NBT Bancorp (NBTB) 10-Q 9 May 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	Apr. 30, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Document Transition Report	false
Entity File Number	0-14703
Entity Registrant Name	NBT BANCORP INC
Entity Central Index Key	0000790359
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	16-1268674
Entity Address, Address Line One	52 South Broad Street
Entity Address, City or Town	Norwich
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	13815
City Area Code	607
Local Phone Number	337-2265
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	NBTB
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		47,149,315

Consolidated Balance Sheets (un

Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Cash and due from banks	$ 162,460	$ 173,811
Short-term interest-bearing accounts	156,632	31,378
Equity securities, at fair value	39,470	37,591
Securities available for sale, at fair value	1,418,471	1,430,858
Securities held to maturity (fair value $793,319 and $814,524, respectively)	890,863	905,267
Federal Reserve and Federal Home Loan Bank stock	37,336	45,861
Loans held for sale	3,263	3,371
Loans	9,688,077	9,650,713
Less allowance for loan losses	115,300	114,400
Net loans	9,572,777	9,536,313
Premises and equipment, net	80,239	80,675
Goodwill	361,851	361,851
Intangible assets, net	38,968	40,443
Bank owned life insurance	267,476	265,732
Other assets	409,393	395,889
Total assets	13,439,199	13,309,040
Liabilities
Demand (noninterest bearing)	3,359,789	3,413,829
Savings, NOW and money market	6,467,364	6,230,456
Time	1,368,136	1,324,709
Total deposits	11,195,289	10,968,994
Short-term borrowings	267,134	386,651
Long-term debt	29,759	29,796
Subordinated debt, net	120,101	119,744
Junior subordinated debt	101,196	101,196
Other liabilities	284,305	276,968
Total liabilities	11,997,784	11,883,349
Stockholders' equity
Preferred stock, $0.01 par value. 2,500,000 shares authorized	0	0
Common stock, $0.01 par value. 100,000,000 shares authorized; 53,974,492 shares issued	540	540
Additional paid-in-capital	740,792	740,943
Retained earnings	1,040,563	1,021,831
Accumulated other comprehensive loss	(164,492)	(160,934)
Common stock in treasury, at cost, 6,819,477 and 6,864,593 shares, respectively	(175,988)	(176,689)
Total stockholders' equity	1,441,415	1,425,691
Total liabilities and stockholders' equity	$ 13,439,199	$ 13,309,040

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Securities held to maturity fair value	$ 793,319	$ 814,524
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	2,500,000	2,500,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	53,974,492	53,974,492
Common stock in treasury, at cost (in shares)	6,819,477	6,864,593

Consolidated Statements of Inco

Consolidated Statements of Income (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Interest, fee and dividend income
Interest and fees on loans	$ 133,146	$ 100,899
Securities available for sale	7,124	7,616
Securities held to maturity	5,303	5,035
Other	1,364	642
Total interest, fee and dividend income	146,937	114,192
Interest expense
Deposits	44,339	11,144
Short-term borrowings	3,421	4,919
Long-term debt	290	47
Subordinated debt	1,800	1,334
Junior subordinated debt	1,913	1,682
Total interest expense	51,763	19,126
Net interest income	95,174	95,066
Provision for loan losses	5,579	3,909
Net interest income after provision for loan losses	89,595	91,157
Noninterest income
Service charges on deposit accounts	4,117	3,548
Card services income	5,195	4,845
Retirement plan administration fees	14,287	11,462
Wealth management	9,697	8,087
Insurance services	4,388	3,931
Bank owned life insurance income	2,352	1,878
Net securities gains (losses)	2,183	(4,998)
Other	3,173	2,656
Total noninterest income	45,392	31,409
Noninterest expense
Salaries and employee benefits	55,704	48,155
Technology and data services	9,750	9,007
Occupancy	8,098	7,220
Professional fees and outside services	4,853	4,178
Office supplies and postage	1,865	1,628
FDIC assessment	1,735	1,396
Advertising	812	649
Amortization of intangible assets	2,168	536
Loan collection and other real estate owned, net	553	855
Acquisition expenses	0	618
Other	6,235	5,080
Total noninterest expense	91,773	79,322
Income before income tax expense	43,214	43,244
Income tax expense	9,391	9,586
Net income	$ 33,823	$ 33,658
Earnings per share
Basic (in dollars per share)	$ 0.72	$ 0.78
Diluted (in dollars per share)	$ 0.71	$ 0.78

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Consolidated Statements of Comprehensive Income (Loss) (unaudited) [Abstract]
Net income	$ 33,823	$ 33,658
Securities available for sale:
Unrealized net holding (losses) gains arising during the period, gross	(5,292)	15,725
Tax effect	1,323	(3,931)
Unrealized net holding (losses) gains arising during the period, net	(3,969)	11,794
Reclassification adjustment for net losses in net income, gross	0	5,000
Tax effect	0	(1,250)
Reclassification adjustment for net losses in net income, net	0	3,750
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, gross	96	114
Tax effect	(24)	(28)
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, net	72	86
Total securities available for sale, net	(3,897)	15,630
Pension and other benefits:
Amortization of prior service cost and actuarial losses, gross	452	649
Tax effect	(113)	(163)
Amortization of prior service cost and actuarial losses, net	339	486
Total pension and other benefits, net	339	486
Total other comprehensive (loss) income	(3,558)	16,116
Comprehensive income	$ 30,265	$ 49,774

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in-Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Common Stock in Treasury [Member]	Total	Cumulative Effect Adjustment for ASU Implementation [Member] Common Stock [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Additional Paid-in-Capital [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Retained Earnings [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Accumulated Other Comprehensive (Loss) Income [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Common Stock in Treasury [Member]	Cumulative Effect Adjustment for ASU Implementation [Member]
Balance at Dec. 31, 2022	$ 497	$ 577,853	$ 958,433	$ (190,034)	$ (173,195)	$ 1,173,554
Balance (ASU 2022-02 [Member]) at Dec. 31, 2022							$ 0	$ 0	$ 502	$ 0	$ 0	$ 502
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	33,658	0	0	33,658
Cash dividends	0	0	(12,871)	0	0	(12,871)
Net issuance of shares to employee and other stock plans	0	(2,366)	0	0	601	(1,765)
Stock-based compensation	0	2,465	0	0	0	2,465
Other comprehensive (loss) income	0	0	0	16,116	0	16,116
Balance at Mar. 31, 2023	497	577,952	979,722	(173,918)	(172,594)	1,211,659
Balance at Dec. 31, 2023	540	740,943	1,021,831	(160,934)	(176,689)	1,425,691
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	33,823	0	0	33,823
Cash dividends	0	0	(15,091)	0	0	(15,091)
Purchase of treasury shares	0	0	0	0	(63)	(63)
Net issuance of shares to employee and other stock plans	0	(2,435)	0	0	764	(1,671)
Stock-based compensation	0	2,284	0	0	0	2,284
Other comprehensive (loss) income	0	0	0	(3,558)	0	(3,558)
Balance at Mar. 31, 2024	$ 540	$ 740,792	$ 1,040,563	$ (164,492)	$ (175,988)	$ 1,441,415

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Consolidated Statements of Changes in Stockholders' Equity (unaudited) [Abstract]
Cash dividends - per share (in dollars per share)	$ 0.32	$ 0.3
Purchase of treasury shares (in shares)	1,900
Net issuance of shares to employee benefit plans and other stock plans (in shares)	47,016	46,509

