance Current balance Contractual Related Loans with no related allowance recorded Commercial & industrial $ 30,142 $ 46,215 $ 0 $ 36,694 $ 42,561 $ 0 Lease financing 301 301 0 22 22 0 Construction real estate 8 25 0 9 26 0 Commercial real estate 22,708 29,530 0 23,513 31,375 0 Residential real estate 16,637 19,237 0 17,297 19,975 0 Home equity 6,225 7,232 0 6,351 7,461 0 Installment 174 310 0 174 563 0 Total 76,195 102,850 0 84,060 101,983 0 Loans with an allowance recorded Commercial & industrial 3,282 3,282 738 939 939 667 Lease financing 0 0 0 0 0 0 Construction real estate 0 0 0 0 0 0 Commercial real estate 2,498 3,579 651 1,509 1,509 461 Residential real estate 298 298 31 301 301 32 Home equity 0 0 0 0 0 0 Installment 0 0 0 0 0 0 Total 6,078 7,159 1,420 2,749 2,749 1,160 Total Commercial & industrial 33,424 49,497 738 37,633 43,500 667 Lease financing 301 301 0 22 22 0 Construction real estate 8 25 0 9 26 0 Commercial real estate 25,206 33,109 651 25,022 32,884 461 Residential real estate 16,935 19,535 31 17,598 20,276 32 Home equity 6,225 7,232 0 6,351 7,461 0 Installment 174 310 0 174 563 0 Total $ 82,273 $ 110,009 $ 1,420 $ 86,809 $ 104,732 $ 1,160 First Financial's average impaired loans by class and interest income recognized by class was as follows: Three months ended March 31, 2019 March 31, 2018 (Dollars in thousands) Average Interest Average Interest Loans with no related allowance recorded Commercial & industrial $ 33,418 $ 279 $ 7,867 $ 26 Lease financing 162 0 41 0 Construction real estate 9 0 28 1 Commercial real estate 23,111 103 21,400 99 Residential real estate 16,967 86 6,503 47 Home equity 6,288 38 4,214 20 Installment 174 1 281 0 Total 80,129 507 40,334 193 Loans with an allowance recorded Commercial & industrial 2,111 43 204 0 Lease financing 0 0 0 0 Construction real estate 0 0 0 0 Commercial real estate 2,004 19 1,739 3 Residential real estate 300 2 1,051 7 Home equity 0 0 101 1 Installment 0 0 0 0 Total 4,415 64 3,095 11 Total Commercial & industrial 35,529 322 8,071 26 Lease financing 162 0 41 0 Construction real estate 9 0 28 1 Commercial real estate 25,115 122 23,139 102 Residential real estate 17,267 88 7,554 54 Home equity 6,288 38 4,315 21 Installment 174 1 281 0 Total $ 84,544 $ 571 $ 43,429 $ 204 Lease financing. The Company prospectively applied Topic 842 in the first quarter of 2019. First Financial originates both sales-type and direct financing leases, and the Company manages and reviews lease residuals in accordance with its credit policies. Sales-type lease contracts contain the ability to purchase the underlying equipment at lease maturity and profit or loss is recognized at lease commencement. Direct financing leases are generally three to five years in length and may be extended at maturity, however, early cancellation may result in a fee to the borrower. For direct financing leases, the net unearned income is deferred and amortized over the life of the lease. Income recognized in first quarter of 2019 related to the implementation of Topic 842 was insignificant. OREO. OREO consists of properties acquired by the Company primarily through the loan foreclosure or repossession process, that results in partial or total satisfaction of problem loans. Changes in OREO were as follows: Three months ended March 31, (Dollars in thousands) 2019 2018 Balance at beginning of period $ 1,401 $ 2,781 Additions Commercial & industrial 0 170 Residential real estate 504 459 Total additions 504 629 Disposals Commercial & industrial (22 ) (2,104 ) Residential real estate (161 ) (118 ) Total disposals (183 ) (2,222 ) Valuation adjustment Commercial & industrial 0 (97 ) Residential real estate (57 ) (26 ) Total valuation adjustment (57 ) (123 ) Balance at end of period $ 1,665 $ 1,065

ALLOWANCE FOR LOAN AND LEASE LO

ALLOWANCE FOR LOAN AND LEASE LOSSES	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
ALLOWANCE FOR LOAN AND LEASE LOSSES	ALLOWANCE FOR LOAN AND LEASE LOSSES Management maintains the ALLL at a level that it considers sufficient to absorb probable incurred loan and lease losses inherent in the portfolio. Management determines the adequacy of the ALLL based on historical loss experience as well as other significant factors such as composition of the portfolio, economic conditions, geographic footprint, the results of periodic internal and external evaluations of delinquent, nonaccrual and classified loans and any other adverse situations that may affect a specific borrower's ability to repay, including the timing of future payments. The ALLL is increased by provision expense and decreased by charge-offs, net of recoveries of amounts previously charged-off. First Financial's policy is to charge-off all or a portion of a loan when, in management's opinion, it is unlikely to collect the principal amount owed in full either through payments from the borrower or from the liquidation of collateral. Changes in the ALLL by loan category were as follows: Three months ended March 31, 2019 Real Estate (Dollars in thousands) Commercial and industrial Lease financing Construction Commercial Residential Home Equity Installment Credit card Total Allowance for loan and lease losses: Balance at beginning of period $ 18,746 $ 1,130 $ 3,413 $ 21,048 $ 4,964 $ 5,348 $ 362 $ 1,531 $ 56,542 Provision for loan and lease losses 13,268 343 (683 ) 493 125 185 19 333 14,083 Gross charge-offs (12,328 ) (100 ) 0 (1,214 ) (82 ) (468 ) (49 ) (341 ) (14,582 ) Recoveries 240 0 63 73 36 185 48 34 679 Total net charge-offs (12,088 ) (100 ) 63 (1,141 ) (46 ) (283 ) (1 ) (307 ) (13,903 ) Ending allowance for loan and lease losses $ 19,926 $ 1,373 $ 2,793 $ 20,400 $ 5,043 $ 5,250 $ 380 $ 1,557 $ 56,722 Three months ended March 31, 2018 Real Estate (Dollars in thousands) Commercial & industrial Lease financing Construction Commercial Residential Home equity Installment Credit card Total Allowance for loan and lease losses: Balance at beginning of period $ 17,598 $ 675 $ 3,577 $ 20,930 $ 4,683 $ 4,935 $ 307 $ 1,316 $ 54,021 Provision for loan and lease losses 889 (49 ) 690 815 114 (294 ) (49 ) 187 2,303 Loans charged off (885 ) 0 0 (2,176 ) (96 ) (242 ) (16 ) (254 ) (3,669 ) Recoveries 436 0 0 752 26 429 48 34 1,725 Total net charge-offs (449 ) 0 0 (1,424 ) (70 ) 187 32 (220 ) (1,944 ) Ending allowance for loan and lease losses $ 18,038 $ 626 $ 4,267 $ 20,321 $ 4,727 $ 4,828 $ 290 $ 1,283 $ 54,380 As of March 31, 2019 Real Estate (Dollars in thousands) Commercial & industrial Lease financing Construction Commercial Residential Home equity Installment Credit card Total Ending allowance balance attributable to loans Individually evaluated for impairment $ 738 $ 0 $ 0 $ 651 $ 31 $ 0 $ 0 $ 0 $ 1,420 Collectively evaluated for impairment 19,188 1,373 2,793 19,749 5,012 5,250 380 1,557 55,302 Ending allowance for loan and lease losses $ 19,926 $ 1,373 $ 2,793 $ 20,400 $ 5,043 $ 5,250 $ 380 $ 1,557 $ 56,722 Loans Individually evaluated for impairment $ 33,424 $ 301 $ 8 $ 25,206 $ 16,935 $ 6,225 $ 174 $ 0 $ 82,273 Collectively evaluated for impairment 2,510,003 95,272 458,105 3,776,973 958,185 790,893 90,515 46,982 8,726,928 Total loans $ 2,543,427 $ 95,573 $ 458,113 $ 3,802,179 $ 975,120 $ 797,118 $ 90,689 $ 46,982 $ 8,809,201 As of December 31, 2018 Real Estate (Dollars in thousands) Commercial & industrial Lease financing Construction Commercial Residential Home equity Installment Credit card Total Ending allowance balance attributable to loans Individually evaluated for impairment $ 667 $ 0 $ 0 $ 461 $ 32 $ 0 $ 0 $ 0 $ 1,160 Collectively evaluated for impairment 18,079 1,130 3,413 20,587 4,932 5,348 362 1,531 55,382 Ending allowance for loan and lease losses $ 18,746 $ 1,130 $ 3,413 $ 21,048 $ 4,964 $ 5,348 $ 362 $ 1,531 $ 56,542 Loans Individually evaluated for impairment $ 37,633 $ 22 $ 9 $ 25,022 $ 17,598 $ 6,351 $ 174 $ 0 $ 86,809 Collectively evaluated for impairment 2,477,028 93,393 548,926 3,729,659 938,048 810,931 93,038 46,382 8,737,405 Total loans $ 2,514,661 $ 93,415 $ 548,935 $ 3,754,681 $ 955,646 $ 817,282 $ 93,212 $ 46,382 $ 8,824,214

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill. Assets and liabilities acquired in a business combination are recorded at their estimated fair values as of the acquisition date. The excess cost of the acquisition over the fair value of net assets acquired is recorded as goodwill. Changes in the carrying amount of goodwill for the three months ended March 31, 2019 and the year ended December 31, 2018 were as follows: (Dollars in thousands) March 31, December 31, Balance at beginning of year $ 880,251 $ 204,084 Goodwill resulting from business combinations (524 ) 676,167 Balance at end of period $ 879,727 $ 880,251 During 2018, First Financial recorded additions to goodwill resulting from the merger with MSFG of $676.2 million , and in the first quarter of 2019, First Financial recorded its final adjustments to goodwill associated related to the merger. For further detail on the merger with MSFG, see Note 17 - Business Combinations. Goodwill is evaluated for impairment on an annual basis as of October 1 of each year, or whenever events or changes in circumstances indicate that the fair value of a reporting unit may be below its carrying value. First Financial performed its most recent annual impairment test as of October 1, 2018 and no impairment was indicated. As of March 31, 2019 , no events or changes in circumstances indicated that the fair value of a reporting unit was below its carrying value. Other intangible assets. As of March 31, 2019 and December 31, 2018 , First Financial had $38.6 million and $40.8 million , respectively, of other intangible assets included in Other intangibles in the Consolidated Balance Sheets, which primarily consist of core deposit intangibles. Core deposit intangibles represent the estimated fair value of acquired customer deposit relationships on the date of acquisition and are amortized on an accelerated basis over their estimated useful lives. Core deposit intangibles were $35.8 million and $37.9 million as of March 31, 2019 and December 31, 2018 , respectively. First Financial's core deposit intangibles have an estimated weighted average remaining life of 8.9 years . Amortization expense recognized on intangible assets for the three months ended March 31, 2019 and 2018 was $2.0 million and $0.3 million

LEASES LEASES

LEASES LEASES	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	LEASES A lease is defined as a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment for a period of time in exchange for consideration. First Financial is primarily the lessee in its leasing agreements, and substantially all of those agreements are for real estate property for branches, ATM locations and office space. On January 1, 2019, the Company adopted Topic 842 and all subsequent updates that modified Topic 842. For First Financial, this update primarily affected the accounting treatment for operating lease agreements in which the Company is the lessee. With the adoption of Topic 842, operating lease agreements are required to be recognized on the consolidated balance sheets as an ROU asset and a corresponding lease liability. Substantially all of the Company's leases are classified as operating leases, and therefore, were previously not recognized on the Company’s consolidated balance sheets. The Company's right to use an asset over the life of a lease is recorded as a "right of use" asset in Accrued interest and other assets on the Consolidated Balance Sheet and was $59.0 million at March 31, 2019 . Certain adjustments to the ROU asset may be required for items such as initial direct costs paid or incentives received. First Financial recorded a $64.6 million lease liability in Accrued interest and other liabilities on the Consolidated Balance Sheet at March 31, 2019 . The calculated amount of the ROU assets and lease liabilities are impacted by the length of the lease term and the discount rate used to calculate the present value of minimum lease payments. Regarding the discount rate, Topic 842 requires the use of the rate implicit in the lease whenever this rate is readily determinable. As this rate is rarely determinable, the Company utilizes its incremental borrowing rate at lease inception, on a collateralized basis, over a similar term. For operating leases existing prior to January 1, 2019, the rate for the remaining lease term as of January 1, 2019 was used. Leases with an initial term of 12 months or less are not recorded on the balance sheet and First Financial recognizes lease expense for these leases on a straight-line basis over the term of the lease. Most leases include one or more options to renew, with renewal terms that can extend the lease term from one to 20 years or more. The exercise of renewal options on operating leases is at the Company's sole discretion, and certain leases may include options to purchase the leased property. If at lease inception, the Company considers the exercising of a renewal option to be reasonably certain, the Company will include the extended term in the calculation of the ROU asset and lease liability. First Financial does not enter into lease agreements which contain material residual value guarantees or material restrictive covenants. Certain leases provide for increases in future minimum annual rental payments as defined in the lease agreements and leases generally also include real estate taxes and CAM charges in the annual rental payments. The components of lease expense were as follows: Three months ended (dollars in thousands) March 31, 2019 Operating lease cost $ 1,826 Short-term lease cost 1 Variable lease cost 597 Total operating lease cost $ 2,424 Future minimum commitments due under these lease agreements as of March 31, 2019 are as follows: (dollars in thousands) Operating leases 2019 (remaining nine months) $ 5,361 2020 7,070 2021 6,569 2022 6,238 2023 6,248 Thereafter 54,378 Total lease payments 85,864 Less imputed interest 21,255 Total $ 64,609 The lease term and discount rate at March 31, 2019 were as follows: Operating leases Weighted-average remaining lease term (years) 15.9 Weighted-average discount rate 3.5 % Supplemental cash information at March 31, 2019 related to leases was as follows: Three months ended (dollars in thousands) March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,823 ROU assets obtained in exchange for lease obligations Operating leases 60,249

BORROWINGS

BORROWINGS	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
BORROWINGS	BORROWINGS Short-term borrowings on the Consolidated Balance Sheets include repurchase agreements utilized for corporate sweep accounts with cash management account agreements in place, overnight advances from the FHLB and a short-term line of credit. All repurchase agreements are subject to terms and conditions agreed to by the Bank and the client. To secure its liability to the client, the Bank is authorized to sell or repurchase U.S. Treasury, government agency and mortgage-backed securities. The following shows the remaining contractual maturity of repurchase agreements by collateral pledged: (Dollars in thousands) Overnight and continuous Repurchase agreements Mortgage-backed securities $ 15,243 Collateralized mortgage obligations 79,772 Total $ 95,015 Securities sold under agreements to repurchase are secured by securities with a carrying amount of $95.5 million and $85.5 million , as of March 31, 2019 and December 31, 2018 , respectively. First Financial had $952.4 million in short-term borrowings with the FHLB of at March 31, 2019 and $857.1 million as of December 31, 2018 . These short-term borrowings are used to manage normal liquidity needs and support the Company's asset and liability management strategies. First Financial has a $30.0 million short-term credit facility with an unaffiliated bank that matures in September 2019. This facility can have a variable or fixed interest rate and provides First Financial additional liquidity, if needed, for various corporate activities including the repurchase of First Financial common stock and the payment of dividends to shareholders. As of March 31, 2019 and December 31, 2018 , there was no outstanding balance. The credit agreement requires First Financial to comply with certain covenants including those related to asset quality and capital levels, and First Financial was in compliance with all covenants associated with this facility as of March 31, 2019 and December 31, 2018 . First Financial had $546.4 million and $570.7 million of long-term debt as of March 31, 2019 and December 31, 2018, respectively, which included subordinated notes, FHLB long term advances and an interest free loan with a municipality. The following is a summary of First Financial's long-term debt: March 31, 2019 December 31, 2018 (Dollars in thousands) Amount Average rate Amount Average rate Subordinated notes $ 170,654 5.21 % $ 170,550 5.28 % Unamortized debt issuance costs (1,140 ) N/A (1,185 ) N/A FHLB borrowings 376,134 2.14 % 400,599 2.08 % Capital loan with municipality 775 0.00 % 775 0.00 % Total long-term debt $ 546,423 3.10 % $ 570,739 3.04 % In 2015, First Financial issued $120.0 million of subordinated notes, which have a fixed interest rate of 5.125% payable semiannually and mature in August 2025. These notes are not redeemable by the Company, or callable by the holders of the notes prior to maturity. In addition, First Financial acquired $49.5 million of variable rate subordinated notes in the MSFG merger that were issued to previously formed trusts in exchange for the trust proceeds. Interest on the acquired subordinated notes is payable quarterly, in arrears, and the Company has the option to defer interest payments for a period not to exceed 20 consecutive quarters. The acquired subordinated notes mature 30 years after the date of original issuance and may be called at par following the 5 year anniversary of issuance. First Financial also acquired $8.4 million of 7.40% fixed rate private placement subordinated debt in conjunction with the MSFG merger that was issued in 2015 and matures in 2025. These notes are redeemable by the Company at par following the 5 year anniversary of issuance. The subordinated notes are treated as Tier 2 capital for regulatory capital purposes and are included in Long-term debt on the Consolidated Balance Sheets. In addition to subordinated notes, long-term debt included $376.1 million and $400.6 million of fixed rate FHLB long-term advances as of March 31, 2019 and December 31, 2018 , respectively. As of March 31, 2019 , long-term FHLB advances had a weighted average interest rate of 2.14%

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Shareholders’ equity is affected by transactions and valuations of asset and liability positions that require adjustments to accumulated other comprehensive income (loss). The related tax effects allocated to other comprehensive income and reclassifications out of accumulated other comprehensive income (loss) are as follows: Three months ended March 31, 2019 Total other comprehensive income Total accumulated other comprehensive income (loss) (Dollars in thousands) Prior to Reclass Pre-tax Tax effect Net of tax Beginning balance Net activity Cumulative effect of new standard Ending balance Unrealized gain (loss) on debt securities $ 29,725 $ (178 ) $ 29,903 $ (6,398 ) $ 23,505 $ (11,601 ) $ 23,505 $ 906 $ 12,810 Unrealized gain (loss) on derivatives 93 0 93 (21 ) 72 (217 ) 72 0 (145 ) Retirement obligation 0 (375 ) 375 (85 ) 290 (32,590 ) 290 0 (32,300 ) Total $ 29,818 $ (553 ) $ 30,371 $ (6,504 ) $ 23,867 $ (44,408 ) $ 23,867 $ 906 $ (19,635 ) Three months ended March 31, 2018 Total other comprehensive income Total accumulated other comprehensive income (loss) (Dollars in thousands) Prior to Reclass Pre-tax Tax effect Net of tax Beginning balance Net activity Cumulative effect of new standard Ending balance Unrealized gain (loss) on debt securities $ (12,536 ) $ 0 $ (12,536 ) $ 2,706 $ (9,830 ) $ (182 ) $ (9,830 ) $ (190 ) $ (10,202 ) Unrealized gain (loss) on derivatives 202 0 202 (46 ) 156 (577 ) 156 (124 ) (545 ) Retirement obligation 0 (419 ) 419 (96 ) 323 (19,631 ) 323 (4,779 ) (24,087 ) Total $ (12,334 ) $ (419 ) $ (11,915 ) $ 2,564 $ (9,351 ) $ (20,390 ) $ (9,351 ) $ (5,093 ) $ (34,834 ) The following table presents the activity reclassified from accumulated other comprehensive income into income during the three month periods ended March 31, 2019 and 2018 , respectively: Amount reclassified from (1) Three months ended March 31, (Dollars in thousands) 2019 2018 Affected Line Item in the Consolidated Statements of Income Realized gain (loss) on securities available-for-sale $ (178 ) $ 0 Net gain (loss) on sales of investments securities Defined benefit pension plan Amortization of prior service cost (2) 100 103 Other noninterest expense Recognized net actuarial loss (2) (475 ) (522 ) Other noninterest expense Defined benefit pension plan total (375 ) (419 ) Total reclassifications for the period, before tax $ (553 ) $ (419 ) (1) Negative amounts are reductions to net income. (2)

DERIVATIVES

DERIVATIVES	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES	DERIVATIVES First Financial uses certain derivative instruments, including interest rate caps, floors and swaps, to meet the needs of its clients while managing the interest rate risk associated with certain transactions. First Financial does not use derivatives for speculative purposes. First Financial primarily utilizes interest rate swaps as a means to offer borrowers credit-based products that meet their needs. First Financial may also utilize interest rate swaps to manage the interest rate risk profile of the Company. Interest rate payments are exchanged with counterparties based on the notional amount established in the interest rate agreement. As only interest rate payments are exchanged, the cash requirements and credit risk associated with interest rate swaps are significantly less than the notional amount and the Company’s credit risk exposure is limited to the market value of the instruments. First Financial manages market value credit risk through counterparty credit policies, which require the Company to maintain a total derivative notional position of less than 35% of assets, total credit exposure of less than 3% of capital and no single counterparty credit risk exposure greater than $20.0 million . The Company is currently below all single counterparty and portfolio limits. Client Derivatives. First Financial utilizes interest rate swaps as a means to offer commercial borrowers fixed rate funding while providing the Company with floating rate assets. The following table details the classification and amounts recognized in the Consolidated Balance Sheets for client derivatives: March 31, 2019 December 31, 2018 Estimated fair value Estimated fair value (Dollars in thousands) Balance sheet classification Notional amount Gain Loss Notional amount Gain Loss Client derivatives - instruments associated with loans Matched interest rate swaps with borrower Accrued interest and other assets $ 1,406,914 $ 33,221 $ (5,580 ) $ 1,359,990 $ 17,402 $ (11,787 ) Matched interest rate swaps with counterparty Accrued interest and other liabilities 1,406,914 5,580 (33,228 ) 1,359,990 11,787 (17,401 ) Total $ 2,813,828 $ 38,801 $ (38,808 ) $ 2,719,980 $ 29,189 $ (29,188 ) At March 31, 2019 , the Company had a total counterparty notional amount outstanding of $1.4 billion , spread among thirteen counterparties, with an outstanding liability from these contracts of $27.1 million . At December 31, 2018 , the Company had a total counterparty notional amount outstanding of $1.4 billion , spread among thirteen counterparties, with an outstanding liability from these contracts of $4.9 million . First Financial monitors its derivative credit exposure to borrowers by monitoring the creditworthiness of the related loan customers through the Company's normal credit review processes. Additionally, the Company's ALLL Committee monitors derivative credit risk exposure related to problem loans through the Company's ALLL committee. First Financial considers the market value of a derivative instrument to be part of the carrying value of the related loan for these purposes as the borrower is contractually obligated to pay First Financial this amount in the event the derivative contract is terminated. In connection with its use of derivative instruments, First Financial and its counterparties may be required to post cash collateral to offset the market position of the derivative instruments. First Financial maintains the right to offset these derivative positions with the collateral posted against them by or with the relevant counterparties. First Financial classifies the derivative cash collateral outstanding with its counterparties as an adjustment to the fair value of the derivative contracts within Accrued interest and other assets or Accrued interest and other liabilities in the Consolidated Balance Sheets. The following table discloses the gross and net amounts of client derivative liabilities recognized in the Consolidated Balance Sheets: March 31, 2019 December 31, 2018 (Dollars in thousands) Gross amounts of recognized liabilities Gross amounts offset in the Consolidated Balance Sheets Net amounts of liabilities presented in the Consolidated Balance Sheets Gross amounts of recognized liabilities Gross amounts offset in the Consolidated Balance Sheets Net amounts of liabilities presented in the Consolidated Balance Sheets Client derivatives Matched interest rate swaps with counterparty $ 38,808 $ (36,980 ) $ 1,828 $ 29,189 $ (14,577 ) $ 14,612 The following table details the derivative financial instruments, the average remaining maturities and the weighted-average interest rates being paid and received by First Financial at March 31, 2019 : Weighted-average rate (Dollars in thousands) Notional amount Average maturity (years) Fair value Receive Pay Client derivatives Receive fixed, matched interest rate swaps with borrower $ 1,406,914 6.1 $ 27,641 4.70 % 4.80 % Pay fixed, matched interest rate swaps with counterparty 1,406,914 6.1 (27,648 ) 4.80 % 4.70 % Total client derivatives $ 2,813,828 6.1 $ (7 ) 4.75 % 4.75 % Credit Derivatives. In conjunction with participating interests in commercial loans, First Financial periodically enters into risk participation agreements with counterparties whereby First Financial assumes a portion of the credit exposure associated with an interest rate swap on the participated loan in exchange for a fee. Under these agreements, First Financial will make payments to the counterparty if the loan customer defaults on its obligation to perform under the interest rate swap contract with the counterparty. The total notional value of these agreements totaled $119.8 million as of March 31, 2019 and $138.4 million as of December 31, 2018 . The fair value of these agreements is recorded in Accrued interest and other liabilities on the Consolidated Balance Sheets and was $0.1 million at both March 31, 2019 and December 31, 2018 . Mortgage Derivatives. First Financial enters into IRLCs and forward commitments for the future delivery of mortgage loans to third party investors, which are considered derivatives. When borrowers secure an IRLC with First Financial and the loan is intended to be sold, First Financial will enter into forward commitments for the future delivery of the loans to third party investors in order to hedge against the effect of changes in interest rates impacting IRLCs and loans held for sale. At March 31, 2019 , the notional amount of the IRLCs was $32.8 million and the notional amount of forward commitments was $32.8 million . As of December 31, 2018 , the notional amount of IRLCs was $20.8 million and the notional amount of forward commitments was $12.3 million . The fair value of these agreements was $0.1 million at March 31, 2019 and insignificant at December 31, 2018

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES First Financial offers a variety of financial instruments including letters of credit and outstanding commitments to extend credit to assist clients in meeting their requirement for liquidity and credit enhancement. GAAP does not require these financial instruments to be recorded in the Consolidated Financial Statements. First Financial utilizes the same credit policies in issuing commitments and conditional obligations as it does for credit instruments recorded on the Consolidated Balance Sheets. First Financial’s exposure to credit loss in the event of non-performance by the counterparty is represented by the contractual amounts of those instruments. First Financial utilizes the ALLL methodology to maintain a reserve that it considers sufficient to absorb probable incurred losses incurred in letters of credit and outstanding loan commitments. First Financial had $0.8 million and $0.7 million of reserves for unfunded commitments recorded in Accrued interest and other liabilities on the Consolidated Balance Sheets as of March 31, 2019 and December 31, 2018 , respectively. Loan commitments. Loan commitments are agreements to extend credit to a client, absent any violation of conditions established in the commitment agreement. 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 expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The amount of collateral obtained, if deemed necessary by First Financial upon extension of credit, is based on management’s credit evaluation of the client. The collateral held varies, but may include securities, real estate, inventory, plant or equipment. First Financial had commitments outstanding to extend credit totaling $3.1 billion and $3.0 billion at March 31, 2019 and December 31, 2018 , respectively. As of March 31, 2019 , loan commitments with a fixed interest rate totaled $182.5 million while commitments with variable interest rates totaled $2.9 billion . At December 31, 2018 , loan commitments with a fixed interest rate totaled $174.0 million while commitments with variable interest rates totaled $2.9 billion . First Financial's fixed rate loan commitments have interest rates ranging from 0.00% to 21.00% and maturities ranging from less than 1 year to 30 years for both March 31, 2019 and December 31, 2018 . Letters of credit. Letters of credit are conditional commitments issued by First Financial to guarantee the performance of a client to a third party. First Financial’s letters of credit consist of performance assurances made on behalf of clients who have a contractual commitment to produce or deliver goods or services. The risk to First Financial arises from its obligation to make payment in the event of the client's contractual default to produce the contracted good or service to a third party. First Financial issued letters of credit aggregating $33.4 million and $32.7 million at March 31, 2019 and December 31, 2018 , respectively. Management conducts regular reviews of these instruments on an individual client basis. Investments in affordable housing tax credits. First Financial has made investments in certain qualified affordable housing tax credits. These credits are an indirect federal subsidy that provide tax incentives to encourage investment in the development, acquisition and rehabilitation of affordable rental housing, and allow investors to claim tax credits and other tax benefits (such as deductions from taxable income for operating losses) on their federal income tax returns. The principal risk associated with qualified affordable housing investments is the potential for noncompliance with the tax code requirements, such as failure to rent property to qualified tenants, resulting in the unavailability or recapture of the tax credits and other tax benefits. Investments in affordable housing projects are accounted for under the proportional amortization method and are included in Accrued interest and other assets in the Consolidated Balance Sheets. First Financial's affordable housing commitments totaled $36.2 million and $39.4 million as of March 31, 2019 and December 31, 2018 , respectively. The Company recognized tax credits of $1.6 million and $1.1 million for the three months ended March 31, 2019 and 2018 , respectively. The Company recognized amortization expense which was included in income tax expense of $1.6 million and $1.3 million for the three months ended March 31, 2019 and 2018 , respectively. First Financial had no affordable housing contingent commitments as of March 31, 2019 or December 31, 2018 . Investments in historic tax credits. First Financial has noncontrolling financial investments in private investment funds and partnerships which are not consolidated. These investments may generate a return through the realization of federal and state income tax credits, as well as other tax benefits, such as tax deductions from net operating losses of the investments over a period of time. Investments in historic tax credits are accounted for under the equity method of accounting and are carried in Accrued interest and other assets on the Consolidated Balance Sheets. The Company’s recorded investment in these entities was approximately $3.7 million at March 31, 2019 and $3.9 million at December 31, 2018 . The maximum exposure to loss related to these investments was $3.7 million at March 31, 2019 and $3.9 million at December 31, 2018 , representing the Company’s investment balance and its unfunded commitments to invest additional amounts. Investments in historic tax credits resulted in insignificant tax credits for the three months ended March 31, 2019 and $0.1 million for the three months ended March 31, 2018 . Contingencies/Litigation. First Financial and its subsidiaries are engaged in various matters of litigation from time to time, and have a number of unresolved claims pending. Additionally, as part of the ordinary course of business, First Financial and its subsidiaries are parties to litigation involving claims to the ownership of funds in particular accounts, the collection of delinquent accounts, challenges to security interests in collateral and foreclosure interests that are incidental to our regular business activities. While the ultimate liability with respect to these litigation matters and claims cannot be determined at this time, First Financial believes that damages, if any, and other amounts relating to pending matters are not probable or cannot be reasonably estimated as of March 31, 2019 . Reserves are established for these various matters of litigation, when appropriate, under FASB ASC Topic 450, Contingencies, based in part upon the advice of legal counsel. First Financial had no reserves related to litigation matters as of March 31, 2019 or December 31, 2018

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES For the first quarter 2019 , income tax expense was $9.9 million , resulting in an effective tax rate of 17.8% compared with income tax expense of $7.7 million and an effective tax rate of 20.1% for the comparable period in 2018. The decrease in the effective tax rate is primarily due to favorable resolution of a state uncertain tax position, favorable tax reform guidance related to the treatment of acquired bank owned life insurance and stock compensation activity. At both March 31, 2019 and December 31, 2018 , First Financial had $2.4 million and $2.9 million , respectively, of unrecognized tax benefits, as determined in FASB ASC Topic 740-10, Income Taxes, that if recognized would favorably affect the effective income tax rate in future periods. The unrecognized tax benefits relate to state income tax exposures from taking tax positions where the Company believes it is likely that, upon examination, a state may take a position contrary to the position taken by First Financial. The Company believes that resolution regarding our uncertain tax positions is reasonably possible within the next twelve months and could result in full, partial or no recognition of the benefit. First Financial recognizes interest accrued related to unrecognized tax benefits and penalties as income tax expense. At March 31, 2019 and December 31, 2018 , the Company had no interest or penalties recorded. First Financial and its subsidiaries are subject to U.S. federal income tax as well as state and local income tax in several jurisdictions. Tax years prior to 2014 have been closed and are no longer subject to U.S. federal income tax examinations. Tax years 2014 through 2018 remain open to examination by the federal taxing authority.

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS First Financial sponsors a non-contributory defined benefit pension plan covering substantially all employees and uses a December 31 measurement date for the plan. Plan assets were primarily invested in fixed income and publicly traded equity mutual funds. The pension plan does not directly own any shares of First Financial common stock or any other First Financial security or product. First Financial made no cash contributions to fund the pension plan during the three months ended March 31, 2019 , or the year ended December 31, 2018, and does not expect to make cash contributions to the plan through the remainder of 2019. As a result of the plan’s actuarial projections, which included consideration of the impact of the merger with MSFG, First Financial recorded expense of $0.4 million for the three months ended March 31, 2019 . Conversely, First Financial recorded income of $0.2 million for the three months ended March 31, 2018 . The following table sets forth information concerning amounts recognized in First Financial’s Consolidated Statements of Income related to the Company's pension plan: Three months ended March 31, (Dollars in thousands) 2019 2018 Service cost $ 1,750 $ 1,295 Interest cost 700 590 Expected return on assets (2,450 ) (2,460 ) Amortization of prior service cost (100 ) (103 ) Net actuarial loss 475 522 Net periodic benefit cost (income) $ 375 $ (156 )

REVENUE RECOGNITION

REVENUE RECOGNITION	3 Months Ended
	Mar. 31, 2019
Revenue Recognition [Abstract]
REVENUE RECOGNITION	REVENUE RECOGNITION The majority of the Company's revenues come from interest income and other sources, including loans, leases, securities and derivatives, that are outside the scope of ASU No. 2014-09, Revenue from Contracts with Customers. The Company's services that fall within the scope of ASU 2019-09 are presented within Noninterest income and are recognized as revenue as the Company satisfies its obligation to the customer. Services within the scope of this guidance include service charges on deposits, trust and wealth management fees, bankcard income, gain/loss on the sale of OREO and investment brokerage fees. Service charges on deposit accounts. The Company earns fees from its deposit customers for transaction-based, account maintenance and overdraft services. Transaction-based fees, which include services such as ATM use fees, stop payment charges, statement rendering and ACH fees, are recognized at the time the transaction is executed as that is the point in time the Company fulfills the customer's request. Account maintenance fees, which relate primarily to monthly maintenance, are earned over the course of a month, representing the period over which the Company satisfies the performance obligation. Similarly, overdraft fees are recognized at the point in time that the overdraft occurs as this corresponds with the Company's performance obligation. Service charges on deposit accounts are withdrawn from the customer's account balance. Trust and wealth management fees. Trust and wealth management fees are primarily asset-based, but can also include flat fees based upon a specific service rendered, such as tax preparation services. The Company’s performance obligation is generally satisfied over time and the resulting fees are recognized monthly, based upon the month-end market value of the assets under management and the applicable fees. The Company does not earn performance-based incentives. Optional services such as real estate sales and tax return preparation services are also available to existing trust and wealth management customers. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, as incurred. Bankcard income. The Company earns interchange fees from cardholder transactions conducted through the Visa payment network. Interchange fees from cardholder transactions represent a percentage of the underlying transaction value and are recognized concurrent with the transaction processing services provided to the cardholder. Interchange income is presented on the Consolidated Statements of Income net of expenses. Gross interchange income for the first three months of 2019 was $8.5 million , which was partially offset by $2.9 million of expenses within Noninterest income. Gross interchange income for the first three months of 2018 was $5.4 million , which was partially offset by $2.0 million of expenses. Other. Other noninterest income consists of other recurring revenue streams such as transaction fees, safe deposit rental income, insurance commissions, merchant referral income, gain (loss) on sale of OREO and brokerage revenue. Transaction fees primarily include check printing sales commissions, collection fees and wire transfer fees which arise from in-branch transactions. Safe deposit rental income arises from services charged to the customer on an annual basis and recognized upon receipt of payment. Insurance commissions are agent commissions earned by the Company and earned upon the effective date of the bound coverage. Merchant referral income is associated with a program whereby the Company receives a share of processing revenue that is generated from clients that were referred by First Financial to the service provider. Revenue is recognized at the point in time when the transaction occurs. The Company records a gain or loss from the sale of OREO when control of the property transfers to the buyer, which generally occurs at the time of the executed deed. When the Company finances the sale of OREO to the buyer, the Company assesses whether the buyer is committed to perform their obligations under the contract and whether collectibility of the transaction price is probable. Once these criteria are met, the OREO asset is derecognized and the gain or loss on sale is recorded upon the transfer of control of the property to the buyer. Brokerage revenue represents fees from investment brokerage services provided to customers by a third party provider. The Company receives commissions from the third-party service provider on a monthly basis based upon customer activity for the month. The fees are recognized monthly and a receivable is recorded until commissions are paid the following month. Because the Company (i) acts as an agent in arranging the relationship between the customer and the third-party service provider and (ii) does not control the services rendered to the customers, investment brokerage fees are presented net of related costs.