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities
Net income	$ 33,823	$ 33,658
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan losses	5,579	3,909
Depreciation and amortization of premises and equipment	2,855	2,579
Net amortization on securities	657	690
Amortization of intangible assets	2,168	536
Amortization of operating lease right-of-use assets	1,867	1,647
Excess tax benefit on stock-based compensation	(116)	(231)
Stock-based compensation expense	2,284	2,465
Bank owned life insurance income	(2,352)	(1,878)
Amortization of subordinated debt issuance costs	109	109
Proceeds from sale of loans held for sale	27,075	1,571
Originations of loans held for sale	(26,662)	(1,418)
Net gain on sale of loans held for sale	(40)	(16)
Net securities (gains) losses	(2,183)	4,998
Net change in other assets and other liabilities	(8,319)	(26,772)
Net cash provided by operating activities	36,745	21,847
Investing activities
Net cash used in acquisitions	(743)	(129)
Securities available for sale:
Proceeds from maturities, calls and principal paydowns	26,542	30,683
Proceeds from sales	2,284	0
Purchases	(19,676)	0
Securities held to maturity:
Proceeds from maturities, calls and principal paydowns	21,143	17,870
Purchases	(7,071)	(5,494)
Equity securities:
Purchases	(7)	0
Other:
Net increase in loans	(42,308)	(118,242)
Proceeds from Federal Home Loan Bank stock redemption	26,465	38,589
Purchases of Federal Home Loan Bank stock	(17,940)	(39,218)
Proceeds from settlement of bank owned life insurance	608	1,773
Purchases of premises and equipment, net	(2,425)	(1,392)
Net cash used in investing activities	(13,128)	(75,560)
Financing activities
Net increase in deposits	226,295	185,272
Net decrease in short-term borrowings	(119,517)	(109,786)
Proceeds from long-term debt	0	25,000
Repayments of long-term debt	(37)	(25)
Cash paid by employer for tax-withholding on stock issuance	(1,301)	(1,432)
Purchase of treasury stock	(63)	0
Cash dividends	(15,091)	(12,871)
Net cash provided by financing activities	90,286	86,158
Net increase in cash and cash equivalents	113,903	32,445
Cash and cash equivalents at beginning of period	205,189	197,350
Cash and cash equivalents at end of period	319,092	229,795
Cash paid during the period for:
Interest expense	55,313	17,066
Income taxes paid, net of refund	3,500	15,072
Acquisitions:
Fair value of assets acquired	$ 693	$ 150

Description of Business

Description of Business	3 Months Ended
	Mar. 31, 2024
Description of Business [Abstract]
Description of Business	1. Description of Business NBT Bancorp Inc. is a registered financial holding company incorporated in the state of Delaware in 1986, with its principal headquarters located in Norwich, New York. The principal assets of NBT Bancorp Inc. (collectively, the “Trusts”) NBT Bancorp Inc. The Company’s business, primarily conducted through the Bank, consists of providing commercial banking, retail banking and wealth management services primarily to customers in its market area, which includes upstate New York, northeastern Pennsylvania, southern New Hampshire, western Massachusetts, Vermont, southern Maine and central and northwestern

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited interim consolidated financial statements include the accounts of NBT Bancorp Inc. and its wholly-owned subsidiaries: the Bank, NBT Financial and NBT Holdings. In the opinion of management, the interim data includes all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the results for the interim periods in accordance with GAAP and in accordance with the instructions to Quarterly Report on Form 10-Q and Article 10 of Regulation S-X as promulgated by the SEC. Accordingly, the consolidated financial statements do not include all of the information and notes necessary for complete financial statements in conformity with GAAP. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s 2023 Annual Report on Form 10-K. 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. All material intercompany transactions have been eliminated in consolidation. Amounts previously reported in the consolidated financial statements are reclassified whenever necessary to conform to current period presentation. The Company has evaluated subsequent events for potential recognition and/or disclosure and there were none identified. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results may differ from those estimates and such differences could be material to the financial statements. Estimates associated with the allowance for credit losses, pension accounting, provision for income taxes, fair values of financial instruments and status of contingencies are particularly susceptible to material change in the near term.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2024
Recent Accounting Pronouncements [Abstract]
Recent Accounting Pronouncements	3. Recent Accounting Pronouncements Accounting Standards Issued Not Yet Adopted In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements , other than to meet the new disclosure requirements, In November 2023, the FASB issued ASU 2023-07, Improvements to Reportable Segment Disclosures In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures , that addresses requests for improved income tax disclosures from investors, lenders, creditors and other allocators of capital that use the financial statements to make capital allocation decisions. The ASU requires enhanced disclosures primarily related to existing rate reconciliation and income taxes paid information to help investors better assess how the Company’s operations and related tax risks and tax planning and operational opportunities affect the Company’s tax rate and prospects for future cash flows. The ASU 2023-09 improves the transparency of income tax disclosures. The amendments in this ASU are effective for the Company on January 1, 2025 and should be applied on a prospective basis. Retrospective application and early adoption are permitted. The adoption, other than to meet the new disclosure requirements, is not expected to have a material impact on the consolidated financial statements.

Securities

Securities	3 Months Ended
	Mar. 31, 2024
Securities [Abstract]
Securities	4. Securities The amortized cost, estimated fair value and unrealized gains (losses) of AFS securities are as follows: (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value As of March 31, 2024 U.S. treasury $ 133,442 $ - $ (8,759 ) $ 124,683 Federal agency 248,375 - (35,071 ) 213,304 State & municipal 96,054 1 (10,022 ) 86,033 Mortgage-backed: Government-sponsored enterprises 387,479 3 (45,461 ) 342,021 U.S. government agency securities 71,036 10 (7,520 ) 63,526 Collateralized mortgage obligations: Government-sponsored enterprises 452,853 49 (50,135 ) 402,767 U.S. government agency securities 170,293 - (26,034 ) 144,259 Corporate 48,451 - (6,573 ) 41,878 Total AFS securities $ 1,607,983 $ 63 $ (189,575 ) $ 1,418,471 As of December 31, 2023 U.S. treasury $ 133,302 $ - $ (8,278 ) $ 125,024 Federal agency 248,384 - (33,644 ) 214,740 State & municipal 96,251 11 (9,956 ) 86,306 Mortgage-backed: Government-sponsored enterprises 399,532 7 (44,264 ) 355,275 U.S. government agency securities 74,281 14 (7,302 ) 66,993 Collateralized mortgage obligations: Government-sponsored enterprises 452,715 15 (48,257 ) 404,473 U.S. government agency securities 162,171 - (25,100 ) 137,071 Corporate 48,442 - (7,466 ) 40,976 Total AFS securities $ 1,615,078 $ 47 $ (184,267 ) $ 1,430,858 There was no allowance for credit losses on AFS securities as of March 31, 2024 and December 31, 2023. During the three months ended March 31, 2023, the Company incurred a $5.0 million loss on the write-off of an AFS corporate debt security from a subordinated debt investment of a financial institution that failed. The $5.0 million loss was reclassified out of AOCI and into earnings in net securities gains (losses) in the unaudited interim consolidated statements of income. During the three months ended March 31, 2024 the Company sold the previously written-off security and recognized a gain of $2.3 million into earnings in net securities gains (losses) in the unaudited interim consolidated statements of income. The amortized cost, estimated fair value and unrealized gains (losses) of HTM securities are as follows: (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value As of March 31, 2024 Federal agency $ 100,000 $ - $ (18,440 ) $ 81,560 Mortgage-backed: Government-sponsored enterprises 224,344 - (34,187 ) 190,157 U.S. government agency securities 16,742 2 (736 ) 16,008 Collateralized mortgage obligations: Government-sponsored enterprises 182,813 - (13,466 ) 169,347 U.S. government agency securities 63,137 - (11,206 ) 51,931 State & municipal 303,827 99 (19,610 ) 284,316 Total HTM securities $ 890,863 $ 101 $ (97,645 ) $ 793,319 As of December 31, 2023 Federal agency $ 100,000 $ - $ (17,784 ) $ 82,216 Mortgage-backed: Government-sponsored enterprises 228,720 - (31,613 ) 197,107 U.S. government agency securities 17,086 3 (566 ) 16,523 Collateralized mortgage obligations: Government-sponsored enterprises 187,457 57 (12,021 ) 175,493 U.S. government agency securities 63,878 - (10,908 ) 52,970 State & municipal 308,126 211 (18,122 ) 290,215 Total HTM securities $ 905,267 $ 271 $ (91,014 ) $ 814,524 At March 31, 2024 and December 31, 2023, all of the mortgaged-backed HTM securities were comprised of U.S. government agency and government-sponsored enterprises securities. The Company recorded no gains from calls on HTM securities for the three months ended March 31, 2024 and 2023. AFS and HTM securities with amortized costs totaling $1.99 billion at March 31, 2024 and $2.03 billion at December 31, 2023 were pledged to secure public deposits and for other purposes required or permitted by law. Additionally, at March 31, 2024 and December 31, 2023, AFS and HTM securities with an amortized cost of $159.3 million and $177.2 million, respectively, were pledged as collateral for securities sold under repurchase agreements. The following table sets forth information with regard to gains and (losses) on equity securities: Three Months Ended March 31, (In thousands) 2024 2023 Net (losses) and gains recognized on equity securities $ (101 ) $ 2 Less: Net (losses) and gains recognized on equity securities sold during the period - - Unrealized (losses) and gains recognized on equity securities still held $ (101 ) $ 2 As of March 31, 2024 and December 31, 2023, the carrying value of equity securities without readily determinable fair values was $1.0 million. The Company performed a qualitative assessment to determine whether the investments were impaired and identified no areas of concern as of March 31, 2024 and 2023. There were no impairments, or downward or upward adjustments recognized for equity securities without readily determinable fair values during the three months ended March 31, 2024 and 2023. The following table sets forth information with regard to contractual maturities of debt securities at March 31, 2024: (In thousands) Amortized Cost Estimated Fair Value AFS debt securities: Within one year $ 50,294 $ 49,553 From one to five years 567,513 508,211 From five to ten years 314,839 277,648 After ten years 675,337 583,059 Total AFS debt securities $ 1,607,983 $ 1,418,471 HTM debt securities: Within one year $ 98,660 $ 98,460 From one to five years 125,141 119,411 From five to ten years 242,973 210,783 After ten years 424,089 364,665 Total HTM debt securities $ 890,863 $ 793,319 Maturities of mortgage-backed, collateralized mortgage obligations and asset-backed securities are stated based on their estimated average lives. Actual maturities may differ from estimated average lives or contractual maturities because, in certain cases, borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Except for U.S. government securities and government-sponsored enterprises securities, there were no holdings, when taken in the aggregate, of any single issuer that exceeded 10% of consolidated stockholders’ equity at March 31, 2024 and December 31, 2023. The following table sets forth information with regard to investment securities with unrealized losses, for which an allowance for credit losses has not been recorded, segregated according to the length of time the securities had been in a continuous unrealized loss position: Less Than 12 Months 12 Months or Longer Total (In thousands) Fair Value Unrealized Losses Number of Positions Fair Value Unrealized Losses Number of Positions Fair Value Unrealized Losses Number of Positions As of March 31, 2024 AFS securities: U.S. treasury $ - $ - - $ 124,683 $ (8,759 ) 8 $ 124,683 $ (8,759 ) 8 Federal agency - - - 213,304 (35,071 ) 16 213,304 (35,071 ) 16 State & municipal - - - 85,266 (10,022 ) 66 85,266 (10,022 ) 66 Mortgage-backed 136 (1 ) 9 404,618 (52,980 ) 158 404,754 (52,981 ) 167 Collateralized mortgage obligations 11,033 (59 ) 2 523,989 (76,110 ) 120 535,022 (76,169 ) 122 Corporate 1,459 (2 ) 1 40,419 (6,571 ) 14 41,878 (6,573 ) 15 Total securities with unrealized losses $ 12,628 $ (62 ) 12 $ 1,392,279 $ (189,513 ) 382 $ 1,404,907 $ (189,575 ) 394 HTM securities: Federal agency $ - $ - - $ 81,560 $ (18,440 ) 4 $ 81,560 $ (18,440 ) 4 Mortgage-backed 11,905 (489 ) 1 194,181 (34,434 ) 33 206,086 (34,923 ) 34 Collateralized mortgage obligation 8,189 (58 ) 1 213,088 (24,614 ) 52 221,277 (24,672 ) 53 State & municipal 4,423 (13 ) 4 181,355 (19,597 ) 205 185,778 (19,610 ) 209 Total securities with unrealized losses $ 24,517 $ (560 ) 6 $ 670,184 $ (97,085 ) 294 $ 694,701 $ (97,645 ) 300 As of December 31, 2023 AFS securities: U.S. treasury $ - $ - - $ 125,024 $ (8,278 ) 8 $ 125,024 $ (8,278 ) 8 Federal agency - - - 214,740 (33,644 ) 16 214,740 (33,644 ) 16 State & municipal - - - 85,528 (9,956 ) 66 85,528 (9,956 ) 66 Mortgage-backed 53 (1 ) 7 421,259 (51,565 ) 156 421,312 (51,566 ) 163 Collateralized mortgage obligations 1,333 (6 ) 2 536,678 (73,351 ) 118 538,011 (73,357 ) 120 Corporate 1,379 (75 ) 1 39,597 (7,391 ) 14 40,976 (7,466 ) 15 Total securities with unrealized losses $ 2,765 $ (82 ) 10 $ 1,422,826 $ (184,185 ) 378 $ 1,425,591 $ (184,267 ) 388 HTM securities: Federal agency $ - $ - - $ 82,216 $ (17,784 ) 4 $ 82,216 $ (17,784 ) 4 Mortgage-backed 12,221 (365 ) 1 201,320 (31,814 ) 33 213,541 (32,179 ) 34 Collateralized mortgage obligations - - - 219,820 (22,929 ) 54 219,820 (22,929 ) 54 State & municipal 14,422 (127 ) 21 171,904 (17,995 ) 189 186,326 (18,122 ) 210 Total securities with unrealized losses $ 26,643 $ (492 ) 22 $ 675,260 $ (90,522 ) 280 $ 701,903 $ (91,014 ) 302 The Company does not believe the AFS securities that were in an unrealized loss position as of March 31, 2024 and December 31, 2023, which consisted of 394 and 388 individual securities, respectively, represented a credit loss impairment. AFS debt securities in unrealized loss positions are evaluated for impairment related to credit losses at least quarterly. As of March 31, 2024 and December 31, 2023, the majority of the AFS securities in an unrealized loss position consisted of debt securities issued by U.S. government agencies or U.S. government-sponsored enterprises that carry the explicit and/or implicit guarantee of the U.S. government, which are widely recognized as “risk-free” and have a long history of zero credit losses. Total gross unrealized losses were primarily attributable to changes in interest rates, relative to when the investment securities were purchased, and not due to the credit quality of the investment securities. The Company does not intend to sell, nor is it more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, which may be at maturity. The Company elected to exclude AIR from the amortized cost basis of debt securities. AIR on AFS debt securities totaled $3.9 million at March 31, 2024 and December 31, 2023, and is excluded from the estimate of credit losses and reported in the other assets None of the Bank’s HTM debt securities were past due or on nonaccrual status as of March 31, 2024 and December 31, 2023. There was no accrued interest reversed against interest income for the three months ended March 31, 2024 or the year ended December 31, 2023 as all securities remained in accrual status. In addition, there were no collateral-dependent HTM debt securities as of March 31, 2024 and December 31, 2023. There was no allowance for credit losses on HTM securities as of March 31, 2024 and December 31, 2023. other assets

Loans

Loans	3 Months Ended
	Mar. 31, 2024
Loans [Abstract]
Loans	5 Loans A summary of loans, net of deferred fees and origination costs, by category is as follows: (In thousands) March 31, 2024 December 31, 2023 Commercial & industrial $ 1,353,446 $ 1,354,248 Commercial real estate 3,646,739 3,626,910 Residential real estate 2,133,289 2,125,804 Home equity 328,673 337,214 Indirect auto 1,190,734 1,130,132 Residential solar 896,147 917,755 Other consumer 139,049 158,650 Total loans $ 9,688,077 $ 9,650,713 Included in the above loans are net deferred loan origination (fees) costs totaling $89.2 million and $98.2 million at March 31, 2024 and December 31, 2023, respectively.