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	EARNINGS PER COMMON SHARE The following table sets forth the computation of basic and diluted earnings per share: Three months ended March 31, (Dollars in thousands, except per share data) 2019 2018 Numerator Net income available to common shareholders $ 45,839 $ 30,506 Denominator Basic earnings per common share - weighted average shares 97,926,088 61,654,686 Effect of dilutive securities Employee stock awards 510,223 464,254 Warrants 0 61,804 Diluted earnings per common share - adjusted weighted average shares 98,436,311 62,180,744 Earnings per share available to common shareholders Basic $ 0.47 $ 0.49 Diluted $ 0.47 $ 0.49 First Financial had no warrants outstanding to purchase the Company's common stock as of March 31, 2019 . Warrants acquired in the MSFG merger were outstanding as of December 31, 2018 and were exercised in January 2019. At March 31, 2018, First Financial had warrants outstanding representing the right to purchase 101,808 shares of common stock at an exercise price of $12.11 per share and all unexercised warrants expired in December 2018. Stock options and warrants with exercise prices greater than the average market price of the common shares were not included in the computation of net income per diluted share, as they would have been antidilutive. Using the end of period price of the Company's common shares, there were no antidilutive options at March 31, 2019 and March 31, 2018

FAIR VALUE DISCLOSURES

FAIR VALUE DISCLOSURES	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE DISCLOSURES	FAIR VALUE DISCLOSURES The fair value framework as disclosed in the Fair Value Topic includes a hierarchy which focuses on prioritizing the inputs used in valuation techniques. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1), a lower priority to observable inputs other than quoted prices in active markets for identical assets and liabilities (Level 2) and the lowest priority to unobservable inputs (Level 3). When determining the fair value measurements for assets and liabilities, First Financial looks to active markets to price identical assets or liabilities whenever possible and classifies such items in Level 1. When identical assets and liabilities are not traded in active markets, First Financial looks to observable market data for similar assets and liabilities and classifies such items as Level 2. Certain assets and liabilities are not actively traded in observable markets and First Financial must use alternative techniques, based on unobservable inputs, to determine the fair value and classifies such items as Level 3. The level within the fair value hierarchy is based on the lowest level of input that is significant in the fair value measurement. The estimated fair values of First Financial’s financial instruments not measured at fair value on a recurring or nonrecurring basis in the consolidated financial statements were as follows: Carrying Estimated fair value (Dollars in thousands) value Total Level 1 Level 2 Level 3 March 31, 2019 Financial assets Cash and short-term investments $ 219,228 $ 219,228 $ 219,228 $ 0 $ 0 Investment securities held-to-maturity 158,305 153,075 0 153,075 0 Other investments 115,731 N/A N/A N/A N/A Loans held for sale 8,217 8,217 0 8,217 0 Loans and leases 8,752,479 8,651,343 0 0 8,651,343 Accrued interest receivable 44,171 44,171 0 14,230 29,941 Financial liabilities Deposits 10,133,897 10,117,317 0 10,117,317 0 Short-term borrowings 1,047,415 1,047,415 1,047,415 0 0 Long-term debt 546,423 538,743 0 538,743 0 Accrued interest payable 12,449 12,449 2,907 9,542 0 Carrying Estimated fair value (Dollars in thousands) value Total Level 1 Level 2 Level 3 December 31, 2018 Financial assets Cash and short-term investments $ 273,959 $ 273,959 $ 273,959 $ 0 $ 0 Investment securities held-to-maturity 429,328 424,118 0 424,118 0 Other investments 115,660 N/A N/A N/A N/A Loans held for sale 4,372 4,372 0 4,372 0 Loans and leases 8,767,672 8,662,868 0 0 8,662,868 Accrued interest receivable 41,816 41,816 0 13,819 27,997 Financial liabilities Deposits 10,140,394 10,113,475 0 10,113,475 0 Short-term borrowings 1,040,691 1,040,691 1,040,691 0 0 Long-term debt 570,739 557,933 0 557,933 0 Accrued interest payable 12,126 12,126 2,035 10,091 0 In accordance with our adoption of ASU 2016-01 in 2018, the methods utilized to measure the fair value of financial instruments at March 31, 2019 and December 31, 2018 represent an approximation of exit price, however, an actual exit price may differ. The following methods, assumptions and valuation techniques were used by First Financial to measure different financial assets and liabilities at fair value on a recurring or nonrecurring basis. Investment securities. Investment securities classified as available-for-sale are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted market prices, when available (Level 1). If quoted market prices are not available, fair values are measured utilizing independent valuation techniques of identical or similar investment securities. First Financial compiles prices from various sources who may apply such techniques as matrix pricing to determine the value of identical or similar investment securities (Level 2). Matrix pricing is a mathematical technique widely used in the banking industry to value investment securities without relying exclusively on quoted prices for the specific investment securities but rather relying on the investment securities’ relationship to other benchmark quoted investment securities. Any investment securities not valued based upon the methods previously described are considered Level 3. First Financial utilizes values provided by third-party pricing vendors to price the investment securities portfolio in accordance with the fair value hierarchy of the Fair Value Topic and reviews the pricing methodologies utilized by the pricing vendors to ensure that the fair value determination is consistent with the applicable accounting guidance. First Financial’s pricing process includes a series of quality assurance activities where prices are compared to recent market conditions, historical prices and other independent pricing services. Further, the Company periodically validates the fair value of a sample of securities in the portfolio by comparing the fair values to prices from other independent sources for the same or similar securities. First Financial analyzes unusual or significant variances, conducts additional research with the pricing vendor, and if necessary, takes appropriate action based on its findings. The results of the quality assurance process are incorporated into the selection of pricing providers by the portfolio manager. Impaired loans. The fair value of impaired loans are specifically reviewed for purposes of determining the appropriate amount of impairment to be allocated to the ALLL. Fair value is generally measured based on the value of the collateral securing the loans. Collateral may be in the form of real estate or business assets including equipment, inventory and accounts receivable. The value of real estate collateral is determined utilizing an income or market valuation approach based on an appraisal conducted by an independent, licensed third-party appraiser (Level 3). The value of business equipment is based on an outside appraisal, if deemed significant, or the net book value on the applicable borrower financial statements. Likewise, values for inventory and accounts receivable collateral are based on borrower financial statement balances or aging reports on a discounted basis as appropriate (Level 3). Impaired loans are measured at fair value on a nonrecurring basis. Any fair value adjustments are recorded in the period incurred as provision for loan and lease losses on the Consolidated Statements of Income. OREO. Assets acquired through loan foreclosure are recorded at fair value less costs to sell, with any difference between the fair value of the property and the carrying value of the loan recorded as a charge-off. If the fair value is higher than the carrying amount of the loan, the excess is recognized first as a recovery and then as noninterest income. Subsequent changes in value are reported as adjustments to the carrying amount and are recorded in noninterest expense. The carrying value of OREO is not re-measured to fair value on a recurring basis, but is subject to fair value adjustments when the carrying value differs from the fair value, less estimated selling costs. Fair value is based on recent real estate appraisals and is updated at least annually. The Company classifies OREO in level 3 of the fair value hierarchy. Derivatives. The fair values of derivative instruments are based primarily on a net present value calculation of the cash flows related to the interest rate swaps at the reporting date, using primarily observable market inputs such as interest rate yield curves which represents the cost to terminate the swap if First Financial should choose to do so. Additionally, First Financial utilizes an internally-developed model to value the credit risk component of derivative assets and liabilities, which is recorded as an adjustment to the fair value of the derivative asset or liability on the reporting date. Derivative instruments are classified as Level 2 in the fair value hierarchy. The financial assets and liabilities measured at fair value on a recurring basis in the consolidated financial statements were as follows: Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 Assets/liabilities at fair value March 31, 2019 Assets Derivatives $ 0 $ 39,062 $ 0 $ 39,062 Investment securities available-for-sale 98 3,100,358 13,355 3,113,811 Total $ 98 $ 3,139,420 $ 13,355 $ 3,152,873 Liabilities Derivatives $ 0 $ 38,985 $ 0 $ 38,985 Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 Assets/liabilities at fair value December 31, 2018 Assets Derivatives $ 0 $ 29,543 $ 0 $ 29,543 Investment securities available-for-sale 97 2,764,443 14,715 2,779,255 Total $ 97 $ 2,793,986 $ 14,715 $ 2,808,798 Liabilities Derivatives $ 0 $ 29,336 $ 0 $ 29,336 The following table presents a reconciliation for certain AFS securities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the three months ended March 31, 2019 . No AFS securities were measured at fair value on a recurring basis for the three months ended March 31, 2018. Three months ended (dollars in thousands) March 31, 2019 Beginning balance $ 14,715 Accretion (amortization) 7 Increase (decrease) in fair value 21 Settlements (1,388 ) Ending balance $ 13,355 Certain financial assets and liabilities are measured at fair value on a nonrecurring basis. Adjustments to the fair market value of these assets usually result from the application of fair value accounting or write-downs of individual assets. The following table summarizes financial assets and liabilities measured at fair value on a nonrecurring basis. Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 March 31, 2019 Assets Impaired loans $ 0 $ 0 $ 4,391 OREO 0 0 1,046 Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 December 31, 2018 Assets Impaired loans $ 0 $ 0 $ 1,320 OREO 0 0 1,089

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS On April 1, 2018, the Company completed its acquisition of MainSource Financial Group, Inc. and its banking subsidiary, MainSource Bank. Therefore, results of MSFG have been included in the results of operations beginning on April 1, 2018. Under the terms of the merger agreement, shareholders of MSFG received 1.3875 common shares of First Financial common stock for each share of MSFG common stock, with cash paid in lieu of fractional shares. Including outstanding options and warrants to purchase MSFG common stock, the total purchase consideration was $1.1 billion and resulted in goodwill of $675.6 million . The goodwill arising from the acquisition largely reflected synergies and cost savings resulting from combining the operations of the companies. First Financial incurred merger related expenses related to the acquisition of MSFG of $1.7 million for the first quarter of 2019 and $37.8 million during the year ended December 31, 2018. The acquisition provides additional revenue growth and diversification. The goodwill is not deductible for income tax purposes as the transaction was accounted for as a tax-free exchange. For further detail, see Note 6 – Goodwill and Other Intangible Assets. The MainSource transaction was accounted for using the acquisition method of accounting and accordingly, assets acquired, liabilities assumed and consideration exchanged were recorded at estimated fair value on the acquisition date, in accordance with FASB ASC Topic 805, Business Combinations. The fair value measurements of assets acquired and liabilities assumed were subject to refinement for up to one year after the closing date of the acquisition as additional information relative to closing date fair values became available. The fair values of assets acquired and liabilities assumed are considered final as of March 31, 2019. The following table provides the purchase price calculation as of the acquisition date, identifiable assets purchased and liabilities assumed at their estimated fair value. As a condition of the merger, certain acquired assets and liabilities held for sale were divested subsequent to the closing of the merger. There was no gain or loss recorded in the Consolidated Statement of Income in conjunction with this divestiture. (Dollars in thousands) MainSource Purchase consideration Cash consideration $ 43 Stock consideration 1,043,424 Warrant consideration 14,460 Options consideration 1,577 Total purchase consideration 1,059,504 Assets acquired Cash 71,806 Investment securities available-for-sale 900,935 Investment securities held-to-maturity 171,423 Other investments 28,763 Loans 2,792,572 Premises and equipment 98,814 Intangible assets 42,887 Other assets 167,829 Assets held for sale 127,775 Total assets acquired 4,402,804 Liabilities assumed Deposits 3,263,920 Subordinated notes 49,027 FHLB advances 291,887 Other borrowings 205,620 Other liabilities 32,649 Liabilities held for sale 175,840 Total liabilities assumed 4,018,943 Net identifiable assets 383,861 Goodwill $ 675,643 The fair value of net assets acquired includes fair value adjustments to certain loans that were not considered impaired as of the acquisition date as the Company believes that all contractual cash flows will be collected. The fair value adjustments were determined using discounted cash flows. In conjunction with the MSFG merger, First Financial acquired non-impaired loans with a fair value and gross contractual amounts receivable of $2.8 billion and $2.9 billion on the date of acquisition. The following table presents supplemental pro forma information as if the MSFG acquisition had occurred at the beginning of 2017. The pro forma information includes adjustments for interest income on acquired loans, amortization of intangible assets arising from the transaction, depreciation expense on property acquired, interest expense on deposits acquired, merger-related expenses incurred and the related income tax effects. The pro forma financial information is not necessarily indicative of the results of operations that would have occurred had the transactions been effected on the assumed date. The disclosures regarding the results of operations for MSFG subsequent to its acquisition date are omitted as this information is not practical to obtain. Twelve months ended December 31, (Dollars in thousands, except per share data) 2018 2017 Pro Forma Condensed Combined Income Statement Information Net interest income $ 484,915 $ 454,579 Net income 221,122 130,402 Basic earnings per share 2.27 1.34 Diluted earnings per share 2.25 1.33

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2019
Off-Balance-Sheet Credit Exposure, Policy [Policy Text Block]	Letters of credit are conditional commitments issued by First Financial to guarantee the performance of a client to a third party.  First Financial’s letters of credit consist of performance assurances made on behalf of clients who have a contractual commitment to produce or deliver goods or services.  The risk to First Financial arises from its obligation to make payment in the event of the client's contractual default to produce the contracted good or service to a third party.
Basis of Presentation Policy	The Consolidated Financial Statements of First Financial Bancorp., a financial holding company principally serving Ohio, Indiana, Kentucky and Illinois, include the accounts and operations of First Financial and its wholly-owned subsidiary, First Financial Bank. All significant intercompany transactions and accounts have been eliminated in consolidation.  Certain reclassifications of prior periods' amounts have been made to conform to current year presentation. Such reclassifications had no effect on net earnings.
Use of Estimates, Policy	The preparation of financial statements in conformity with GAAP requires management to make estimates, assumptions and judgments that affect the amounts reported in the Consolidated Financial Statements and accompanying Notes. These estimates, assumptions and judgments are inherently subjective and may be susceptible to significant change. Actual realized amounts could differ materially from these estimates.
Loans and Leases Receivable, Past Due Status, Policy	Loans are considered past due or delinquent when the contractual principal or interest due in accordance with the terms of the loan agreement remains unpaid after the date of the scheduled payment.
Loans and Leases Receivable, Nonaccrual Loan and Lease Status, Policy	Loans are classified as nonaccrual when, in the opinion of management, collection of principal or interest is doubtful or when principal or interest payments are 90 days or more past due. Generally, loans are classified as nonaccrual due to the continued failure to adhere to contractual payment terms by the borrower, coupled with other pertinent factors. When a loan is classified as nonaccrual, the accrual of interest income is discontinued and previously accrued but unpaid interest is reversed. Any payments received while a loan is on nonaccrual status are applied as a reduction to the carrying value of the loan. A loan classified as nonaccrual may return to accrual status if none of the principal and interest due and unpaid, and the Bank expects repayment of the remaining contractual principal and interest. Purchased impaired loans are classified as performing, even though they may be contractually past due, as any nonpayment of contractual principal or interest is considered in the periodic re-estimation of expected cash flows and is included in the resulting recognition of current period provision for loan and lease losses or prospective yield adjustments.
Loans and Leases Receivable, Troubled Debt Restructuring Policy	A loan modification is considered a TDR when the borrower is experiencing financial difficulty and concessions are made by the Company that would not otherwise be considered for a borrower with similar credit characteristics. The most common types of modifications include interest rate reductions, maturity extensions and modifications to principal amortization, including interest-only structures. Modified terms are dependent upon the financial position and needs of the individual borrower. If the modification agreement is violated, the loan is managed by the Company’s credit administration group for resolution, which may result in foreclosure in the case of real estate.
Impaired Financing Receivable, Policy	Loans classified as nonaccrual and loans modified as TDRs are considered impaired.First Financial individually reviews all impaired commercial loan relationships, as well as consumer loan TDRs, greater than $250,000
Loans and Leases Receivable, Real Estate Acquired Through Foreclosure, Policy	OREO consists of properties acquired by the Company primarily through the loan foreclosure or repossession process, that results in partial or total satisfaction of problem loans.
Loans and Leases Receivable, Allowance for Loan Losses Policy	Management maintains the ALLL at a level that it considers sufficient to absorb probable incurred loan and lease losses inherent in the portfolio. Management determines the adequacy of the ALLL based on historical loss experience as well as other significant factors such as composition of the portfolio, economic conditions, geographic footprint, the results of periodic internal and external evaluations of delinquent, nonaccrual and classified loans and any other adverse situations that may affect a specific borrower's ability to repay, including the timing of future payments.
Goodwill and Intangible Assets, Goodwill, Policy	Assets and liabilities acquired in a business combination are recorded at their estimated fair values as of the acquisition date. The excess cost of the acquisition over the fair value of net assets acquired is recorded as goodwill.
Goodwill and Intangible Assets, Goodwill Impairment Policy	Goodwill is evaluated for impairment on an annual basis as of October 1 of each year, or whenever events or changes in circumstances indicate that the fair value of a reporting unit may be below its carrying value.
Goodwill and Intangible Assets, Policy	Core deposit intangibles represent the estimated fair value of acquired customer deposit relationships on the date of acquisition and are amortized on an accelerated basis
Income Tax, Policy	The unrecognized tax benefits relate to state income tax exposures from taking tax positions where the Company believes it is likely that, upon examination, a state may take a position contrary to the position taken by First Financial.
Commitments and Contingencies, Policy	First Financial offers a variety of financial instruments including letters of credit and outstanding commitments to extend credit to assist clients in meeting their requirement for liquidity and credit enhancement. GAAP does not require these financial instruments to be recorded in the Consolidated Financial Statements.
Fair Value Measurement, Policy [Policy Text Block]	The fair value framework as disclosed in the Fair Value Topic includes a hierarchy which focuses on prioritizing the inputs used in valuation techniques. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1), a lower priority to observable inputs other than quoted prices in active markets for identical assets and liabilities (Level 2) and the lowest priority to unobservable inputs (Level 3). When determining the fair value measurements for assets and liabilities, First Financial looks to active markets to price identical assets or liabilities whenever possible and classifies such items in Level 1. When identical assets and liabilities are not traded in active markets, First Financial looks to observable market data for similar assets and liabilities and classifies such items as Level 2. Certain assets and liabilities are not actively traded in observable markets and First Financial must use alternative techniques, based on unobservable inputs, to determine the fair value and classifies such items as Level 3. The level within the fair value hierarchy is based on the lowest level of input that is significant in the fair value measurement.
Fair Value of Financial Instruments, Policy	The following methods, assumptions and valuation techniques were used by First Financial to measure different financial assets and liabilities at fair value on a recurring or nonrecurring basis. Investment securities. Investment securities classified as available-for-sale are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted market prices, when available (Level 1). If quoted market prices are not available, fair values are measured utilizing independent valuation techniques of identical or similar investment securities. First Financial compiles prices from various sources who may apply such techniques as matrix pricing to determine the value of identical or similar investment securities (Level 2). Matrix pricing is a mathematical technique widely used in the banking industry to value investment securities without relying exclusively on quoted prices for the specific investment securities but rather relying on the investment securities’ relationship to other benchmark quoted investment securities. Any investment securities not valued based upon the methods previously described are considered Level 3. First Financial utilizes values provided by third-party pricing vendors to price the investment securities portfolio in accordance with the fair value hierarchy of the Fair Value Topic and reviews the pricing methodologies utilized by the pricing vendors to ensure that the fair value determination is consistent with the applicable accounting guidance. First Financial’s pricing process includes a series of quality assurance activities where prices are compared to recent market conditions, historical prices and other independent pricing services. Further, the Company periodically validates the fair value of a sample of securities in the portfolio by comparing the fair values to prices from other independent sources for the same or similar securities. First Financial analyzes unusual or significant variances, conducts additional research with the pricing vendor, and if necessary, takes appropriate action based on its findings. The results of the quality assurance process are incorporated into the selection of pricing providers by the portfolio manager. Impaired loans. The fair value of impaired loans are specifically reviewed for purposes of determining the appropriate amount of impairment to be allocated to the ALLL. Fair value is generally measured based on the value of the collateral securing the loans. Collateral may be in the form of real estate or business assets including equipment, inventory and accounts receivable. The value of real estate collateral is determined utilizing an income or market valuation approach based on an appraisal conducted by an independent, licensed third-party appraiser (Level 3). The value of business equipment is based on an outside appraisal, if deemed significant, or the net book value on the applicable borrower financial statements. Likewise, values for inventory and accounts receivable collateral are based on borrower financial statement balances or aging reports on a discounted basis as appropriate (Level 3). Impaired loans are measured at fair value on a nonrecurring basis. Any fair value adjustments are recorded in the period incurred as provision for loan and lease losses on the Consolidated Statements of Income. OREO. Assets acquired through loan foreclosure are recorded at fair value less costs to sell, with any difference between the fair value of the property and the carrying value of the loan recorded as a charge-off. If the fair value is higher than the carrying amount of the loan, the excess is recognized first as a recovery and then as noninterest income. Subsequent changes in value are reported as adjustments to the carrying amount and are recorded in noninterest expense. The carrying value of OREO is not re-measured to fair value on a recurring basis, but is subject to fair value adjustments when the carrying value differs from the fair value, less estimated selling costs. Fair value is based on recent real estate appraisals and is updated at least annually. The Company classifies OREO in level 3 of the fair value hierarchy. Derivatives.
Loan Commitments, Policy [Policy Text Block]	Loan commitments are agreements to extend credit to a client, absent any violation of conditions established in the commitment agreement.  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 expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements.  The amount of collateral obtained, if deemed necessary by First Financial upon extension of credit, is based on management’s credit evaluation of the client.  The collateral held varies, but may include securities, real estate, inventory, plant or equipment.
Other Contract-Mortgage
Derivatives, Methods of Accounting, Hedging Derivatives, Policy	First Financial enters into IRLCs and forward commitments for the future delivery of mortgage loans to third party investors, which are considered derivatives. When borrowers secure an IRLC with First Financial and the loan is intended to be sold, First Financial will enter into forward commitments for the future delivery of the loans to third party investors in order to hedge against the effect of changes in interest rates impacting IRLCs and loans held for sale.
Credit Risk
Derivatives, Methods of Accounting, Hedging Derivatives, Policy	First Financial manages market value credit risk through counterparty credit policies, which require the Company to maintain a total derivative notional position of less than 35% of assets, total credit exposure of less than 3% of capital and no single counterparty credit risk exposure greater than $20.0 million
Fair Value Hedges
Derivatives, Methods of Accounting, Hedging Derivatives, Policy	First Financial utilizes interest rate swaps as a means to offer commercial borrowers fixed rate funding while providing the Company with floating rate assets.