Allowance for Credit Losses and

Allowance for Credit Losses and Credit Quality of Loans	3 Months Ended
	Mar. 31, 2024
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Allowance for Credit Losses and Credit Quality of Loans	6. Allowance for Credit Losses and Credit Quality of Loans The allowance for credit losses totaled $115.3 million at March 31, 2024, compared to $114.4 million at December 31, 2023. The allowance for credit losses as a percentage of loans was 1.19% at March 31, 2024 and December 31, 2023. The Company’s January 1, 2023 adoption of ASU 2022-02, Financial Instruments - CECL Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosure The allowance for credit losses calculation incorporated a 6-quarter forecast period to account for forecast economic conditions under each scenario utilized in the measurement. For periods beyond the 6-quarter forecast, the model reverts to long-term economic conditions over a 4-quarter reversion period on a straight-line basis. The Company considers a baseline, upside and downside economic forecast in measuring the allowance. The quantitative model as of March 31, 2024 incorporated a baseline economic outlook along with an alternative downside scenario sourced from a reputable third-party to accommodate other potential economic conditions in the model. At March 31, 2024, the weightings were 70% and 30% for the baseline and downside economic forecasts, respectively. The baseline outlook reflects an economic environment where the unemployment rate increases slightly from 3.8% to 4.1% during the forecast period. Northeast GDP’s annualized growth (on a quarterly basis) is expected to start the second quarter of 2024 at approximately 3.3% and decrease to 2.8% before increasing to 3.4% by the end of the forecast period. Key assumptions in the baseline economic outlook included the Federal Reserve cutting rates with three 25 basis point cuts at the June, September, and December meetings, the economy remaining at full employment, and continued tapering of the Federal Reserve balance sheet. The alternative downside scenario assumed deteriorated economic conditions from the baseline outlook. Under this scenario, national unemployment rises from 3.8% in the first quarter of 2024 to a peak of 7.7% in the second quarter of 2025. These scenarios and their respective weightings are evaluated at each measurement date and reflect management’s expectations as of March 31, 2024. Additional adjustments were made for factors not incorporated in the forecasts or the model, such as loss rate expectations for certain loan pools, considerations for inflation, and recent trends in asset value indices. Additional monitoring for industry concentrations, loan growth, and policy exceptions was also conducted. The quantitative model as of December 31, 2023 incorporated a baseline economic outlook along with an alternative downside scenario sourced from a reputable third-party to accommodate other potential economic conditions in the model. At December 31, 2023, the weightings were 70% and 30% for the baseline and downside economic forecasts, respectively. The baseline outlook reflected an unemployment rate environment starting at 3.8% and increasing slightly during the forecast period to 4.1%. Northeast GDP’s annualized growth (on a quarterly basis) was expected to start the first quarter of 2024 at approximately 3.7% before decreasing to a low of 2.9% in the third quarter of 2024 and then increasing to 3.8% by the end of the forecast period. Other utilized economic variable forecasts are mixed compared to the prior year, with retail sales improving, business output mixed and housing starts down. Key assumptions in the baseline economic outlook included currently being in a full employment economy, continued tapering of the Federal Reserve balance sheet and the FOMC beginning to cut rates in the second quarter of 2024. The alternative downside scenario assumed deteriorated economic conditions from the baseline outlook. Under this scenario, northeast unemployment increases to a peak of 7.0% in the first quarter of 2025. These scenarios and their respective weightings are evaluated at each measurement date and reflect management’s expectations as of December 31, 2023. Additional qualitative adjustments were made for factors not incorporated in the forecasts or the model, such as loss rate expectations for certain loan pools, considerations for inflation and recent trends in asset value indices. Additional monitoring for industry concentrations, loan growth and policy exceptions was also conducted. There were no loans purchased with credit deterioration during the three months ended March 31, 2024. There were $219.5 million of PCD loans acquired from Salisbury during the year ended December 31, 2023, which resulted in an allowance for credit losses at acquisition of $5.8 million. During the three months ended March 31, 2024, the Company purchased $0.4 million of residential loans at a 7.0% premium with a $4 thousand allowance for credit losses recorded for these loans. During 2023, the Company purchased $3.8 million of residential loans at a 7.0% premium with a $31 thousand allowance for credit losses recorded for these loans. The Company made a policy election to report AIR in the other assets The following tables present the activity in the allowance for credit losses by our portfolio segments: (In thousands) Commercial Loans Consumer Loans Residential Total Balance as of December 31, 2023 $ 45,903 $ 46,427 $ 22,070 $ 114,400 Charge-offs (985 ) (5,581 ) (114 ) (6,680 ) Recoveries 198 1,651 152 2,001 Provision (644 ) 4,922 1,301 5,579 Ending balance as of March 31 2024 $ 44,472 $ 47,419 $ 23,409 $ 115,300 Balance as of January 1, 2023 (after adoption of ASC 2022-02) $ 34,662 $ 50,951 $ 14,539 $ 100,152 Charge-offs (169 ) (5,342 ) (339 ) (5,850 ) Recoveries 541 1,377 121 2,039 Provision 1,006 1,834 1,069 3,909 Ending balance as of March 31 2023 $ 36,040 $ 48,820 $ 15,390 $ 100,250 The allowance for credit losses as of increased compared to the allowance estimates as of primarily due to the slowing of prepayment speed The increase in the allowance for credit losses from to was primarily due to the recording of $14.5 $8.8 million of non-PCD allowance recognized through the provision for loan losses and the $5.8 million of PCD allowance reclassified from loans. Individually Evaluated Loans The threshold for evaluating classified, commercial and commercial real estate loans risk graded substandard or doubtful, and nonperforming loans specifically evaluated for individual credit loss is $1.0 million. As of March 31, 2024, there were two relationships identified to be evaluated for loss on an individual basis which had an amortized cost basis of $17.1 million, with no allowance for credit loss. As of December 31, 2023, the same two relationships were identified to be evaluated for loss on an individual basis which had an amortized cost basis of $17.3 million, with no allowance for credit loss. As of March 31, 2024 and December 31, 2023, there were $17.1 million and $17.3 million, respectively, of loans in nonaccrual that were specifically evaluated for individual expected credit loss without an allowance for credit losses. The following table sets forth information with regard to past due and nonperforming loans by loan segment: (In thousands) 31-60 Days Past Due Accruing 61-90 Days Past Due Accruing Greater Than 90 Days Past Due Accruing Total Past Due Accruing Nonaccrual Current Recorded Total Loans As of March 31 2024 Commercial loans: C&I $ 1,711 $ 750 $ - $ 2,461 $ 3,079 $ 1,398,831 $ 1,404,371 CRE 1,929 64 - 1,993 18,743 3,424,810 3,445,546 Total commercial loans $ 3,640 $ 814 $ - $ 4,454 $ 21,822 $ 4,823,641 $ 4,849,917 Consumer loans: Auto $ 10,376 $ 1,676 $ 1,045 $ 13,097 $ 2,274 $ 1,142,702 $ 1,158,073 Residential solar 3,940 1,362 446 5,748 125 890,274 896,147 Other consumer 2,054 1,158 882 4,094 299 146,372 150,765 Total consumer loans $ 16,370 $ 4,196 $ 2,373 $ 22,939 $ 2,698 $ 2,179,348 $ 2,204,985 Residential $ 3,799 $ 858 $ 227 $ 4,884 $ 10,669 $ 2,617,622 $ 2,633,175 Total loans $ 23,809 $ 5,868 $ 2,600 $ 32,277 $ 35,189 $ 9,620,611 $ 9,688,077 (In thousands) 31-60 Days Past Due Accruing 61-90 Days Past Due Accruing Greater Than 90 Days Past Due Accruing Total Past Due Accruing Nonaccrual Current Recorded Total Loans As of December 31 2023 Commercial loans: C&I $ 414 $ 33 $ 1 $ 448 $ 3,441 $ 1,393,616 $ 1,397,505 CRE 803 835 - 1,638 18,126 3,413,984 3,433,748 Total commercial loans $ 1,217 $ 868 $ 1 $ 2,086 $ 21,567 $ 4,807,600 $ 4,831,253 Consumer loans: Auto $ 10,115 $ 2,011 $ 1,067 $ 13,193 $ 2,106 $ 1,084,143 $ 1,099,442 Residential solar 3,074 1,301 915 5,290 245 912,220 917,755 Other consumer 2,343 1,811 1,124 5,278 215 164,867 170,360 Total consumer loans $ 15,532 $ 5,123 $ 3,106 $ 23,761 $ 2,566 $ 2,161,230 $ 2,187,557 Residential $ 3,836 $ 399 $ 554 $ 4,789 $ 10,080 $ 2,617,034 $ 2,631,903 Total loans $ 20,585 $ 6,390 $ 3,661 $ 30,636 $ 34,213 $ 9,585,864 $ 9,650,713 Credit Quality Indicators The Company has developed an internal loan grading system to evaluate and quantify the Company’s loan portfolio with respect to quality and risk. The system focuses on, among other things, financial strength of borrowers, experience and depth of borrower’s management, primary and secondary sources of repayment, payment history, nature of the business and outlook on particular industries. The internal grading system enables the Company to monitor the quality of the entire loan portfolio on a consistent basis and provide management with an early warning system, which facilitates recognition and response to problem loans and potential problem loans. Commercial Grading System For C&I and CRE loans, the Company uses a grading system that relies on quantifiable and measurable characteristics when available. This includes comparison of financial strength to available industry averages, comparison of transaction factors (loan terms and conditions) to loan policy and comparison of credit history to stated repayment terms and industry averages. Some grading factors are necessarily more subjective such as economic and industry factors, regulatory environment and management. C&I and CRE loans are graded Doubtful, Substandard, Special Mention and Pass. Doubtful A Doubtful loan has a high probability of total or substantial loss, but because of specific pending events that may strengthen the asset, its classification as a loss is deferred. Doubtful borrowers are usually in default, lack adequate liquidity or capital and lack the resources necessary to remain an operating entity. Pending events can include mergers, acquisitions, liquidations, capital injections, the perfection of liens on additional collateral, the valuation of collateral and refinancing. Generally, pending events should be resolved within a relatively short period and the ratings will be adjusted based on the new information. Nonaccrual treatment is required for Doubtful assets because of the high probability of loss. Substandard Substandard loans have a high probability of payment default or they have other well-defined weaknesses. They require more intensive supervision by bank management. Substandard loans are generally characterized by current or expected unprofitable operations, inadequate debt service coverage, inadequate liquidity or marginal capitalization. Repayment may depend on collateral or other credit risk mitigants. For some Substandard loans, the likelihood of full collection of interest and principal may be in doubt and those loans should be placed on nonaccrual. Although Substandard assets in the aggregate will have a distinct potential for loss, an individual asset’s loss potential does not have to be distinct for the asset to be rated Substandard. Special Mention Special Mention loans have potential weaknesses that may, if not checked or corrected, weaken the asset or inadequately protect the Company’s position at some future date. These loans pose elevated risk, but their weakness does not yet justify a Substandard classification. Borrowers may be experiencing adverse operating trends (i.e., declining revenues or margins) or may be struggling with an ill-proportioned balance sheet (i.e., increasing inventory without an increase in sales, high leverage and/or tight liquidity). Adverse economic or market conditions, such as interest rate increases or the entry of a new competitor, may also support a Special Mention rating. Although a Special Mention loan has a higher probability of default than a Pass asset, its default is not imminent. Pass Loans graded as Pass encompass all loans not graded as Doubtful, Substandard or Special Mention. Pass loans are in compliance with loan covenants and payments are generally made as agreed. Pass loans range from superior quality to fair quality. Pass loans also include any portion of a government guaranteed loan, including Paycheck Protection Program loans. Consumer and Residential Grading System Consumer and Residential loans are graded as either Nonperforming or Performing. Nonperforming Nonperforming loans are loans that are (1) over 90 days past due and interest is still accruing or (2) on nonaccrual status. Performing All loans not meeting any of the above criteria are considered Performing. The following tables illustrate the Company’s credit quality by loan class by vintage and includes gross charge-offs by loan class by vintage. Included in other consumer gross charge-offs for the three months ended March 31, 2024, the Company recorded $0.2 million in overdrawn deposit accounts reported as 2023 originations. Included in other consumer gross charge-offs for the year ended December 31, 2023, the Company recorded $0.2 million in overdrawn deposit accounts reported as 2022 originations and $0.8 million in overdrawn deposit accounts reported as 2023 originations. (In thousands) 2024 2023 2022 2021 2020 Prior Revolving Loans Amortized Cost Basis Revolving Loans Converted to Term Total As of March 31 2024 C&I By internally assigned grade: Pass $ 60,820 $ 214,985 $ 243,619 $ 231,577 $ 146,409 $ 129,310 $ 318,078 $ 2,585 $ 1,347,383 Special mention - 1,795 2,802 378 3,845 1,812 15,946 251 26,829 Substandard - 2,934 3,154 1,885 289 6,845 14,880 127 30,114 Doubtful - 21 1 19 - 4 - - 45 Total C&I $ 60,820 $ 219,735 $ 249,576 $ 233,859 $ 150,543 $ 137,971 $ 348,904 $ 2,963 $ 1,404,371 Current-period gross charge-offs $ - $ (9 ) $ (900 ) $ - $ - $ (76 ) $ - $ - $ (985 ) CRE By internally assigned grade: Pass $ 81,048 $ 362,660 $ 492,661 $ 546,787 $ 449,533 $ 1,013,118 $ 308,977 $ 37,243 $ 3,292,027 Special mention - 3,602 5,971 7,842 3,875 28,841 3,547 - 53,678 Substandard - - 726 17,961 1,132 61,499 1,542 16,981 99,841 Total CRE $ 81,048 $ 366,262 $ 499,358 $ 572,590 $ 454,540 $ 1,103,458 $ 314,066 $ 54,224 $ 3,445,546 Current-period gross charge-offs $ - $ - $ - $ - $ - $ - $ - $ - $ - Auto By payment activity: Performing $ 175,451 $ 430,001 $ 331,202 $ 138,915 $ 36,140 $ 43,045 $ - $ - $ 1,154,754 Nonperforming 29 1,014 1,171 724 94 287 - - 3,319 Total auto $ 175,480 $ 431,015 $ 332,373 $ 139,639 $ 36,234 $ 43,332 $ - $ - $ 1,158,073 Current-period gross charge-offs $ - $ (274 ) $ (493 ) $ (226 ) $ (12 ) $ (122 ) $ - $ - $ (1,127 ) Residential solar By payment activity: Performing $ 1,365 $ 149,789 $ 422,422 $ 176,158 $ 63,222 $ 82,620 $ - $ - $ 895,576 Nonperforming - - 432 76 - 63 - - 571 Total residential solar $ 1,365 $ 149,789 $ 422,854 $ 176,234 $ 63,222 $ 82,683 $ - $ - $ 896,147 Current-period gross charge-offs $ - $ (53 ) $ (910 ) $ (136 ) $ - $ (196 ) $ - $ - $ (1,295 ) Other consumer By payment activity: Performing $ 5,600 $ 10,559 $ 22,720 $ 47,947 $ 18,029 $ 25,681 $ 19,015 $ 33 $ 149,584 Nonperforming - 5 184 650 39 295 1 7 1,181 Total other consumer $ 5,600 $ 10,564 $ 22,904 $ 48,597 $ 18,068 $ 25,976 $ 19,016 $ 40 $ 150,765 Current-period gross charge-offs $ - $ (250 ) $ (811 ) $ (1,453 ) $ (364 ) $ (281 ) $ - $ - $ (3,159 ) Residential By payment activity: Performing $ 39,693 $ 258,154 $ 336,357 $ 438,007 $ 273,451 $ 1,006,816 $ 255,582 $ 14,219 $ 2,622,279 Nonperforming - 626 825 1,605 272 7,568 - - 10,896 Total residential $ 39,693 $ 258,780 $ 337,182 $ 439,612 $ 273,723 $ 1,014,384 $ 255,582 $ 14,219 $ 2,633,175 Current-period gross charge-offs $ - $ - $ - $ - $ - $ (114 ) $ - $ - $ (114 ) Total loans $ 364,006 $ 1,436,145 $ 1,864,247 $ 1,610,531 $ 996,330 $ 2,407,804 $ 937,568 $ 71,446 $ 9,688,077 Current-period gross charge-offs $ - $ (586 ) $ (3,114 ) $ (1,815 ) $ (376 ) $ (789 ) $ - $ - $ (6,680 ) (In thousands) 2023 2022 2021 2020 2019 Prior Revolving Loans Amortized Cost Basis Revolving Loans Converted to Term Total As of December 31, 2023 C&I By internally assigned grade: Pass $ 229,249 $ 270,796 $ 241,993 $ 158,051 $ 74,469 $ 63,826 $ 299,248 $ 2,923 $ 1,340,555 Special mention 420 1,672 277 3,524 87 1,854 19,489 - 27,323 Substandard 1,496 2,461 1,609 282 2,266 5,632 14,266 1,607 29,619 Doubtful - 1 2 - 4 1 - - 8 Total C&I $ 231,165 $ 274,930 $ 243,881 $ 161,857 $ 76,826 $ 71,313 $ 333,003 $ 4,530 $ 1,397,505 Current-period gross charge-offs $ (24 ) $ (3,021 ) $ (5 ) $ (86 ) $ - $ (600 ) $ - $ - $ (3,736 ) CRE By internally assigned grade: Pass $ 353,161 $ 518,201 $ 561,897 $ 452,110 $ 327,804 $ 739,189 $ 294,039 $ 33,705 $ 3,280,106 Special mention 3,577 4,472 10,711 7,055 9,967 39,460 2,970 - 78,212 Substandard 370 731 21,807 1,146 2,996 37,418 10,962 - 75,430 Total CRE $ 357,108 $ 523,404 $ 594,415 $ 460,311 $ 340,767 $ 816,067 $ 307,971 $ 33,705 $ 3,433,748 Current-period gross charge-offs $ - $ - $ - $ - $ (114 ) $ (304 ) $ - $ - $ (418 ) Auto By payment activity: Performing $ 474,369 $ 363,516 $ 157,251 $ 42,644 $ 45,406 $ 13,071 $ 12 $ - $ 1,096,269 Nonperforming 532 1,241 830 190 306 74 - - 3,173 Total auto $ 474,901 $ 364,757 $ 158,081 $ 42,834 $ 45,712 $ 13,145 $ 12 $ - $ 1,099,442 Current-period gross charge-offs $ (102 ) $ (1,183 ) $ (1,066 ) $ (340 ) $ (301 ) $ (295 ) $ - $ - $ (3,287 ) Residential solar By payment activity: Performing $ 155,425 $ 430,855 $ 178,839 $ 65,382 $ 46,554 $ 39,540 $ - $ - $ 916,595 Nonperforming - 837 205 18 47 53 - - 1,160 Total residential solar $ 155,425 $ 431,692 $ 179,044 $ 65,400 $ 46,601 $ 39,593 $ - $ - $ 917,755 Current-period gross charge-offs $ (150 ) $ (1,930 ) $ (923 ) $ (45 ) $ (558 ) $ (345 ) $ - $ - $ (3,951 ) Other consumer By payment activity: Performing $ 13,089 $ 27,394 $ 57,876 $ 21,087 $ 14,548 $ 15,964 $ 19,042 $ 21 $ 169,021 Nonperforming - 244 685 144 56 161 4 45 1,339 Total other consumer $ 13,089 $ 27,638 $ 58,561 $ 21,231 $ 14,604 $ 16,125 $ 19,046 $ 66 $ 170,360 Current-period gross charge-offs $ (885 ) $ (3,744 ) $ (7,511 ) $ (1,329 ) $ (832 ) $ (568 ) $ - $ - $ (14,869 ) Residential By payment activity: Performing $ 212,799 $ 366,860 $ 453,206 $ 267,845 $ 167,860 $ 876,563 $ 260,836 $ 15,300 $ 2,621,269 Nonperforming 134 430 1,121 385 591 7,460 - 513 10,634 Total residential $ 212,933 $ 367,290 $ 454,327 $ 268,230 $ 168,451 $ 884,023 $ 260,836 $ 15,813 $ 2,631,903 Current-period gross charge-offs $ - $ - $ (81 ) $ (30 ) $ - $ (406 ) $ - $ - $ (517 ) Total loans $ 1,444,621 $ 1,989,711 $ 1,688,309 $ 1,019,863 $ 692,961 $ 1,840,266 $ 920,868 $ 54,114 $ 9,650,713 Current-period gross charge-offs $ (1,161 ) $ (9,878 ) $ (9,586 ) $ (1,830 ) $ (1,805 ) $ (2,518 ) $ - $ - $ (26,778 ) Allowance for Credit Losses on Off-Balance Sheet Credit Exposures The allowance for losses on unfunded commitments totaled $4.7 million as March 31, 2024, compared to $5.1 million as of December 31, 2023. Loan Modifications to Borrowers Experiencing Financial Difficulties When the Company modifies a loan with financial difficulty, such modifications generally include one or a combination of the following: an extension of the maturity date at a stated rate of interest lower than the current market rate for new debt with similar risk; a change in scheduled payment amount; or principal forgiveness. The following table shows the amortized cost basis at the end of the reporting period of the loans modified to borrowers experiencing financial difficulty, disaggregated by class of financing receivable and type of concession granted: Three Months Ended March 31, 2024 Term Extension (Dollars in thousands) Amortized Cost % of Total Class of Financing Receivables Residential $ 294 0.011 % Total $ 294 Three Months Ended March 31, 2023 Term Extension (Dollars in thousands) Amortized Cost % of Total Class of Financing Receivables Residential $ 43 0.002 % Total $ 43 The following table describes the financial effect of the modifications made to borrowers experiencing financial difficulties: Three Months Ended March 31, 2024 Loan Type Term Extension Residential Added a weighted-average 7.4 years to the life of loans, which reduced monthly payment amounts for the borrowers. Three Months Ended March 31, 2023 Loan Type Term Extension Residential Added a weighted-average 18 years to the life of loans, which reduced monthly payment amounts for the borrowers. There were no financing receivables that had a payment default during the three months ended March 31, 2024 and 2023, that were modified to borrowers experiencing financial difficulty that were modified in the twelve months prior to that default. The Payment Status (Amortized Cost Basis) (In thousands) Current 31-60 Days Past Due 61-90 Days Past Due Greater than 90 Days Past Due As of March 31, 2024 Loan Type Residential $ 863 $ - $ - $ 29 Total $ 863 $ - $ - $ 29