INVESTMENTS (Tables)

INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Summary of Held-To-Maturity and Available-For-Sale Investment Securities	The following is a summary of HTM and AFS investment securities as of March 31, 2019 : Held-to-maturity Available-for-sale (Dollars in thousands) Amortized Unrecognized gain Unrecognized loss Fair Amortized cost Unrealized gain Unrealized loss Fair U.S. Treasuries $ 0 $ 0 $ 0 $ 0 $ 99 $ 0 $ (1 ) $ 98 Securities of U.S. government agencies and corporations 0 0 0 0 30,880 74 (355 ) 30,599 Mortgage-backed securities - residential 24,937 72 (671 ) 24,338 557,730 4,566 (3,449 ) 558,847 Mortgage-backed securities - commercial 109,826 0 (4,414 ) 105,412 464,611 1,821 (2,988 ) 463,444 Collateralized mortgage obligations 11,936 0 (429 ) 11,507 919,486 9,214 (3,067 ) 925,633 Obligations of state and other political subdivisions 11,606 440 (228 ) 11,818 542,265 12,496 (504 ) 554,257 Asset-backed securities 0 0 0 0 502,018 1,180 (1,790 ) 501,408 Other securities 0 0 0 0 78,996 853 (324 ) 79,525 Total $ 158,305 $ 512 $ (5,742 ) $ 153,075 $ 3,096,085 $ 30,204 $ (12,478 ) $ 3,113,811 The following is a summary of HTM and AFS investment securities as of December 31, 2018 : Held-to-maturity Available-for-sale (Dollars in thousands) Amortized Unrecognized gain Unrecognized Fair Amortized Unrealized Unrealized Fair U.S. Treasuries $ 0 $ 0 $ 0 $ 0 $ 99 $ 0 $ (2 ) $ 97 Securities of U.S. government agencies and corporations 0 0 0 0 32,095 57 (233 ) 31,919 Mortgage-backed securities - residential 25,565 0 (1,045 ) 24,520 565,071 691 (7,163 ) 558,599 Mortgage-backed securities - commercial 147,780 258 (4,385 ) 143,653 423,797 819 (3,581 ) 421,035 Collateralized mortgage obligations 12,540 0 (633 ) 11,907 928,586 4,319 (6,158 ) 926,747 Obligations of state and other political subdivisions 243,443 1,954 (1,359 ) 244,038 257,300 2,554 (1,429 ) 258,425 Asset-backed securities 0 0 0 0 511,430 611 (2,810 ) 509,231 Other securities 0 0 0 0 73,948 358 (1,104 ) 73,202 Total $ 429,328 $ 2,212 $ (7,422 ) $ 424,118 $ 2,792,326 $ 9,409 $ (22,480 ) $ 2,779,255
Summary of Investment Securities by Estimated Maturity	The following table provides a summary of investment securities by contractual maturity as of March 31, 2019 , except for residential and commercial mortgage-backed securities, collateralized mortgage obligations and asset-backed securities, which are shown as single totals due to the unpredictability of the timing in principal repayments. Held-to-maturity Available-for-sale (Dollars in thousands) Amortized cost Fair value Amortized cost Fair value By Contractual Maturity: Due in one year or less $ 0 $ 0 $ 18,503 $ 18,522 Due after one year through five years 0 0 52,079 52,547 Due after five years through ten years 4,247 4,579 162,531 165,532 Due after ten years 7,359 7,239 419,127 427,878 Mortgage-backed securities - residential 24,937 24,338 557,730 558,847 Mortgage-backed securities - commercial 109,826 105,412 464,611 463,444 Collateralized mortgage obligations 11,936 11,507 919,486 925,633 Asset-backed securities 0 0 502,018 501,408 Total $ 158,305 $ 153,075 $ 3,096,085 $ 3,113,811
Age of Gross Unrealized Losses and Associated Fair Value by Investment Category	The following tables provide the fair value and gross unrealized losses on investment securities in an unrealized loss position, aggregated by investment category and the length of time the individual securities have been in a continuous loss position: March 31, 2019 Less than 12 months 12 months or more Total (Dollars in thousands) Fair value Unrealized loss Fair Unrealized Fair Unrealized U.S. Treasuries $ 0 $ 0 $ 98 $ (1 ) $ 98 $ (1 ) Securities of U.S. Government agencies and corporations 6,046 (77 ) 13,946 (278 ) 19,992 (355 ) Mortgage-backed securities - residential 12,585 (322 ) 239,305 (3,798 ) 251,890 (4,120 ) Mortgage-backed securities - commercial 140,670 (264 ) 195,282 (7,138 ) 335,952 (7,402 ) Collateralized mortgage obligations 90,610 (431 ) 212,286 (3,065 ) 302,896 (3,496 ) Obligations of state and other political subdivisions 12,080 (30 ) 42,954 (702 ) 55,034 (732 ) Asset-backed securities 224,565 (1,325 ) 48,376 (465 ) 272,941 (1,790 ) Other securities 8,636 (78 ) 7,545 (246 ) 16,181 (324 ) Total $ 495,192 $ (2,527 ) $ 759,792 $ (15,693 ) $ 1,254,984 $ (18,220 ) December 31, 2018 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized (Dollars in thousands) value loss value loss value loss U.S. Treasuries $ 0 $ 0 $ 97 $ (2 ) $ 97 $ (2 ) Securities of U.S. Government agencies and corporations 0 0 16,777 (233 ) 16,777 (233 ) Mortgage-backed securities - residential 186,029 (935 ) 264,795 (7,273 ) 450,824 (8,208 ) Mortgage-backed securities - commercial 147,754 (369 ) 232,363 (7,597 ) 380,117 (7,966 ) Collateralized mortgage obligations 194,795 (1,546 ) 240,514 (5,245 ) 435,309 (6,791 ) Obligations of state and other political subdivisions 62,805 (299 ) 86,644 (2,489 ) 149,449 (2,788 ) Asset-backed securities 336,437 (2,312 ) 37,105 (498 ) 373,542 (2,810 ) Other securities 33,752 (884 ) 4,570 (220 ) 38,322 (1,104 ) Total $ 961,572 $ (6,345 ) $ 882,865 $ (23,557 ) $ 1,844,437 $ (29,902 )

LOANS AND LEASES (Tables)

LOANS AND LEASES (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Commercial and Consumer Credit Exposure by Risk Attribute	Commercial and consumer credit exposure by risk attribute was as follows: As of March 31, 2019 Commercial Real Estate Lease (Dollars in thousands) & industrial Construction Commercial financing Total Pass $ 2,443,488 $ 457,508 $ 3,720,197 $ 92,527 $ 6,713,720 Special Mention 36,936 0 25,935 365 63,236 Substandard 63,003 605 56,047 2,681 122,336 Doubtful 0 0 0 0 0 Total $ 2,543,427 $ 458,113 $ 3,802,179 $ 95,573 $ 6,899,292 (Dollars in thousands) Residential real estate Home equity Installment Credit card Total Performing $ 958,185 $ 790,893 $ 90,515 $ 46,827 $ 1,886,420 Nonperforming 16,935 6,225 174 155 23,489 Total $ 975,120 $ 797,118 $ 90,689 $ 46,982 $ 1,909,909 As of December 31, 2018 Commercial Real Estate Lease (Dollars in thousands) & industrial Construction Commercial financing Total Pass $ 2,432,834 $ 548,323 $ 3,664,434 $ 90,902 $ 6,736,493 Special Mention 24,594 603 38,653 0 63,850 Substandard 57,233 9 51,594 2,513 111,349 Doubtful 0 0 0 0 0 Total $ 2,514,661 $ 548,935 $ 3,754,681 $ 93,415 $ 6,911,692 (Dollars in thousands) Residential real estate Home equity Installment Credit card Total Performing $ 939,936 $ 811,108 $ 93,038 $ 46,382 $ 1,890,464 Nonperforming 15,710 6,174 174 0 22,058 Total $ 955,646 $ 817,282 $ 93,212 $ 46,382 $ 1,912,522
Loan Delinquency, including Nonaccrual Loans	Loan delinquency, including loans classified as nonaccrual, was as follows: As of March 31, 2019 (Dollars in thousands) 30 – 59 60 – 89 > 90 days Total Current Subtotal Purchased impaired Total > 90 days Loans Commercial & industrial $ 917 $ 7,797 $ 8,255 $ 16,969 $ 2,521,040 $ 2,538,009 $ 5,418 $ 2,543,427 $ 23 Lease financing 0 0 0 0 95,573 95,573 0 95,573 0 Construction real estate 0 598 0 598 457,323 457,921 192 458,113 0 Commercial real estate 1,695 1,103 13,462 16,260 3,738,962 3,755,222 46,957 3,802,179 0 Residential real estate 3,329 1,495 4,326 9,150 933,896 943,046 32,074 975,120 0 Home equity 2,960 1,046 2,702 6,708 787,129 793,837 3,281 797,118 0 Installment 317 30 84 431 89,837 90,268 421 90,689 0 Credit card 193 206 155 554 46,428 46,982 0 46,982 155 Total $ 9,411 $ 12,275 $ 28,984 $ 50,670 $ 8,670,188 $ 8,720,858 $ 88,343 $ 8,809,201 $ 178 As of December 31, 2018 (Dollars in thousands) 30 – 59 60 – 89 > 90 days Total Current Subtotal Purchased impaired Total > 90 days Loans Commercial & industrial $ 13,369 $ 41 $ 7,423 $ 20,833 $ 2,488,450 $ 2,509,283 $ 5,378 $ 2,514,661 $ 0 Lease financing 352 0 0 352 93,063 93,415 0 93,415 0 Construction real estate 0 0 0 0 548,687 548,687 248 548,935 0 Commercial real estate 6,279 1,158 12,644 20,081 3,682,455 3,702,536 52,145 3,754,681 0 Residential real estate 11,060 2,976 4,535 18,571 902,404 920,975 34,671 955,646 0 Home equity 5,245 1,228 2,578 9,051 804,835 813,886 3,396 817,282 0 Installment 420 37 145 602 92,128 92,730 482 93,212 0 Credit card 541 96 63 700 45,682 46,382 0 46,382 63 Total $ 37,266 $ 5,536 $ 27,388 $ 70,190 $ 8,657,704 $ 8,727,894 $ 96,320 $ 8,824,214 $ 63
Loans Restructured During Period	The following tables provide information on loan modifications classified as TDRs during the three months ended March 31, 2019 and 2018 : Three months ended March 31, 2019 March 31, 2018 (Dollars in thousands) Number of loans Pre-modification loan balance Period end balance Number of loans Pre-modification loan balance Period end balance Commercial & industrial 5 $ 7,637 $ 7,661 4 $ 928 $ 913 Construction real estate 0 0 0 0 0 0 Commercial real estate 6 1,323 1,232 2 72 72 Residential real estate 5 458 458 2 93 93 Home equity 1 17 17 0 0 0 Installment 0 0 0 0 0 0 Total 17 $ 9,435 $ 9,368 8 $ 1,093 $ 1,078 For TDRs identified during the three months ended March 31, 2019 and 2018, there were no chargeoffs for the portion of TDRs determined to be uncollectible.
Loans Restructured, Modifications	The following table provides information on how TDRs were modified during the three months ended March 31, 2019 and 2018 : Three months ended March 31, (Dollars in thousands) 2019 2018 Extended maturities $ 2,877 $ 888 Adjusted interest rates 5,284 52 Combination of rate and maturity changes 508 0 Forbearance 557 0 Other (1) 142 138 Total $ 9,368 $ 1,078 (1) Includes covenant modifications and other concessions, or combination of concessions, that do not consist of interest rate adjustments, forbearance and maturity extensions
Nonaccrual, Restructured and Impaired Loans	The following table provides information on impaired loans, excluding purchased impaired loans: (Dollars in thousands) March 31, 2019 December 31, 2018 Impaired loans Nonaccrual loans (1) Commercial & industrial $ 19,263 $ 30,925 Lease financing 301 22 Construction real estate 7 9 Commercial real estate 21,082 20,500 Residential real estate 13,052 13,495 Home equity 5,581 5,580 Installment 170 169 Nonaccrual loans 59,456 70,700 Accruing troubled debt restructurings 22,817 16,109 Total impaired loans $ 82,273 $ 86,809 (1) Nonaccrual loans include nonaccrual TDRs of $13.1 million and $22.4 million as of March 31, 2019 and December 31, 2018 , respectively. Three months ended March 31, (Dollars in thousands) 2019 2018 Interest income effect on impaired loans Gross amount of interest that would have been recorded under original terms $ 1,613 $ 802 Interest included in income Nonaccrual loans 335 80 Troubled debt restructurings 236 124 Total interest included in income 571 204 Net impact on interest income $ 1,042 $ 598
Investment in Impaired Loans	First Financial's investment in impaired loans was as follows: As of March 31, 2019 As of December 31, 2018 (Dollars in thousands) Current balance Contractual principal balance Related allowance Current balance Contractual Related Loans with no related allowance recorded Commercial & industrial $ 30,142 $ 46,215 $ 0 $ 36,694 $ 42,561 $ 0 Lease financing 301 301 0 22 22 0 Construction real estate 8 25 0 9 26 0 Commercial real estate 22,708 29,530 0 23,513 31,375 0 Residential real estate 16,637 19,237 0 17,297 19,975 0 Home equity 6,225 7,232 0 6,351 7,461 0 Installment 174 310 0 174 563 0 Total 76,195 102,850 0 84,060 101,983 0 Loans with an allowance recorded Commercial & industrial 3,282 3,282 738 939 939 667 Lease financing 0 0 0 0 0 0 Construction real estate 0 0 0 0 0 0 Commercial real estate 2,498 3,579 651 1,509 1,509 461 Residential real estate 298 298 31 301 301 32 Home equity 0 0 0 0 0 0 Installment 0 0 0 0 0 0 Total 6,078 7,159 1,420 2,749 2,749 1,160 Total Commercial & industrial 33,424 49,497 738 37,633 43,500 667 Lease financing 301 301 0 22 22 0 Construction real estate 8 25 0 9 26 0 Commercial real estate 25,206 33,109 651 25,022 32,884 461 Residential real estate 16,935 19,535 31 17,598 20,276 32 Home equity 6,225 7,232 0 6,351 7,461 0 Installment 174 310 0 174 563 0 Total $ 82,273 $ 110,009 $ 1,420 $ 86,809 $ 104,732 $ 1,160 First Financial's average impaired loans by class and interest income recognized by class was as follows: Three months ended March 31, 2019 March 31, 2018 (Dollars in thousands) Average Interest Average Interest Loans with no related allowance recorded Commercial & industrial $ 33,418 $ 279 $ 7,867 $ 26 Lease financing 162 0 41 0 Construction real estate 9 0 28 1 Commercial real estate 23,111 103 21,400 99 Residential real estate 16,967 86 6,503 47 Home equity 6,288 38 4,214 20 Installment 174 1 281 0 Total 80,129 507 40,334 193 Loans with an allowance recorded Commercial & industrial 2,111 43 204 0 Lease financing 0 0 0 0 Construction real estate 0 0 0 0 Commercial real estate 2,004 19 1,739 3 Residential real estate 300 2 1,051 7 Home equity 0 0 101 1 Installment 0 0 0 0 Total 4,415 64 3,095 11 Total Commercial & industrial 35,529 322 8,071 26 Lease financing 162 0 41 0 Construction real estate 9 0 28 1 Commercial real estate 25,115 122 23,139 102 Residential real estate 17,267 88 7,554 54 Home equity 6,288 38 4,315 21 Installment 174 1 281 0 Total $ 84,544 $ 571 $ 43,429 $ 204
Changes in Other Real Estate Owned	Changes in OREO were as follows: Three months ended March 31, (Dollars in thousands) 2019 2018 Balance at beginning of period $ 1,401 $ 2,781 Additions Commercial & industrial 0 170 Residential real estate 504 459 Total additions 504 629 Disposals Commercial & industrial (22 ) (2,104 ) Residential real estate (161 ) (118 ) Total disposals (183 ) (2,222 ) Valuation adjustment Commercial & industrial 0 (97 ) Residential real estate (57 ) (26 ) Total valuation adjustment (57 ) (123 ) Balance at end of period $ 1,665 $ 1,065