Short-Term Borrowings

Short-Term Borrowings	3 Months Ended
	Mar. 31, 2024
Short-Term Borrowings [Abstract]
Short-Term Borrowings	7. Short-Term Borrowings In addition to the liquidity provided by balance sheet cash flows, liquidity must also be supplemented with additional sources such as credit lines from correspondent banks as well as borrowings from the FHLB and the Federal Reserve Bank. Other funding alternatives may also be appropriate from time to time, including wholesale and retail repurchase agreements and brokered CD accounts. Information related to short-term borrowings is summarized as follows: (In thousands) March 31, 2024 December 31, 2023 Federal funds purchased $ 78,000 $ - Securities sold under repurchase agreements 86,134 93,651 Other short-term borrowings 103,000 293,000 Total short-term borrowings $ 267,134 $ 386,651 See Note 4 for additional information regarding securities pledged as collateral for securities sold under the repurchase agreements.

Defined Benefit Post-Retirement

Defined Benefit Post-Retirement Plans	3 Months Ended
	Mar. 31, 2024
Defined Benefit Post-Retirement Plans [Abstract]
Defined Benefit Post-Retirement Plans	8. Defined Benefit Post-Retirement Plans The Company has a qualified, noncontributory, defined benefit pension plan (the “Plan”) covering substantially all of its employees at March 31, 2024. Benefits paid from the Plan are based on age, years of service, compensation and social security benefits and are determined in accordance with defined formulas. The Company’s policy is to fund the Plan in accordance with Employee Retirement Income Security Act of 1974 standards. Assets of the Plan are invested in publicly traded stocks, bonds and mutual funds. In addition to the Plan, the Company provides supplemental employee retirement plans to certain current and former executives. These supplemental employee retirement plans and the Plan are collectively referred to herein as “Pension Benefits.” In addition, the Company provides certain health care benefits for retired employees. Benefits were accrued over the employees’ active service period. Only employees that were employed by the Company on or before January 1, 2000 are eligible to receive post-retirement health care benefits. These post-retirement benefits are referred to herein as “Other Benefits.” Accounting standards require an employer to: (1) recognize the overfunded or underfunded status of defined benefit post-retirement plans, which is measured as the difference between plan assets at fair value and the benefit obligation, as an asset or liability in its balance sheet; (2) recognize changes in that funded status in the year in which the changes occur through comprehensive income; and (3) measure the defined benefit plan assets and obligations as of the date of its year-end balance sheet. The Company made no voluntary contributions to the Pension Benefits and Other Benefits plans during the three months ended March 31, 2024 and 2023. The components of expense for Pension Benefits and Other Benefits are set forth below: Pension Benefits Other Benefits Three Months Ended March 31, Three Months Ended March 31, (In thousands) 2024 2023 2024 2023 Components of net periodic (benefit) cost: Service cost $ 514 $ 482 $ 1 $ 1 Interest cost 1,005 1,010 55 56 Expected return on plan assets (1,983 ) (1,853 ) - - Net amortization 453 670 (1 ) (21 ) Total net periodic (benefit) cost $ (11 ) $ 309 $ 55 $ 36 The service cost component of net periodic (benefit) cost is included in Salaries and Employee Benefits and the interest cost, expected return on plan assets and net amortization components are included in Other Noninterest Expense on the unaudited interim consolidated statements of income.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	9. Earnings Per Share Basic EPS excludes dilution and is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity (such as the Company’s dilutive stock options and restricted stock units). The following is a reconciliation of basic and diluted EPS for the periods presented in the unaudited interim consolidated statements of income: Three Months Ended March 31, (In thousands, except per share data) 2024 2023 Basic EPS: Weighted average common shares outstanding 47,148 42,894 Net income available to common stockholders $ 33,823 $ 33,658 Basic EPS $ 0.72 $ 0.78 Diluted EPS: Weighted average common shares outstanding 47,148 42,894 Dilutive effect of common stock options and restricted stock 222 232 Weighted average common shares and common share equivalents 47,370 43,126 Net income available to common stockholders $ 33,823 $ 33,658 Diluted EPS $ 0.71 $ 0.78 There was a nominal number of weighted average stock options outstanding for the three months ended March 31, 2024 and March 31, 2023, that were not considered in the calculation of diluted EPS since the stock options’ exercise prices were greater than the average market price during these periods.

Reclassification Adjustments Ou

Reclassification Adjustments Out of Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2024
Reclassification Adjustments Out of Other Comprehensive Income (Loss) [Abstract]
Reclassification Adjustments Out of Other Comprehensive Income (Loss)	10. Reclassification Adjustments Out of Other Comprehensive Income (Loss) The following table summarizes the reclassification adjustments out of AOCI: Detail About AOCI Components Amount Reclassified from AOCI Affected Line Item in the Consolidated Statements of Comprehensive Income (Loss) Three Months Ended (In thousands) March 31, 2024 March 31, 2023 AFS securities: Losses on AFS securities $ - $ 5,000 Net securities (gains) losses Amortization of unrealized gains related to securities transfer 96 114 Interest income Tax effect $ (24 ) $ (1,278 ) Income tax (benefit) Net of tax $ 72 $ 3,836 Pension and other benefits: Amortization of net losses $ 454 $ 640 Other noninterest expense Amortization of prior service costs (2 ) 9 Other noninterest expense Tax effect $ (113 ) $ (163 ) Income tax (benefit) Net of tax $ 339 $ 486 Total reclassifications, net of tax $ 411 $ 4,322

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities [Abstract]
Derivative Instruments and Hedging Activities	11. Derivative Instruments and Hedging Activities The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, primarily by managing the amount, sources and duration of its assets and liabilities and through the use of derivative instruments. Specifically, the Company may enter into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. Generally, the Company may use derivative financial instruments to manage differences in the amount, timing and duration of the Company’s known or expected cash receipts and its known or expected cash payments. Currently, the Company has interest rate derivatives that result from a service provided to certain qualifying customers and, therefore, are not used to manage interest rate risk in the Company’s assets or liabilities. The Company manages a matched book with respect to its derivative instruments in order to minimize its net risk exposure resulting from such transactions. Derivatives Not Designated as Hedging Instruments The Company enters into interest rate swaps to facilitate customer transactions and meet their financing needs. These swaps are considered derivatives, but are not designated in hedging relationships. These instruments have interest rate and credit risk associated with them. To mitigate the interest rate risk, the Company enters into offsetting interest rate swaps with counterparties. The counterparty swaps are also considered derivatives and are also not designated in hedging relationships. Interest rate swaps are recorded within other assets or other liabilities on the consolidated balance sheets at their estimated fair value. Changes to the fair value of assets and liabilities arising from these derivatives are included, net, in other operating income in the consolidated statements of incom e. The Company is subject to over-the-counter derivative clearing requirements, which require certain derivatives to be cleared through central clearing houses. Accordingly, the Company clears certain derivative transactions through the CME. The CME requires the Company to post initial and variation margin payments to mitigate the risk of non-payment, the latter of which is received or paid daily based on the net asset or liability position of the contracts. A daily settlement occurs through the CME for changes in the fair value of centrally cleared derivatives. Not all of the derivatives are required to be cleared through the daily clearing agent. As a result, the total fair values of loan level derivative assets and liabilities recognized on the Company’s financial statements are not equal and offsetting. In 2017, the U.K. Financial Conduct Authority announced its intention to stop compelling banks to submit rates for the calculation of LIBOR after 2021. In 2022, the Federal Reserve adopted a final rule implementing the Adjustable Interest Rate (LIBOR) Act by identifying benchmark rates based on SOFR that replaced LIBOR in certain financial contracts after June 30, 2023. In 2023, the Company transitioned all of its financial instruments to an alternative benchmark rate. As . The following table summarizes the derivatives outstanding: (In thousands) Notional Amount Balance Sheet Location Fair Value Notional Amount Balance Sheet Location Fair Value As of March 31 2024 Derivatives not designated as hedging instruments Interest rate derivatives $ 1,330,997 Other assets $ 114,205 $ 1,330,997 Other liabilities $ 114,101 Risk participation agreements 71,511 Other assets 84 15,571 Other liabilities 3 Total derivatives not designated as hedging instruments $ 114,289 $ 114,104 Netting adjustments (1) 24,321 - Net derivatives in the balance sheet $ 89,968 $ 114,104 Derivatives not offset on the balance sheet $ 1,924 $ 1,924 Cash collateral (2) - - Net derivative amounts $ 88,044 $ 112,180 As of December 31, 2023 Derivatives not designated as hedging instruments Interest rate derivatives $ 1,303,711 Other assets $ 95,972 $ 1,303,711 Other liabilities $ 95,869 Risk participation agreements 62,112 Other assets 19 16,146 Other liabilities 6 Total derivatives not designated as hedging instruments $ 95,991 $ 95,875 Netting adjustments (1) 20,849 - Net derivatives in the balance sheet $ 75,142 $ 95,875 Derivatives not offset on the balance sheet $ 2,930 $ 2,930 Cash collateral (2) - - Net derivative amounts $ 72,212 $ 92,945 (1) Netting adjustments represents the amounts recorded to convert derivatives assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance on the settle to market rules for cleared derivatives. The CME legally characterizes the variation margin posted between counterparties as settlements of the outstanding derivative contracts instead of cash collateral. (2) Cash collateral represents the amount that cannot be used to offset our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The other collateral consists of securities and is exchanged under bilateral collateral and master netting agreements that allow us to offset the net derivative position with the related collateral. The application of the other collateral cannot reduce the net derivative position below zero. Therefore, excess other collateral, if any, is not reflected above. The following table indicates the gain or loss recognized in income on derivatives not designated as a hedging relationship: Three Months Ended March 31, (In thousands) 2024 2023 Derivatives not designated as hedging instruments: Increase in other income $ 75 $ 7