ALLOWANCE FOR LOAN AND LEASE _2

ALLOWANCE FOR LOAN AND LEASE LOSSES (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Allowance for Loan and Lease Losses by Classification	Changes in the ALLL by loan category were as follows: Three months ended March 31, 2019 Real Estate (Dollars in thousands) Commercial and industrial Lease financing Construction Commercial Residential Home Equity Installment Credit card Total Allowance for loan and lease losses: Balance at beginning of period $ 18,746 $ 1,130 $ 3,413 $ 21,048 $ 4,964 $ 5,348 $ 362 $ 1,531 $ 56,542 Provision for loan and lease losses 13,268 343 (683 ) 493 125 185 19 333 14,083 Gross charge-offs (12,328 ) (100 ) 0 (1,214 ) (82 ) (468 ) (49 ) (341 ) (14,582 ) Recoveries 240 0 63 73 36 185 48 34 679 Total net charge-offs (12,088 ) (100 ) 63 (1,141 ) (46 ) (283 ) (1 ) (307 ) (13,903 ) Ending allowance for loan and lease losses $ 19,926 $ 1,373 $ 2,793 $ 20,400 $ 5,043 $ 5,250 $ 380 $ 1,557 $ 56,722 Three months ended March 31, 2018 Real Estate (Dollars in thousands) Commercial & industrial Lease financing Construction Commercial Residential Home equity Installment Credit card Total Allowance for loan and lease losses: Balance at beginning of period $ 17,598 $ 675 $ 3,577 $ 20,930 $ 4,683 $ 4,935 $ 307 $ 1,316 $ 54,021 Provision for loan and lease losses 889 (49 ) 690 815 114 (294 ) (49 ) 187 2,303 Loans charged off (885 ) 0 0 (2,176 ) (96 ) (242 ) (16 ) (254 ) (3,669 ) Recoveries 436 0 0 752 26 429 48 34 1,725 Total net charge-offs (449 ) 0 0 (1,424 ) (70 ) 187 32 (220 ) (1,944 ) Ending allowance for loan and lease losses $ 18,038 $ 626 $ 4,267 $ 20,321 $ 4,727 $ 4,828 $ 290 $ 1,283 $ 54,380 As of March 31, 2019 Real Estate (Dollars in thousands) Commercial & industrial Lease financing Construction Commercial Residential Home equity Installment Credit card Total Ending allowance balance attributable to loans Individually evaluated for impairment $ 738 $ 0 $ 0 $ 651 $ 31 $ 0 $ 0 $ 0 $ 1,420 Collectively evaluated for impairment 19,188 1,373 2,793 19,749 5,012 5,250 380 1,557 55,302 Ending allowance for loan and lease losses $ 19,926 $ 1,373 $ 2,793 $ 20,400 $ 5,043 $ 5,250 $ 380 $ 1,557 $ 56,722 Loans Individually evaluated for impairment $ 33,424 $ 301 $ 8 $ 25,206 $ 16,935 $ 6,225 $ 174 $ 0 $ 82,273 Collectively evaluated for impairment 2,510,003 95,272 458,105 3,776,973 958,185 790,893 90,515 46,982 8,726,928 Total loans $ 2,543,427 $ 95,573 $ 458,113 $ 3,802,179 $ 975,120 $ 797,118 $ 90,689 $ 46,982 $ 8,809,201 As of December 31, 2018 Real Estate (Dollars in thousands) Commercial & industrial Lease financing Construction Commercial Residential Home equity Installment Credit card Total Ending allowance balance attributable to loans Individually evaluated for impairment $ 667 $ 0 $ 0 $ 461 $ 32 $ 0 $ 0 $ 0 $ 1,160 Collectively evaluated for impairment 18,079 1,130 3,413 20,587 4,932 5,348 362 1,531 55,382 Ending allowance for loan and lease losses $ 18,746 $ 1,130 $ 3,413 $ 21,048 $ 4,964 $ 5,348 $ 362 $ 1,531 $ 56,542 Loans Individually evaluated for impairment $ 37,633 $ 22 $ 9 $ 25,022 $ 17,598 $ 6,351 $ 174 $ 0 $ 86,809 Collectively evaluated for impairment 2,477,028 93,393 548,926 3,729,659 938,048 810,931 93,038 46,382 8,737,405 Total loans $ 2,514,661 $ 93,415 $ 548,935 $ 3,754,681 $ 955,646 $ 817,282 $ 93,212 $ 46,382 $ 8,824,214

GOODWILL (Tables)

GOODWILL (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Carrying Amount of Goodwill	(Dollars in thousands) March 31, December 31, Balance at beginning of year $ 880,251 $ 204,084 Goodwill resulting from business combinations (524 ) 676,167 Balance at end of period $ 879,727 $ 880,251

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Lease, Cost [Table Text Block]	The components of lease expense were as follows: Three months ended (dollars in thousands) March 31, 2019 Operating lease cost $ 1,826 Short-term lease cost 1 Variable lease cost 597 Total operating lease cost $ 2,424
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Future minimum commitments due under these lease agreements as of March 31, 2019 are as follows: (dollars in thousands) Operating leases 2019 (remaining nine months) $ 5,361 2020 7,070 2021 6,569 2022 6,238 2023 6,248 Thereafter 54,378 Total lease payments 85,864 Less imputed interest 21,255 Total $ 64,609
Schedule of supplemental balance sheet information related to leases. [Table Text Block]	The lease term and discount rate at March 31, 2019 were as follows: Operating leases Weighted-average remaining lease term (years) 15.9 Weighted-average discount rate 3.5 %
Schedule of supplemental cash flow information related to leases [Table Text Block]	Supplemental cash information at March 31, 2019 related to leases was as follows: Three months ended (dollars in thousands) March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,823 ROU assets obtained in exchange for lease obligations Operating leases 60,249

BORROWINGS (Tables)

BORROWINGS (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule Of Remaining Contractual Maturity Of Secured Borrowings And Class Of Collateral Pledged Under Repurchase Agreements Table [Table Text Block]	The following shows the remaining contractual maturity of repurchase agreements by collateral pledged: (Dollars in thousands) Overnight and continuous Repurchase agreements Mortgage-backed securities $ 15,243 Collateralized mortgage obligations 79,772 Total $ 95,015
Summary of Long-term Debt	The following is a summary of First Financial's long-term debt: March 31, 2019 December 31, 2018 (Dollars in thousands) Amount Average rate Amount Average rate Subordinated notes $ 170,654 5.21 % $ 170,550 5.28 % Unamortized debt issuance costs (1,140 ) N/A (1,185 ) N/A FHLB borrowings 376,134 2.14 % 400,599 2.08 % Capital loan with municipality 775 0.00 % 775 0.00 % Total long-term debt $ 546,423 3.10 % $ 570,739 3.04 %

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Related Tax Effects Allocated to Other Comprehensive Income and Accumulated Other Comprehensive Income (Loss)	The related tax effects allocated to other comprehensive income and reclassifications out of accumulated other comprehensive income (loss) are as follows: Three months ended March 31, 2019 Total other comprehensive income Total accumulated other comprehensive income (loss) (Dollars in thousands) Prior to Reclass Pre-tax Tax effect Net of tax Beginning balance Net activity Cumulative effect of new standard Ending balance Unrealized gain (loss) on debt securities $ 29,725 $ (178 ) $ 29,903 $ (6,398 ) $ 23,505 $ (11,601 ) $ 23,505 $ 906 $ 12,810 Unrealized gain (loss) on derivatives 93 0 93 (21 ) 72 (217 ) 72 0 (145 ) Retirement obligation 0 (375 ) 375 (85 ) 290 (32,590 ) 290 0 (32,300 ) Total $ 29,818 $ (553 ) $ 30,371 $ (6,504 ) $ 23,867 $ (44,408 ) $ 23,867 $ 906 $ (19,635 ) Three months ended March 31, 2018 Total other comprehensive income Total accumulated other comprehensive income (loss) (Dollars in thousands) Prior to Reclass Pre-tax Tax effect Net of tax Beginning balance Net activity Cumulative effect of new standard Ending balance Unrealized gain (loss) on debt securities $ (12,536 ) $ 0 $ (12,536 ) $ 2,706 $ (9,830 ) $ (182 ) $ (9,830 ) $ (190 ) $ (10,202 ) Unrealized gain (loss) on derivatives 202 0 202 (46 ) 156 (577 ) 156 (124 ) (545 ) Retirement obligation 0 (419 ) 419 (96 ) 323 (19,631 ) 323 (4,779 ) (24,087 ) Total $ (12,334 ) $ (419 ) $ (11,915 ) $ 2,564 $ (9,351 ) $ (20,390 ) $ (9,351 ) $ (5,093 ) $ (34,834 )
Other Accumulated Comprehensive income reclassified from AOCI	The following table presents the activity reclassified from accumulated other comprehensive income into income during the three month periods ended March 31, 2019 and 2018 , respectively: Amount reclassified from (1) Three months ended March 31, (Dollars in thousands) 2019 2018 Affected Line Item in the Consolidated Statements of Income Realized gain (loss) on securities available-for-sale $ (178 ) $ 0 Net gain (loss) on sales of investments securities Defined benefit pension plan Amortization of prior service cost (2) 100 103 Other noninterest expense Recognized net actuarial loss (2) (475 ) (522 ) Other noninterest expense Defined benefit pension plan total (375 ) (419 ) Total reclassifications for the period, before tax $ (553 ) $ (419 ) (1) Negative amounts are reductions to net income. (2)

DERIVATIVES (Tables)

DERIVATIVES (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Derivative Financial Instruments and Balances	The following table details the classification and amounts recognized in the Consolidated Balance Sheets for client derivatives: March 31, 2019 December 31, 2018 Estimated fair value Estimated fair value (Dollars in thousands) Balance sheet classification Notional amount Gain Loss Notional amount Gain Loss Client derivatives - instruments associated with loans Matched interest rate swaps with borrower Accrued interest and other assets $ 1,406,914 $ 33,221 $ (5,580 ) $ 1,359,990 $ 17,402 $ (11,787 ) Matched interest rate swaps with counterparty Accrued interest and other liabilities 1,406,914 5,580 (33,228 ) 1,359,990 11,787 (17,401 ) Total $ 2,813,828 $ 38,801 $ (38,808 ) $ 2,719,980 $ 29,189 $ (29,188 )
Disclosure by Type of Financial Instrument	The following table discloses the gross and net amounts of client derivative liabilities recognized in the Consolidated Balance Sheets: March 31, 2019 December 31, 2018 (Dollars in thousands) Gross amounts of recognized liabilities Gross amounts offset in the Consolidated Balance Sheets Net amounts of liabilities presented in the Consolidated Balance Sheets Gross amounts of recognized liabilities Gross amounts offset in the Consolidated Balance Sheets Net amounts of liabilities presented in the Consolidated Balance Sheets Client derivatives Matched interest rate swaps with counterparty $ 38,808 $ (36,980 ) $ 1,828 $ 29,189 $ (14,577 ) $ 14,612
Derivative Financial Instruments, Average Remaining Maturity and the Weighted-Average Interest Rates being Paid and Received	The following table details the derivative financial instruments, the average remaining maturities and the weighted-average interest rates being paid and received by First Financial at March 31, 2019 : Weighted-average rate (Dollars in thousands) Notional amount Average maturity (years) Fair value Receive Pay Client derivatives Receive fixed, matched interest rate swaps with borrower $ 1,406,914 6.1 $ 27,641 4.70 % 4.80 % Pay fixed, matched interest rate swaps with counterparty 1,406,914 6.1 (27,648 ) 4.80 % 4.70 % Total client derivatives $ 2,813,828 6.1 $ (7 ) 4.75 % 4.75 %

EMPLOYEE BENEFIT PLANS (Tables)

EMPLOYEE BENEFIT PLANS (Tables)	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [Abstract]
Employee Benefit Plan Amounts Recognized in the Consolidated Balance Sheets and Consolidated Statements of Income	The following table sets forth information concerning amounts recognized in First Financial’s Consolidated Statements of Income related to the Company's pension plan: Three months ended March 31, (Dollars in thousands) 2019 2018 Service cost $ 1,750 $ 1,295 Interest cost 700 590 Expected return on assets (2,450 ) (2,460 ) Amortization of prior service cost (100 ) (103 ) Net actuarial loss 475 522 Net periodic benefit cost (income) $ 375 $ (156 )

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share: Three months ended March 31, (Dollars in thousands, except per share data) 2019 2018 Numerator Net income available to common shareholders $ 45,839 $ 30,506 Denominator Basic earnings per common share - weighted average shares 97,926,088 61,654,686 Effect of dilutive securities Employee stock awards 510,223 464,254 Warrants 0 61,804 Diluted earnings per common share - adjusted weighted average shares 98,436,311 62,180,744 Earnings per share available to common shareholders Basic $ 0.47 $ 0.49 Diluted $ 0.47 $ 0.49

FAIR VALUE DISCLOSURES (Tables)

FAIR VALUE DISCLOSURES (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Estimated Fair Values of Financial Instruments	The estimated fair values of First Financial’s financial instruments not measured at fair value on a recurring or nonrecurring basis in the consolidated financial statements were as follows: Carrying Estimated fair value (Dollars in thousands) value Total Level 1 Level 2 Level 3 March 31, 2019 Financial assets Cash and short-term investments $ 219,228 $ 219,228 $ 219,228 $ 0 $ 0 Investment securities held-to-maturity 158,305 153,075 0 153,075 0 Other investments 115,731 N/A N/A N/A N/A Loans held for sale 8,217 8,217 0 8,217 0 Loans and leases 8,752,479 8,651,343 0 0 8,651,343 Accrued interest receivable 44,171 44,171 0 14,230 29,941 Financial liabilities Deposits 10,133,897 10,117,317 0 10,117,317 0 Short-term borrowings 1,047,415 1,047,415 1,047,415 0 0 Long-term debt 546,423 538,743 0 538,743 0 Accrued interest payable 12,449 12,449 2,907 9,542 0 Carrying Estimated fair value (Dollars in thousands) value Total Level 1 Level 2 Level 3 December 31, 2018 Financial assets Cash and short-term investments $ 273,959 $ 273,959 $ 273,959 $ 0 $ 0 Investment securities held-to-maturity 429,328 424,118 0 424,118 0 Other investments 115,660 N/A N/A N/A N/A Loans held for sale 4,372 4,372 0 4,372 0 Loans and leases 8,767,672 8,662,868 0 0 8,662,868 Accrued interest receivable 41,816 41,816 0 13,819 27,997 Financial liabilities Deposits 10,140,394 10,113,475 0 10,113,475 0 Short-term borrowings 1,040,691 1,040,691 1,040,691 0 0 Long-term debt 570,739 557,933 0 557,933 0 Accrued interest payable 12,126 12,126 2,035 10,091 0
Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	The financial assets and liabilities measured at fair value on a recurring basis in the consolidated financial statements were as follows: Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 Assets/liabilities at fair value March 31, 2019 Assets Derivatives $ 0 $ 39,062 $ 0 $ 39,062 Investment securities available-for-sale 98 3,100,358 13,355 3,113,811 Total $ 98 $ 3,139,420 $ 13,355 $ 3,152,873 Liabilities Derivatives $ 0 $ 38,985 $ 0 $ 38,985 Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 Assets/liabilities at fair value December 31, 2018 Assets Derivatives $ 0 $ 29,543 $ 0 $ 29,543 Investment securities available-for-sale 97 2,764,443 14,715 2,779,255 Total $ 97 $ 2,793,986 $ 14,715 $ 2,808,798 Liabilities Derivatives $ 0 $ 29,336 $ 0 $ 29,336
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table presents a reconciliation for certain AFS securities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the three months ended March 31, 2019 . No AFS securities were measured at fair value on a recurring basis for the three months ended March 31, 2018. Three months ended (dollars in thousands) March 31, 2019 Beginning balance $ 14,715 Accretion (amortization) 7 Increase (decrease) in fair value 21 Settlements (1,388 ) Ending balance $ 13,355
Summary of Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis	The following table summarizes financial assets and liabilities measured at fair value on a nonrecurring basis. Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 March 31, 2019 Assets Impaired loans $ 0 $ 0 $ 4,391 OREO 0 0 1,046 Fair value measurements using (Dollars in thousands) Level 1 Level 2 Level 3 December 31, 2018 Assets Impaired loans $ 0 $ 0 $ 1,320 OREO 0 0 1,089

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table provides the purchase price calculation as of the acquisition date, identifiable assets purchased and liabilities assumed at their estimated fair value. As a condition of the merger, certain acquired assets and liabilities held for sale were divested subsequent to the closing of the merger. There was no gain or loss recorded in the Consolidated Statement of Income in conjunction with this divestiture. (Dollars in thousands) MainSource Purchase consideration Cash consideration $ 43 Stock consideration 1,043,424 Warrant consideration 14,460 Options consideration 1,577 Total purchase consideration 1,059,504 Assets acquired Cash 71,806 Investment securities available-for-sale 900,935 Investment securities held-to-maturity 171,423 Other investments 28,763 Loans 2,792,572 Premises and equipment 98,814 Intangible assets 42,887 Other assets 167,829 Assets held for sale 127,775 Total assets acquired 4,402,804 Liabilities assumed Deposits 3,263,920 Subordinated notes 49,027 FHLB advances 291,887 Other borrowings 205,620 Other liabilities 32,649 Liabilities held for sale 175,840 Total liabilities assumed 4,018,943 Net identifiable assets 383,861 Goodwill $ 675,643
Business Acquisition, Pro Forma Information, Nonrecurring Adjustments	Twelve months ended December 31, (Dollars in thousands, except per share data) 2018 2017 Pro Forma Condensed Combined Income Statement Information Net interest income $ 484,915 $ 454,579 Net income 221,122 130,402 Basic earnings per share 2.27 1.34 Diluted earnings per share 2.25 1.33

RECENTLY ADOPTED AND ISSUED A_2

RECENTLY ADOPTED AND ISSUED ACCOUNTING STANDARDS RECENTLY ADOPTED AND ISSUED ACCOUNTING STANDARDS - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019
OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForSaleOfSecuritiesDisproportionateTaxEffect		$ (190)
Operating Lease, Right-of-Use Asset	$ 59,000		$ 60,200
Operating Lease, Liability	64,609		$ 65,800
Debt Securities, Held-to-maturity, Transfer, Amount	268,700
Realized gain (loss) on debt securities transferred from HTM to AFS	$ 200

INVESTMENTS INVESTMENTS - Addit

INVESTMENTS INVESTMENTS - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018
Gain (Loss) on Securities [Line Items]
Realized gain (loss) on debt securities transferred from HTM to AFS	$ 200
NumberOfSecuritiesInSecurityPortfolio	1,395		1,417
NumberOfSecuritiesInUnrealizedLossPosition	303		504
Proceeds from Sale of Debt Securities, Available-for-sale	$ 0	$ 0
Available-for-sale Securities, Gross Realized Gains	0	0
Available-for-sale Securities, Gross Realized Losses	0	$ 0
Debt Securities, Held-to-maturity, Transfer, Amount	$ 268,700

INVESTMENTS - Summary of Held-T

INVESTMENTS - Summary of Held-To-Maturity and Available-For-Sale Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Investment Holdings [Line Items]
Total	$ 158,305	$ 429,328
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	512	2,212
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(5,742)	(7,422)
Held-to-Maturity Market Value	153,075	424,118
Total	3,096,085	2,792,326
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	30,204	9,409
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(12,478)	(22,480)
Investment securities available-for-sale	3,113,811	2,779,255
U.S. Treasuries
Investment Holdings [Line Items]
Total	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	0
Held-to-Maturity Market Value	0	0
Total	99	99
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	0	0
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(1)	(2)
Investment securities available-for-sale	98	97
Securities of U.S. government agencies and corporations
Investment Holdings [Line Items]
Total	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	0
Held-to-Maturity Market Value	0	0
Total	30,880	32,095
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	74	57
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(355)	(233)
Investment securities available-for-sale	30,599	31,919
Residential Mortgage Backed Securities [Member]
Investment Holdings [Line Items]
Total	24,937	25,565
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	72	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(671)	(1,045)
Held-to-Maturity Market Value	24,338	24,520
Total	557,730	565,071
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	4,566	691
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(3,449)	(7,163)
Investment securities available-for-sale	558,847	558,599
Commercial Mortgage Backed Securities [Member]
Investment Holdings [Line Items]
Total	109,826	147,780
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	258
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(4,414)	(4,385)
Held-to-Maturity Market Value	105,412	143,653
Total	464,611	423,797
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	1,821	819
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(2,988)	(3,581)
Investment securities available-for-sale	463,444	421,035
Collateralized Mortgage Backed Securities [Member]
Investment Holdings [Line Items]
Total	11,936	12,540
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(429)	(633)
Held-to-Maturity Market Value	11,507	11,907
Total	919,486	928,586
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	9,214	4,319
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(3,067)	(6,158)
Investment securities available-for-sale	925,633	926,747
Obligations of state and other political subdivisions
Investment Holdings [Line Items]
Total	11,606	243,443
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	440	1,954
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(228)	(1,359)
Held-to-Maturity Market Value	11,818	244,038
Total	542,265	257,300
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	12,496	2,554
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(504)	(1,429)
Investment securities available-for-sale	554,257	258,425
Asset-backed Securities [Member]
Investment Holdings [Line Items]
Total	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	0
Held-to-Maturity Market Value	0	0
Total	502,018	511,430
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	1,180	611
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(1,790)	(2,810)
Investment securities available-for-sale	501,408	509,231
Other securities
Investment Holdings [Line Items]
Total	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	0
Held-to-Maturity Market Value	0	0
Total	78,996	73,948
Available for Sale Securities Gross Unrealized Gain Accumulated In Investments	853	358
Available for Sale Securities Gross Unrealized Loss Accumulated In Investments	(324)	(1,104)
Investment securities available-for-sale	$ 79,525	$ 73,202

INVESTMENTS - Summary of Invest

INVESTMENTS - Summary of Investment Securities by Estimated Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Held-to-Maturity Amortized Cost
Amortized Cost	$ 158,305	$ 429,328
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	153,075	424,118
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	3,096,085	2,792,326
Available-for-Sale Market Value
Investment securities available-for-sale	3,113,811	2,779,255
One Year or Less [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	0
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	0
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	18,503
Available-for-Sale Market Value
Investment securities available-for-sale	18,522
After One Year Through Five Years [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	0
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	0
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	52,079
Available-for-Sale Market Value
Investment securities available-for-sale	52,547
After Five Years Through Ten Years [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	4,247
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	4,579
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	162,531
Available-for-Sale Market Value
Investment securities available-for-sale	165,532
After Ten Years [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	7,359
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	7,239
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	419,127
Available-for-Sale Market Value
Investment securities available-for-sale	427,878
Residential Mortgage Backed Securities [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	24,937	25,565
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	24,338	24,520
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	557,730	565,071
Available-for-Sale Market Value
Investment securities available-for-sale	558,847	558,599
Commercial Mortgage Backed Securities [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	109,826	147,780
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	105,412	143,653
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	464,611	423,797
Available-for-Sale Market Value
Investment securities available-for-sale	463,444	421,035
Collateralized Mortgage Backed Securities [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	11,936	12,540
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	11,507	11,907
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	919,486	928,586
Available-for-Sale Market Value
Investment securities available-for-sale	925,633	926,747
Asset-backed Securities [Member]
Held-to-Maturity Amortized Cost
Amortized Cost	0	0
Held-to-Maturity Market Value
Debt Securities, Held-to-maturity, Fair Value	0	0
Available-for-Sale Amortized Cost
Available-for-sale Securities, Amortized Cost Basis	502,018	511,430
Available-for-Sale Market Value
Investment securities available-for-sale	$ 501,408	$ 509,231

INVESTMENTS - Age of Gross Unre

INVESTMENTS - Age of Gross Unrealized Losses and Associated Fair Value by Investment Category (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	$ 495,192	$ 961,572
Less than 12 Months Unrealized Loss	(2,527)	(6,345)
12 Months or More Fair Value	759,792	882,865
12 Months or More Unrealized Loss	(15,693)	(23,557)
Total Fair Value	1,254,984	1,844,437
Total Unrealized Loss	(18,220)	(29,902)
U.S. Treasuries
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	0	0
Less than 12 Months Unrealized Loss	0	0
12 Months or More Fair Value	98	97
12 Months or More Unrealized Loss	(1)	(2)
Total Fair Value	98	97
Total Unrealized Loss	(1)	(2)
Securities of U.S. government agencies and corporations
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	6,046	0
Less than 12 Months Unrealized Loss	(77)	0
12 Months or More Fair Value	13,946	16,777
12 Months or More Unrealized Loss	(278)	(233)
Total Fair Value	19,992	16,777
Total Unrealized Loss	(355)	(233)
Residential Mortgage Backed Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	12,585	186,029
Less than 12 Months Unrealized Loss	(322)	(935)
12 Months or More Fair Value	239,305	264,795
12 Months or More Unrealized Loss	(3,798)	(7,273)
Total Fair Value	251,890	450,824
Total Unrealized Loss	(4,120)	(8,208)
Commercial Mortgage Backed Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	140,670	147,754
Less than 12 Months Unrealized Loss	(264)	(369)
12 Months or More Fair Value	195,282	232,363
12 Months or More Unrealized Loss	(7,138)	(7,597)
Total Fair Value	335,952	380,117
Total Unrealized Loss	(7,402)	(7,966)
Collateralized Mortgage Backed Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	90,610	194,795
Less than 12 Months Unrealized Loss	(431)	(1,546)
12 Months or More Fair Value	212,286	240,514
12 Months or More Unrealized Loss	(3,065)	(5,245)
Total Fair Value	302,896	435,309
Total Unrealized Loss	(3,496)	(6,791)
Obligations of state and other political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	12,080	62,805
Less than 12 Months Unrealized Loss	(30)	(299)
12 Months or More Fair Value	42,954	86,644
12 Months or More Unrealized Loss	(702)	(2,489)
Total Fair Value	55,034	149,449
Total Unrealized Loss	(732)	(2,788)
Asset-backed Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	224,565	336,437
Less than 12 Months Unrealized Loss	(1,325)	(2,312)
12 Months or More Fair Value	48,376	37,105
12 Months or More Unrealized Loss	(465)	(498)
Total Fair Value	272,941	373,542
Total Unrealized Loss	(1,790)	(2,810)
Other securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 Months Fair Value	8,636	33,752
Less than 12 Months Unrealized Loss	(78)	(884)
12 Months or More Fair Value	7,545	4,570
12 Months or More Unrealized Loss	(246)	(220)
Total Fair Value	16,181	38,322
Total Unrealized Loss	$ (324)	$ (1,104)

LOANS AND LEASES - Additional I

LOANS AND LEASES - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured Loans, Portion Determined to be Uncollectible	$ 0	$ 0
Purchased impaired loans	88,343,000		$ 96,320,000
Restructured Loans, Nonaccrual Status	13,100,000		22,400,000
Write-downs	57,000	123,000
Real Estate Acquired Through Foreclosure	1,665,000	1,065,000	$ 1,401,000	$ 2,781,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured Loans, Loan Relationships, Review Threshold Amount Minimum	250,000
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured Loans, Loan Relationships, Review Threshold Amount Minimum	250,000
Write-downs	$ 57,000	$ 26,000

LOANS AND LEASES - Commercial a

LOANS AND LEASES - Commercial and Consumer Credit Exposure by Risk Attribute (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Commercial	$ 2,543,427	$ 2,514,661
Real Estate - Construction	458,113	548,935
Real Estate - Commercial	3,802,179	3,754,681
Lease financing	95,573	93,415
Total Commercial	6,899,292	6,911,692
Pass
Financing Receivable, Recorded Investment [Line Items]
Commercial	2,443,488	2,432,834
Real Estate - Construction	457,508	548,323
Real Estate - Commercial	3,720,197	3,664,434
Lease financing	92,527	90,902
Total Commercial	6,713,720	6,736,493
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Commercial	36,936	24,594
Real Estate - Construction	0	603
Real Estate - Commercial	25,935	38,653
Lease financing	365	0
Total Commercial	63,236	63,850
Substandard
Financing Receivable, Recorded Investment [Line Items]
Commercial	63,003	57,233
Real Estate - Construction	605	9
Real Estate - Commercial	56,047	51,594
Lease financing	2,681	2,513
Total Commercial	122,336	111,349
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Commercial	0	0
Real Estate - Construction	0	0
Real Estate - Commercial	0	0
Lease financing	0	0
Total Commercial	0	0
Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	975,120	955,646
Residential real estate | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	958,185	939,936
Residential real estate | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	16,935	15,710
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	797,118	817,282
Home equity | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	790,893	811,108
Home equity | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	6,225	6,174
Installment
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	90,689	93,212
Installment | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	90,515	93,038
Installment | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	174	174
Credit card
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	46,982	46,382
Credit card | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	46,827	46,382
Credit card | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	155	0
Total consumer loans
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	1,909,909	1,912,522
Total consumer loans | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	1,886,420	1,890,464
Total consumer loans | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, before Fees, Gross	$ 23,489	$ 22,058

LOANS AND LEASES - Loan Delinqu

LOANS AND LEASES - Loan Delinquency, including Nonaccrual Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 50,670	$ 70,190
Current	8,670,188	8,657,704
Loans and Leases Receivable, Gross	8,720,858	8,727,894
Purchased impaired loans	88,343	96,320
Total loans and leases	8,809,201	8,824,214
> 90 days past due and still accruing	178	63
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	9,411	37,266
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	12,275	5,536
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	28,984	27,388
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	16,969	20,833
Current	2,521,040	2,488,450
Loans and Leases Receivable, Gross	2,538,009	2,509,283
Purchased impaired loans	5,418	5,378
Total loans and leases	2,543,427	2,514,661
> 90 days past due and still accruing	23	0
Commercial | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	917	13,369
Commercial | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	7,797	41
Commercial | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	8,255	7,423
Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	352
Current	95,573	93,063
Loans and Leases Receivable, Gross	95,573	93,415
Purchased impaired loans	0	0
Total loans and leases	95,573	93,415
> 90 days past due and still accruing	0	0
Lease financing | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	352
Lease financing | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Lease financing | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Construction real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	598	0
Current	457,323	548,687
Loans and Leases Receivable, Gross	457,921	548,687
Purchased impaired loans	192	248
Total loans and leases	458,113	548,935
> 90 days past due and still accruing	0	0
Construction real estate | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Construction real estate | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	598	0
Construction real estate | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	16,260	20,081
Current	3,738,962	3,682,455
Loans and Leases Receivable, Gross	3,755,222	3,702,536
Purchased impaired loans	46,957	52,145
Total loans and leases	3,802,179	3,754,681
> 90 days past due and still accruing	0	0
Commercial real estate | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,695	6,279
Commercial real estate | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,103	1,158
Commercial real estate | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	13,462	12,644
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	9,150	18,571
Current	933,896	902,404
Loans and Leases Receivable, Gross	943,046	920,975
Purchased impaired loans	32,074	34,671
Total loans and leases	975,120	955,646
> 90 days past due and still accruing	0	0
Residential real estate | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	3,329	11,060
Residential real estate | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,495	2,976
Residential real estate | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	4,326	4,535
Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	6,708	9,051
Current	787,129	804,835
Loans and Leases Receivable, Gross	793,837	813,886
Purchased impaired loans	3,281	3,396
Total loans and leases	797,118	817,282
> 90 days past due and still accruing	0	0
Home equity | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	2,960	5,245
Home equity | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,046	1,228
Home equity | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	2,702	2,578
Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	431	602
Current	89,837	92,128
Loans and Leases Receivable, Gross	90,268	92,730
Purchased impaired loans	421	482
Total loans and leases	90,689	93,212
> 90 days past due and still accruing	0	0
Installment | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	317	420
Installment | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	30	37
Installment | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	84	145
Credit card
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	554	700
Current	46,428	45,682
Loans and Leases Receivable, Gross	46,982	46,382
Purchased impaired loans	0	0
Total loans and leases	46,982	46,382
> 90 days past due and still accruing	155	63
Credit card | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	193	541
Credit card | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	206	96
Credit card | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 155	$ 63

LOANS AND LEASES - Restructured

LOANS AND LEASES - Restructured Loans (Details)	3 Months Ended
	Mar. 31, 2019USD ($)loansd	Mar. 31, 2018USD ($)loans	Dec. 31, 2018USD ($)loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Extended Maturities	$ 2,877,000	$ 888,000
Adjusted Interest Rates	5,284,000	52,000
Combined Rate And Maturity	508,000	0
Forebearance Agreements	557,000	0
Other	142,000	138,000
Total	$ 9,368,000	$ 1,078,000
Restructured loans, Number of Loans | loans	17	8
Restructured loans, Restructured loans, Pre-Modification Loan Balance	$ 9,435,000	$ 1,093,000
Restructured loans, Period End Balance	9,368,000	1,078,000
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 6,900,000	0
Number of Restructured Loans | loans	201		196
Total restructured loans	$ 35,900,000		$ 38,500,000
Restructured loans on accrual status	22,817,000		16,109,000
Restructured Loans, Nonaccrual Status	13,100,000		22,400,000
Loans and Leases Receivable, Impaired, Commitment to Lend	0		0
Allowance for loan and lease losses lncluded in reserves for restructured loans	1,400,000		1,500,000
Restructured Loans, Portion Determined to be Uncollectible	0	$ 0
Accruing TDRs performing in accordance with restructured terms for more than one year	$ 7,500,000		$ 7,900,000
Restructured loans performance threshold (days) | d	90
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	2	0
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured loans, Number of Loans | loans	5	4
Restructured loans, Restructured loans, Pre-Modification Loan Balance	$ 7,637,000	$ 928,000
Restructured loans, Period End Balance	$ 7,661,000	$ 913,000
Construction real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured loans, Number of Loans | loans	0	0
Restructured loans, Restructured loans, Pre-Modification Loan Balance	$ 0	$ 0
Restructured loans, Period End Balance	$ 0	$ 0
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured loans, Number of Loans | loans	6	2
Restructured loans, Restructured loans, Pre-Modification Loan Balance	$ 1,323,000	$ 72,000
Restructured loans, Period End Balance	$ 1,232,000	$ 72,000
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured loans, Number of Loans | loans	5	2
Restructured loans, Restructured loans, Pre-Modification Loan Balance	$ 458,000	$ 93,000
Restructured loans, Period End Balance	458,000	$ 93,000
Restructured Loans, Loan Relationships, Review Threshold Amount Minimum	$ 250,000
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured loans, Number of Loans | loans	1	0
Restructured loans, Restructured loans, Pre-Modification Loan Balance	$ 17,000	$ 0
Restructured loans, Period End Balance	$ 17,000	$ 0
Installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Restructured loans, Number of Loans | loans	0	0
Restructured loans, Restructured loans, Pre-Modification Loan Balance	$ 0	$ 0
Restructured loans, Period End Balance	$ 0	$ 0

LOANS AND LEASES - Nonaccrual,

LOANS AND LEASES - Nonaccrual, Restructured and Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Modifications [Line Items]
Average current balance	$ 84,544	$ 43,429
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	64	11
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	507	193
Nonaccrual loans	59,456		$ 70,700
Accruing trouble debt restructurings	22,817		16,109
Total impaired loans	82,273		86,809
Restructured loans - nonaccrual status	13,100		22,400
Interest income effect
Gross amount of interest that would have been recorded under original terms	1,613	802
Interest included in income
Nonaccrual loans	335	80
Troubled debt restructurings	236	124
Total interest included in income	571	204
Net impact on interest income	1,042	598
Commercial
Financing Receivable, Modifications [Line Items]
Average current balance	35,529	8,071
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	43	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	279	26
Nonaccrual loans	19,263		30,925
Total impaired loans	33,424		37,633
Interest included in income
Total interest included in income	322	26
Lease financing
Financing Receivable, Modifications [Line Items]
Average current balance	162	41
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0	0
Nonaccrual loans	301		22
Total impaired loans	301		22
Interest included in income
Total interest included in income	0	0
Construction real estate
Financing Receivable, Modifications [Line Items]
Average current balance	9	28
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0	1
Nonaccrual loans	7		9
Total impaired loans	8		9
Interest included in income
Total interest included in income	0	1
Commercial real estate
Financing Receivable, Modifications [Line Items]
Average current balance	25,115	23,139
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	19	3
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	103	99
Nonaccrual loans	21,082		20,500
Total impaired loans	25,206		25,022
Interest included in income
Total interest included in income	122	102
Residential real estate
Financing Receivable, Modifications [Line Items]
Average current balance	17,267	7,554
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	2	7
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	86	47
Nonaccrual loans	13,052		13,495
Total impaired loans	16,935		17,598
Interest included in income
Total interest included in income	88	54
Home equity
Financing Receivable, Modifications [Line Items]
Average current balance	6,288	4,315
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	1
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	38	20
Nonaccrual loans	5,581		5,580
Total impaired loans	6,225		6,351
Interest included in income
Total interest included in income	38	21
Installment
Financing Receivable, Modifications [Line Items]
Average current balance	174	281
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	1	0
Nonaccrual loans	170		169
Total impaired loans	174		174
Interest included in income
Total interest included in income	1	0
Loans with no related allowance recorded [member]
Financing Receivable, Modifications [Line Items]
Average current balance	80,129	40,334
Total impaired loans	76,195		84,060
Loans with no related allowance recorded [member] | Commercial
Financing Receivable, Modifications [Line Items]
Average current balance	33,418	7,867
Total impaired loans	30,142		36,694
Loans with no related allowance recorded [member] | Lease financing
Financing Receivable, Modifications [Line Items]
Average current balance	162	41
Total impaired loans	301		22
Loans with no related allowance recorded [member] | Construction real estate
Financing Receivable, Modifications [Line Items]
Average current balance	9	28
Total impaired loans	8		9
Loans with no related allowance recorded [member] | Commercial real estate
Financing Receivable, Modifications [Line Items]
Average current balance	23,111	21,400
Total impaired loans	22,708		23,513
Loans with no related allowance recorded [member] | Residential real estate
Financing Receivable, Modifications [Line Items]
Average current balance	16,967	6,503
Total impaired loans	16,637		17,297
Loans with no related allowance recorded [member] | Home equity
Financing Receivable, Modifications [Line Items]
Average current balance	6,288	4,214
Total impaired loans	6,225		6,351
Loans with no related allowance recorded [member] | Installment
Financing Receivable, Modifications [Line Items]
Average current balance	174	281
Total impaired loans	174		174
Impaired Financing Receivables With Related Allowance [Member]
Financing Receivable, Modifications [Line Items]
Total impaired loans	6,078
Impaired Financing Receivables With Related Allowance [Member] | Commercial
Financing Receivable, Modifications [Line Items]
Average current balance	2,111	204
Total impaired loans	3,282		939
Impaired Financing Receivables With Related Allowance [Member] | Lease financing
Financing Receivable, Modifications [Line Items]
Average current balance	0	0
Total impaired loans	0		0
Impaired Financing Receivables With Related Allowance [Member] | Construction real estate
Financing Receivable, Modifications [Line Items]
Average current balance	0	0
Total impaired loans	0		0
Impaired Financing Receivables With Related Allowance [Member] | Commercial real estate
Financing Receivable, Modifications [Line Items]
Average current balance	2,004	1,739
Total impaired loans	2,498		1,509
Impaired Financing Receivables With Related Allowance [Member] | Residential real estate
Financing Receivable, Modifications [Line Items]
Average current balance	300	1,051
Total impaired loans	298		301
Impaired Financing Receivables With Related Allowance [Member] | Home equity
Financing Receivable, Modifications [Line Items]
Average current balance	0	101
Total impaired loans	0		0
Impaired Financing Receivables With Related Allowance [Member] | Installment
Financing Receivable, Modifications [Line Items]
Average current balance	0	0
Total impaired loans	0		0
Impaired Financing Receivables With Related Allowance [Member]
Financing Receivable, Modifications [Line Items]
Average current balance	$ 4,415	$ 3,095
Total impaired loans			$ 2,749

LOANS AND LEASES - Investment i

LOANS AND LEASES - Investment in Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 59,456		$ 70,700
Current balance	82,273		86,809
Contractual Principal Balance	110,009		104,732
Related Allowance	1,420		1,160
Average current balance	84,544	$ 43,429
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	64	11
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	507	193
Interest income recognized	571	204
Commercial
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	19,263		30,925
Current balance	33,424		37,633
Contractual Principal Balance	49,497		43,500
Related Allowance	738		667
Average current balance	35,529	8,071
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	43	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	279	26
Interest income recognized	322	26
Lease financing
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	301		22
Current balance	301		22
Contractual Principal Balance	301		22
Related Allowance	0		0
Average current balance	162	41
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0	0
Interest income recognized	0	0
Construction real estate
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	7		9
Current balance	8		9
Contractual Principal Balance	25		26
Related Allowance	0		0
Average current balance	9	28
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0	1
Interest income recognized	0	1
Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	21,082		20,500
Current balance	25,206		25,022
Contractual Principal Balance	33,109		32,884
Related Allowance	651		461
Average current balance	25,115	23,139
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	19	3
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	103	99
Interest income recognized	122	102
Residential real estate
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	13,052		13,495
Current balance	16,935		17,598
Contractual Principal Balance	19,535		20,276
Related Allowance	31		32
Average current balance	17,267	7,554
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	2	7
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	86	47
Interest income recognized	88	54
Home equity
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	5,581		5,580
Current balance	6,225		6,351
Contractual Principal Balance	7,232		7,461
Related Allowance	0		0
Average current balance	6,288	4,315
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	1
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	38	20
Interest income recognized	38	21
Installment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	170		169
Current balance	174		174
Contractual Principal Balance	310		563
Related Allowance	0		0
Average current balance	174	281
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	1	0
Interest income recognized	1	0
Loans with no related allowance recorded [member]
Financing Receivable, Impaired [Line Items]
Current balance	76,195		84,060
Contractual Principal Balance	102,850		101,983
Related Allowance	0		0
Average current balance	80,129	40,334
Loans with no related allowance recorded [member] | Commercial
Financing Receivable, Impaired [Line Items]
Current balance	30,142		36,694
Contractual Principal Balance	46,215		42,561
Related Allowance	0		0
Average current balance	33,418	7,867
Loans with no related allowance recorded [member] | Lease financing
Financing Receivable, Impaired [Line Items]
Current balance	301		22
Contractual Principal Balance	301		22
Related Allowance	0		0
Average current balance	162	41
Loans with no related allowance recorded [member] | Construction real estate
Financing Receivable, Impaired [Line Items]
Current balance	8		9
Contractual Principal Balance	25		26
Related Allowance	0		0
Average current balance	9	28
Loans with no related allowance recorded [member] | Commercial real estate
Financing Receivable, Impaired [Line Items]
Current balance	22,708		23,513
Contractual Principal Balance	29,530		31,375
Related Allowance	0		0
Average current balance	23,111	21,400
Loans with no related allowance recorded [member] | Residential real estate
Financing Receivable, Impaired [Line Items]
Current balance	16,637		17,297
Contractual Principal Balance	19,237		19,975
Related Allowance	0		0
Average current balance	16,967	6,503
Loans with no related allowance recorded [member] | Home equity
Financing Receivable, Impaired [Line Items]
Current balance	6,225		6,351
Contractual Principal Balance	7,232		7,461
Related Allowance	0		0
Average current balance	6,288	4,214
Loans with no related allowance recorded [member] | Installment
Financing Receivable, Impaired [Line Items]
Current balance	174		174
Contractual Principal Balance	310		563
Related Allowance	0		0
Average current balance	174	281
Impaired Financing Receivables With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Current balance	6,078
Contractual Principal Balance	7,159
Related Allowance	1,420
Impaired Financing Receivables With Related Allowance [Member] | Commercial
Financing Receivable, Impaired [Line Items]
Current balance	3,282		939
Contractual Principal Balance	3,282		939
Related Allowance	738		667
Average current balance	2,111	204
Impaired Financing Receivables With Related Allowance [Member] | Lease financing
Financing Receivable, Impaired [Line Items]
Current balance	0		0
Contractual Principal Balance	0		0
Related Allowance	0		0
Average current balance	0	0
Impaired Financing Receivables With Related Allowance [Member] | Construction real estate
Financing Receivable, Impaired [Line Items]
Current balance	0		0
Contractual Principal Balance	0		0
Related Allowance	0		0
Average current balance	0	0
Impaired Financing Receivables With Related Allowance [Member] | Commercial real estate
Financing Receivable, Impaired [Line Items]
Current balance	2,498		1,509
Contractual Principal Balance	3,579		1,509
Related Allowance	651		461
Average current balance	2,004	1,739
Impaired Financing Receivables With Related Allowance [Member] | Residential real estate
Financing Receivable, Impaired [Line Items]
Current balance	298		301
Contractual Principal Balance	298		301
Related Allowance	31		32
Average current balance	300	1,051
Impaired Financing Receivables With Related Allowance [Member] | Home equity
Financing Receivable, Impaired [Line Items]
Current balance	0		0
Contractual Principal Balance	0		0
Related Allowance	0		0
Average current balance	0	101
Impaired Financing Receivables With Related Allowance [Member] | Installment
Financing Receivable, Impaired [Line Items]
Current balance	0		0
Contractual Principal Balance	0		0
Related Allowance	0		0
Average current balance	0	0
Impaired Financing Receivables With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Current balance			2,749
Contractual Principal Balance			2,749
Related Allowance			$ 1,160
Average current balance	$ 4,415	$ 3,095

LOANS AND LEASES - Changes in O

LOANS AND LEASES - Changes in Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 1,401	$ 2,781
Additions	504	629
Disposals	(183)	(2,222)
Write-downs	57	123
Balance at end of period	1,665	1,065
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additions	0	170
Disposals	(22)	(2,104)
Write-downs	0	97
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additions	504	459
Disposals	(161)	(118)
Write-downs	$ 57	$ 26

ALLOWANCE FOR LOAN AND LEASE _3

ALLOWANCE FOR LOAN AND LEASE LOSSES - Changes in the Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	$ 14,083	$ 2,303
Loans and Leases Receivable, Allowance	56,722	54,380	$ 56,542	$ 54,021
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	14,582	3,669
Allowance for Loan and Lease Loss, Recovery of Bad Debts	679	1,725
Total net charge-offs	13,903	1,944
Ending allowance on loans individually evaluated for impairment	1,420		1,160
Ending allowance on loans collectively evaluated for impairment	55,302		55,382
Loans and Leases:
Ending balance of loans individually evaluated for impairment	82,273		86,809
Ending balance of loans collectively evaluated for impairment	8,726,928		8,737,405
Loans and Leases Receivable, Net of Deferred Income	8,809,201		8,824,214
Impaired Financing Receivable, Related Allowance	56,722		56,542
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	13,268	889
Loans and Leases Receivable, Allowance	19,926	18,038	18,746	17,598
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	12,328	885
Allowance for Loan and Lease Loss, Recovery of Bad Debts	240	436
Total net charge-offs	12,088	449
Ending allowance on loans individually evaluated for impairment	738		667
Ending allowance on loans collectively evaluated for impairment	19,188		18,079
Loans and Leases:
Ending balance of loans individually evaluated for impairment	33,424		37,633
Ending balance of loans collectively evaluated for impairment	2,510,003		2,477,028
Loans and Leases Receivable, Net of Deferred Income	2,543,427		2,514,661
Impaired Financing Receivable, Related Allowance	19,926		18,746
Lease financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	343	(49)
Loans and Leases Receivable, Allowance	1,373	626	1,130	675
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	(100)	0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0	0
Total net charge-offs	100	0
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	1,373		1,130
Loans and Leases:
Ending balance of loans individually evaluated for impairment	301		22
Ending balance of loans collectively evaluated for impairment	95,272		93,393
Loans and Leases Receivable, Net of Deferred Income	95,573		93,415
Impaired Financing Receivable, Related Allowance	1,373		1,130
Construction real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	(683)	690
Loans and Leases Receivable, Allowance	2,793	4,267	3,413	3,577
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	0	0
Allowance for Loan and Lease Loss, Recovery of Bad Debts	63	0
Total net charge-offs	(63)	0
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	2,793		3,413
Loans and Leases:
Ending balance of loans individually evaluated for impairment	8		9
Ending balance of loans collectively evaluated for impairment	458,105		548,926
Loans and Leases Receivable, Net of Deferred Income	458,113		548,935
Impaired Financing Receivable, Related Allowance	2,793		3,413
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	493	815
Loans and Leases Receivable, Allowance	20,400	20,321	21,048	20,930
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	1,214	2,176
Allowance for Loan and Lease Loss, Recovery of Bad Debts	73	752
Total net charge-offs	1,141	1,424
Ending allowance on loans individually evaluated for impairment	651		461
Ending allowance on loans collectively evaluated for impairment	19,749		20,587
Loans and Leases:
Ending balance of loans individually evaluated for impairment	25,206		25,022
Ending balance of loans collectively evaluated for impairment	3,776,973		3,729,659
Loans and Leases Receivable, Net of Deferred Income	3,802,179		3,754,681
Impaired Financing Receivable, Related Allowance	20,400		21,048
Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	125	114
Loans and Leases Receivable, Allowance	5,043	4,727	4,964	4,683
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	82	96
Allowance for Loan and Lease Loss, Recovery of Bad Debts	36	26
Total net charge-offs	46	70
Ending allowance on loans individually evaluated for impairment	31		32
Ending allowance on loans collectively evaluated for impairment	5,012		4,932
Loans and Leases:
Ending balance of loans individually evaluated for impairment	16,935		17,598
Ending balance of loans collectively evaluated for impairment	958,185		938,048
Loans and Leases Receivable, Net of Deferred Income	975,120		955,646
Impaired Financing Receivable, Related Allowance	5,043		4,964
Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	185	(294)
Loans and Leases Receivable, Allowance	5,250	4,828	5,348	4,935
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	468	242
Allowance for Loan and Lease Loss, Recovery of Bad Debts	185	429
Total net charge-offs	283	(187)
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	5,250		5,348
Loans and Leases:
Ending balance of loans individually evaluated for impairment	6,225		6,351
Ending balance of loans collectively evaluated for impairment	790,893		810,931
Loans and Leases Receivable, Net of Deferred Income	797,118		817,282
Impaired Financing Receivable, Related Allowance	5,250		5,348
Installment
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	19	(49)
Loans and Leases Receivable, Allowance	380	290	362	307
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	49	16
Allowance for Loan and Lease Loss, Recovery of Bad Debts	48	48
Total net charge-offs	1	(32)
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	380		362
Loans and Leases:
Ending balance of loans individually evaluated for impairment	174		174
Ending balance of loans collectively evaluated for impairment	90,515		93,038
Loans and Leases Receivable, Net of Deferred Income	90,689		93,212
Impaired Financing Receivable, Related Allowance	380		362
Credit card
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for Loan and Lease Losses	333	187
Loans and Leases Receivable, Allowance	1,557	1,283	1,531	$ 1,316
Allowance for loan and lease losses:
Allowance for Loan and Lease Losses, Write-offs	341	254
Allowance for Loan and Lease Loss, Recovery of Bad Debts	34	34
Total net charge-offs	(307)	$ (220)
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	1,557		1,531
Loans and Leases:
Ending balance of loans individually evaluated for impairment	0		0
Ending balance of loans collectively evaluated for impairment	46,982		46,382
Loans and Leases Receivable, Net of Deferred Income	46,982		46,382
Impaired Financing Receivable, Related Allowance	$ 1,557		$ 1,531

GOODWILL AND OTHER INTANGIBLE_2

GOODWILL AND OTHER INTANGIBLE ASSETS--Schedule of Goodwill (Details) - USD ($) $ in Thousands	Apr. 01, 2018	Mar. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Balance at beginning of period		$ 880,251	$ 204,084
Goodwill resulting from business combinations	$ 675,643	(524)	676,167
Balance at end of period		$ 879,727	$ 880,251

GOODWILL AND OTHER INTANGIBLE_3

GOODWILL AND OTHER INTANGIBLE ASSETS--Additional Information (Details) - USD ($) $ in Thousands	Apr. 01, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill resulting from business combinations	$ 675,643	$ (524)		$ 676,167
Goodwill		879,727		880,251	$ 204,084
Intangible Assets, Net (Excluding Goodwill)		38,600		40,800
Finite-Lived Core Deposits, Gross		35,800		$ 37,900
Other Depreciation and Amortization		2,000
Amortization of Intangible Assets		$ 2,045	$ 280
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization method		accelerated basis
Estimated weighted average life (in years)		8 years 10 months 24 days

LEASES - Lease Cost (Details)

LEASES - Lease Cost (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Lease, Cost [Abstract]
Operating Lease, Cost	$ 1,826
Short-term Lease, Cost	1
Variable Lease, Cost	597
Lease, Cost	$ 2,424

LEASES - Lease Maturity (Detail

LEASES - Lease Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 5,361
Lessee, Operating Lease, Liability, Payments, Due Year Two	7,070
Lessee, Operating Lease, Liability, Payments, Due Year Three	6,569
Lessee, Operating Lease, Liability, Payments, Due Year Four	6,238
Lessee, Operating Lease, Liability, Payments, Due Year Five	6,248
Lessee, Operating Lease, Liability, Payments, Due after Year Five	54,378
Lessee, Operating Lease, Liability, Payments, Due	85,864
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	21,255
Operating Lease, Liability	$ 64,609	$ 65,800

LEASES - Schedule of supplement

LEASES - Schedule of supplemental balance sheet information related to assets (Details)	Mar. 31, 2019
Leases [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	15 years 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	3.50%

LEASES - Supplemental cash flow

LEASES - Supplemental cash flow information related to leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Leases [Abstract]
Operating cash flows from operating leases	$ 1,823	$ 0
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 60,249

LEASES LEASES - Additional Info

LEASES LEASES - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Leases [Abstract]
Operating Lease, Right-of-Use Asset	$ 59,000	$ 60,200
Operating Lease, Liability	$ 64,609	$ 65,800

BORROWINGS - Repurchase Agreeme

BORROWINGS - Repurchase Agreements (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Securities Sold under Agreements to Repurchase	$ 95,015
Carrying Value of Securities Sold under Repurchase Agreements and Deposits Received for Securities Loaned	95,500	$ 85,500
Residential Mortgage Backed Securities [Member]
Securities Sold under Agreements to Repurchase	15,243
Collateralized Mortgage Obligations [Member]
Securities Sold under Agreements to Repurchase	$ 79,772

BORROWINGS Borrowings - - Addit

BORROWINGS Borrowings - - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Carrying Value of Securities Sold under Repurchase Agreements and Deposits Received for Securities Loaned	$ 95,500	$ 85,500
FHLB short-term borrowings	952,400	857,100
Line of Credit Facility, Maximum Borrowing Capacity	30,000
Commitments outstanding to extend credit	0	0
Long-term Debt	546,423	570,739
Subordinated debt	$ 120,000
Subordinated Borrowing, Interest Rate	5.125%
Subordinated debt	$ 170,654	$ 170,550
Debt, Weighted Average Interest Rate	5.21%	5.28%
Advances from Federal Home Loan Banks	$ 376,134	$ 400,599
Federal Home Loan Bank	2.14%	2.08%
Private Placement [Member]
Subordinated debt	$ 8,400
Debt, Weighted Average Interest Rate	7.40%
Private Placement [Member]
DebtInstrumentMinimumCallablePeriod	5 years
Subordinated Debt [Member]
Subordinated debt	$ 49,500
Debt Instrument Maturity Period	30 years
DebtInstrumentMinimumCallablePeriod	5 years

BORROWINGS - Schedule of Long-t

BORROWINGS - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Amount
Subordinated debt	$ 170,654	$ 170,550
Unamortized debt issuance costs	(1,140)	(1,185)
FHLB long-term advances	376,134	400,599
Capital loan with municipality	775	775
Total long-term debt	$ 546,423	$ 570,739
Average Rate
Debt, Weighted Average Interest Rate	5.21%	5.28%
Federal Home Loan Bank	2.14%	2.08%
Weighted average rate on other long-term debt	0.00%	0.00%
Total long-term debt	3.10%	3.04%

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Other Comprehensive Income (Loss), before Reclassification Adjustments and Tax [Abstract]
Unrealized gain (loss) on investment securities	$ 29,725	$ (12,536)
Unrealized gain (loss) on derivatives	93	202
Retirement obligation	0	0
Total	29,818	(12,334)
Other Comprehensive Income (Loss) Reclassifications before Tax [Abstract]
Unrealized gain (loss) on investment securities	(178)	0
Unrealized gain (loss) on derivatives	0	0
Retirement obligation	(375)	(419)
Total	(553)	(419)
Transactions Pre-tax
Unrealized gain (loss) on investment securities	29,903	(12,536)
Unrealized gain (loss) on derivatives	93	202
Unfunded pension obligation	375	419
Total	30,371	(11,915)
Transactions Tax-effect
Unrealized gain (loss) on investment securities	(6,398)	2,706
Unrealized gain (loss) on derivatives	(21)	(46)
Retirement obligation	(85)	(96)
Total	(6,504)	2,564
Transactions Net of tax
Unrealized gain (loss) on investment securities	23,505	(9,830)
Unrealized gain (loss) on derivatives	72	156
Retirement obligation	290	323
Total	23,867	(9,351)
Stranded Tax Effects
Unrealized gain (loss) on investment securities	906
Unrealized gain (loss) on Derivatives	0	(124)
Retirement obligation	0	(4,779)
Total	906	(5,093)
Balances Net of tax
Unrealized gain (loss) on investment securities	12,810	(10,202)	$ (11,601)	$ (182)
Unrealized gain (loss) on cash flow hedges	(145)	(545)	(217)	(577)
Retirement obligation	(32,300)	(24,087)	(32,590)	(19,631)
Total	(19,635)	(34,834)	$ (44,408)	$ (20,390)
Accumulated other comprehensive income (loss)
Transactions Net of tax
Total	$ 23,867	$ (9,351)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE INCOME AMOUNT RECLASSIFIED FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Accumulated Comprehensive income reclassified from AOCI [Line Items]
Unrealized gain (loss) on investment securities	$ (178)	$ 0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	100	103
Defined Benefit Plan, Amortization of Gain (Loss)	(475)	(522)
Other Comprehensive Income, Reclassification, Amortization of Defined Benefit Plans items, Pre-tax	(375)	(419)
Total	$ (553)	$ (419)

DERIVATIVES - Additional Inform

DERIVATIVES - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)entity	Dec. 31, 2018USD ($)entity
Derivative [Line Items]
Maximum derivative notional position as a percentage of assets	35.00%
Maximum credit exposure as a percentage of capital	3.00%
Maximum single counterparty credit risk exposure	$ 20,000
Inerest-bearing deposit liability	$ 2,813,828	$ 2,719,980
Number of counterparties | entity	13	13
Derivative Asset	$ 38,801	$ 29,189
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	38,808	29,188
Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	32,800	20,800
Other Credit Derivatives [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	32,800	12,300
Credit Risk Derivative Liabilities, at Fair Value	100
Credit Risk Contract [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	119,800	138,400
Credit Risk Derivative Liabilities, at Fair Value	100	75
Accrued interest and other liabilities | Derivative [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	1,400,000	1,400,000
Derivative Asset	$ 27,100
Derivative Financial Instruments, Liabilities, Fair Value Disclosure		$ 4,900

DERIVATIVES - Summary of Deriva

DERIVATIVES - Summary of Derivative Financial Instruments and Balances (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	$ 2,813,828	$ 2,719,980
Derivative Asset	38,801	29,189
Estimate Fair Value Loss	(38,808)	(29,188)
Other Credit Derivatives [Member]
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	32,800	12,300
Credit Risk Derivative Liabilities, at Fair Value	100
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	1,406,914	1,359,990
Derivative Asset	5,580	11,787
Estimate Fair Value Loss	(33,228)	(17,401)
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	1,406,914	1,359,990
Derivative Asset	33,221	17,402
Estimate Fair Value Loss	$ (5,580)	$ (11,787)

DERIVATIVES DERIVATIVES - Discl

DERIVATIVES DERIVATIVES - Disclosure by Type of Financial Instrument (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Credit Risk Contract [Member]
Derivatives, Fair Value [Line Items]
Credit Risk Derivative Liabilities, at Fair Value	$ 100	$ 75
Fair Value Hedges | Matched interest rate swaps | Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of recognized liabilities	38,808	29,189
Derivative Liability, Fair Value, Gross Asset	(36,980)	(14,577)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	$ 1,828	$ 14,612

DERIVATIVES - Derivative Financ

DERIVATIVES - Derivative Financial Instruments, Average Remaining Maturity and the Weighted-Average Interest Rates being Paid and Received (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Value	$ 2,813,828	$ 2,719,980
Interest Rate Swap
Derivative [Line Items]
Notional Value	$ 2,813,828
Average Maturity (years)	6 years 1 month 6 days
Fair Value	$ (7)
Weighted-Average Rate Receive	4.75%
Weighted-Average Rate Pay	4.75%
Interest Rate Swap | Derivative Financial Instruments Receive Fixed Pay Variable
Derivative [Line Items]
Notional Value	$ 1,406,914
Average Maturity (years)	6 years 1 month 6 days
Fair Value	$ 27,641
Weighted-Average Rate Receive	4.70%
Weighted-Average Rate Pay	4.80%
Interest Rate Swap | Derivative Financial Instruments Receive Variable Pay Fixed
Derivative [Line Items]
Notional Value	$ 1,406,914
Average Maturity (years)	6 years 1 month 6 days
Fair Value	$ (27,648)
Weighted-Average Rate Receive	4.80%
Weighted-Average Rate Pay	4.70%

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Commitments and Contingencies Disclosure [Line Items]
Reserves for unfunded commitments	$ 800,000		$ 700,000
Commitments outstanding to extend credit	0		0
Loans and Leases Receivable, Commitments, Fixed Rates	182,500,000		174,000,000
Loans and Leases Receivable, Commitments, Variable Rates	$ 2,900,000,000		$ 2,900,000,000
Loan Commitments, Fixed Interest Rate Range, Minimum	0.00%
Loan Commitments, Fixed Interest Rate Range, Maximum	21.00%
Loan Commitments, Fixed Rate, Maturities, Minimum	1 year		1 year
Loan Commitments, Fixed Rate, Maturities, Maximum	30 years		30 years
Letters of credit issued to guarantee performance of a client to a third party	$ 33,400,000		$ 32,700,000
Affordable Housing Program Obligation	36,200,000		39,400,000
Amortization Method Qualified Affordable Housing Project Investments, Amortization	1,600,000	$ 1,300,000
Affordable housing contingent commitment	0		0
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	3,700,000		3,900,000
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	3,700,000		3,900,000
Estimated Litigation Liability	0		0
Commitments to Extend Credit
Commitments and Contingencies Disclosure [Line Items]
Commitments outstanding to extend credit	3,100,000,000		3,000,000,000
Affordable housing investment [Member]
Commitments and Contingencies Disclosure [Line Items]
Low-income housing tax credit	1,600,000	1,100,000
Historic tax credit [Member]
Commitments and Contingencies Disclosure [Line Items]
Low-income housing tax credit	$ 36,000	$ 100,000
Maximum [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Commitments, Variable Rates			0.210
Minimum [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Commitments, Variable Rates			$ 0

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense	$ 9,921	$ 7,653
Effective tax rate	17.80%	20.10%
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 2,400		$ 2,900
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0		$ 0

EMPLOYEE BENEFIT PLANS - Additi

EMPLOYEE BENEFIT PLANS - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Retirement Benefits [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	$ 0
Payment for Pension Benefits	0		$ 0
Pension Cost (Reversal of Cost)	$ 375,000	$ (156,000)

EMPLOYEE BENEFIT PLANS EMPLOYEE

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS - Employee benefit plan amounts recognized in the Consolidated Balance Sheets and Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ 1,750	$ 1,295
Interest cost	700	590
Expected return on plan assets	(2,450)	(2,460)
Amortization of prior service cost	(100)	(103)
Defined Benefit Plan, Amortization of Gain (Loss)	475	522
Net periodic benefit cost (income)	$ 375	$ (156)

REVENUE RECOGNITION REVENUE REC

REVENUE RECOGNITION REVENUE RECOGNITION (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue Recognition [Abstract]
Interchange income	$ 8.5	$ 5.4
Credit card expense	$ 2.9	$ 2

EARNINGS PER COMMON SHARE - Com

EARNINGS PER COMMON SHARE - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator for basic and diluted earnings per share -income available to common shareholders:
Net income	$ 45,839	$ 30,506
Denominator for basic earnings per share - weighted average shares	97,926,088	61,654,686
Effect of dilutive securities -
Employee stock awards	510,223	464,254
Warrants	0	61,804
Denominator for diluted earnings per share - adjusted weighted average shares	98,436,311	62,180,744
Basic	$ 0.47	$ 0.49
Diluted	$ 0.47	$ 0.49

EARNINGS PER COMMON SHARE - Add

EARNINGS PER COMMON SHARE - Additional Information (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share Disclosure [Line Items]
Investment Warrants, Exercise Price		$ 12.11
Antidilutive Warrants
Earnings Per Share Disclosure [Line Items]
Stock options and warrants with an exercise price greater than the average market price of the common shares not included in the computation of net income per diluted share	0	101,808
Antidilutive Stock Options
Earnings Per Share Disclosure [Line Items]
Stock options and warrants with an exercise price greater than the average market price of the common shares not included in the computation of net income per diluted share	0	0

FAIR VALUE DISCLOSURES - Estima

FAIR VALUE DISCLOSURES - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$ 38,808	$ 29,188
Financial assets
Investment securities held-to-maturity	158,305	429,328
Other investments	115,731	115,660
Deposits
Noninterest-bearing	2,488,157	2,492,434
Savings	3,100,894	3,167,325
Time	2,309,810	2,173,564
Carrying value
Financial assets
Cash and short-term investments	219,228	273,959
Investment securities held-to-maturity	158,305	429,328
Other investments	115,731	115,660
Loans held for sale	8,217	4,372
Loans and leases	8,752,479	8,767,672
Interest Receivable	44,171	41,816
Deposits
Deposits	10,133,897	10,140,394
Short-term borrowings	1,047,415	1,040,691
Long-term debt	546,423	570,739
Interest Payable	12,449	12,126
Fair value
Financial assets
Cash and short-term investments	219,228	273,959
Investment securities held-to-maturity	153,075	424,118
Loans held for sale	8,217	4,372
Loans and leases	8,651,343	8,662,868
Interest Receivable	44,171	41,816
Deposits
Deposits	10,117,317	10,113,475
Short-term borrowings	1,047,415	1,040,691
Long-term debt	538,743	557,933
Interest Payable	12,449	12,126
Fair Value, Inputs, Level 1 [Member] | Fair value
Financial assets
Cash and short-term investments	219,228	273,959
Investment securities held-to-maturity	0	0
Loans held for sale	0	0
Loans and leases	0	0
Interest Receivable	0	0
Deposits
Deposits	0	0
Short-term borrowings	1,047,415	1,040,691
Long-term debt	0	0
Interest Payable	2,907	2,035
Fair Value, Inputs, Level 2 [Member] | Fair value
Financial assets
Cash and short-term investments	0	0
Investment securities held-to-maturity	153,075	424,118
Loans held for sale	8,217	4,372
Loans and leases	0	0
Interest Receivable	14,230	13,819
Deposits
Deposits	10,117,317	10,113,475
Short-term borrowings	0	0
Long-term debt	538,743	557,933
Interest Payable	9,542	10,091
Fair Value, Inputs, Level 3 [Member] | Fair value
Financial assets
Cash and short-term investments	0	0
Investment securities held-to-maturity	0	0
Loans held for sale	0	0
Loans and leases	8,651,343	8,662,868
Interest Receivable	29,941	27,997
Deposits
Deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Interest Payable	$ 0	$ 0

FAIR VALUE DISCLOSURES - Summar

FAIR VALUE DISCLOSURES - Summary of Financial Assets and Liabilities Measure at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets
Derivatives	$ 38,801	$ 29,189
Investment securities available-for-sale	3,113,811	2,779,255
Liabilities
Derivatives	38,808	29,188
Fair Value, Measurements, Recurring
Assets
Derivatives	39,062	29,543
Investment securities available-for-sale	3,113,811	2,779,255
Total	3,152,873	2,808,798
Liabilities
Derivatives	38,985	29,336
Fair Value, Measurements, Recurring | Fair Value Measurements Using Level 1
Assets
Derivatives	0	0
Investment securities available-for-sale	98	97
Total	98	97
Liabilities
Derivatives	0	0
Fair Value, Measurements, Recurring | Fair Value Measurements Using Level 2
Assets
Derivatives	39,062	29,543
Investment securities available-for-sale	3,100,358	2,764,443
Total	3,139,420	2,793,986
Liabilities
Derivatives	38,985	29,336
Fair Value, Measurements, Recurring | Fair Value Measurements Using Level 3
Assets
Derivatives	0	0
Investment securities available-for-sale	13,355	14,715
Total	13,355	14,715
Liabilities
Derivatives	$ 0	$ 0

FAIR VALUE DISCLOSURES FAIR VAL

FAIR VALUE DISCLOSURES FAIR VALUE DISCLOSURES - Reconciliation of Gains and Losses on Level 3 Assets (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 14,715
Accretion (amortization)	7
Increase (decrease) in fair value	21
Settlements	(1,388)
Ending balance	$ 13,355

FAIR VALUE DISCLOSURES - Summ_2

FAIR VALUE DISCLOSURES - Summary of Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value Measurements Using Level 1
Assets
Impaired loans	$ 0	$ 0
Other Real Estate Owned, Fair Value Disclosure	0	0
Fair Value Measurements Using Level 2
Assets
Impaired loans	0	0
Other Real Estate Owned, Fair Value Disclosure	0	0
Fair Value Measurements Using Level 3
Assets
Impaired loans	4,391	1,320
Other Real Estate Owned, Fair Value Disclosure	$ 1,046	$ 1,089

BUSINESS COMBINATION - Addition

BUSINESS COMBINATION - Additional Information (Details) - USD ($) $ in Thousands	Apr. 01, 2018	Mar. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Business Acquisition, Number Of Shares Received by Acquiree	1.3875
Business Combination, Consideration Transferred	$ 1,059,504
Goodwill	675,643	$ (524)	$ 676,167
Payments for Merger Related Costs		$ 1,700	$ 37,800
Loans	2,792,572
Business Combination, Acquired Receivables, Gross Contractual Amount	$ 2,900,000

BUSINESS COMBINATIONS (Details)

BUSINESS COMBINATIONS (Details) - USD ($) $ in Thousands	Apr. 01, 2018	Mar. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Cash consideration	$ 43
Stock consideration	1,043,424
Warrant consideration	14,460
Options consideration	1,577
Total purchase consideration	1,059,504
Cash	71,806
Investment securities available-for-sale	900,935
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Held to Maturity Securities	171,423
Other investments	28,763
Loans	2,792,572
Premises and equipment	98,814
Intangible assets	42,887
Other assets	167,829
Assets held for sale	127,775
Total assets acquired	4,402,804
Deposits	3,263,920
Subordinated notes	49,027
FHLB advances	291,887
Other borrowings	205,620
Other liabilities	32,649
Liabilities held for sale	175,840
Total liabilities assumed	4,018,943
Net identifiable assets	383,861
Goodwill	$ 675,643	$ (524)	$ 676,167

BUSINESS COMBINATION Business A

BUSINESS COMBINATION Business Acquisition, Pro Forma Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Combinations [Abstract]
Business Acquisition, Pro Forma Revenue	$ 484,915	$ 454,579
Business Acquisition, Pro Forma Net Income (Loss)	$ 221,122	$ 130,402
Business Acquisition, Pro Forma Earnings Per Share, Basic	$ 2.27	$ 1.34
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 2.25	$ 1.33