Fair Value Measurements and Fai

Fair Value Measurements and Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2024
Fair Value Measurements and Fair Value of Financial Instruments [Abstract]
Fair Value Measurements and Fair Value of Financial Instruments	12. Fair Value Measurements and Fair Value of Financial Instruments G AAP states that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value measurements are not adjusted for transaction costs. A fair value hierarchy exists within GAAP that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below: Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 - Quoted prices for similar assets or liabilities in active markets, quoted prices in markets that are not active or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability; and Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The types of instruments valued based on quoted market prices in active markets include most U.S. government and agency securities, many other sovereign government obligations, liquid mortgage products, active listed equities and most money market securities. Such instruments are generally classified within Level 1 or Level 2 of the fair value hierarchy. The Company does not adjust the quoted prices for such instruments. The types of instruments valued based on quoted prices in markets that are not active, broker or dealer quotations or quote from alternative pricing sources with reasonable levels of price transparency include most investment-grade and high-yield corporate bonds, less liquid mortgage products, less liquid agency securities, less liquid listed equities, state, municipal and provincial obligations and certain physical commodities. Such instruments are generally classified within Level 2 of the fair value hierarchy. Certain common equity securities are reported at fair value utilizing Level 1 inputs (exchange quoted prices). Other investment securities are reported at fair value utilizing Level 1 and Level 2 inputs. The prices for Level 2 instruments are obtained through an independent pricing service or dealer market participants with whom the Company has historically transacted both purchases and sales of investment securities. Prices obtained from these sources include prices derived from market quotations and matrix pricing. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. Management reviews the methodologies used by its third-party providers in pricing the securities. Level 3 is for positions that are not traded in active markets or are subject to transfer restrictions. Valuations are adjusted to reflect illiquidity and/or non-transferability and such adjustments are generally based on available market evidence. In the absence of such evidence, management’s best estimate will be used. Management’s best estimate consists of both internal and external support on certain Level 3 investments. Subsequent to inception, management only changes Level 3 inputs and assumptions when corroborated by evidence such as transactions in similar instruments, completed or pending third-party transactions in the underlying investment or comparable entities, subsequent rounds of financing, recapitalizations and other transactions across the capital structure, offerings in the equity or debt markets and changes in financial ratios or cash flow The following tables set forth the Company’s financial assets and liabilities measured on a recurring basis that were accounted for at fair value. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement: (In thousands) Level 1 Level 2 Level 3 March 31, 2024 Assets: AFS securities: U.S. treasury $ 124,683 $ - $ - $ 124,683 Federal agency - 213,304 - 213,304 State & municipal - 86,033 - 86,033 Mortgage-backed - 405,547 - 405,547 Collateralized mortgage obligations - 547,026 - 547,026 Corporate - 41,878 - 41,878 Total AFS securities $ 124,683 $ 1,293,788 $ - $ 1,418,471 Equity securities 38,470 1,000 - 39,470 Derivatives - 89,968 - 89,968 Total $ 163,153 $ 1,384,756 $ - $ 1,547,909 Liabilities: Derivatives $ - $ 114,104 $ - $ 114,104 Total $ - $ 114,104 $ - $ 114,104 (In thousands) Level 1 Level 2 Level 3 December 31, 2023 Assets: AFS securities: U.S. treasury $ 125,024 $ - $ - $ 125,024 Federal agency - 214,740 - 214,740 State & municipal - 86,306 - 86,306 Mortgage-backed - 422,268 - 422,268 Collateralized mortgage obligations - 541,544 - 541,544 Corporate - 40,976 - 40,976 Total AFS securities $ 125,024 $ 1,305,834 $ - $ 1,430,858 Equity securities 36,591 1,000 - 37,591 Derivatives - 75,142 - 75,142 Total $ 161,615 $ 1,381,976 $ - $ 1,543,591 Liabilities: Derivatives $ - $ 95,875 $ - $ 95,875 Total $ - $ 95,875 $ - $ 95,875 GAAP requires disclosure of assets and liabilities measured and recorded at fair value on a non-recurring basis such as goodwill, loans held for sale, other real estate owned, collateral-dependent loans individually evaluated for expected credit losses and HTM securities. There were no loans individually evaluated for expected credit losses where the amortized cost was adjusted to fair value as of March 31, 2024 and December 31, 2023, respectively. The Company uses the fair value of underlying collateral, less costs to sell, to estimate the allowance for credit losses for individually evaluated collateral dependent loans. The appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses ranging from 10% to 50% The following table sets forth information with regard to estimated fair values of financial instruments. This table excludes financial instruments for which the carrying amount approximates fair value. Financial instruments for which the fair value approximates carrying value include cash and cash equivalents, AFS securities, equity securities, accrued interest receivable, non-maturity deposits, short-term borrowings, accrued interest payable and derivatives. March 31, 2024 December 31, 2023 (In thousands) Fair Value Hierarchy Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets: HTM securities 2 $ 890,863 $ 793,319 $ 905,267 $ 814,524 Net loans 3 9,576,040 9,173,300 9,539,684 9,216,162 Financial liabilities: Time deposits 2 $ 1,368,136 $ 1,348,934 $ 1,324,709 $ 1,285,999 Long-term debt 2 29,759 29,315 29,796 29,416 Subordinated debt 1 120,628 116,563 120,380 113,757 Junior subordinated debt 2 101,196 103,202 101,196 102,337 Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument. Because no market exists for a significant portion of the Company’s financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates. Fair value estimates are based on existing on and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. For example, the Company has a substantial wealth operation that contributes net fee income annually. The wealth management operation is not considered a financial instrument and its value has not been incorporated into the fair value estimates. Other significant assets and liabilities include the benefits resulting from the low-cost funding of deposit liabilities as compared to the cost of borrowing funds in the market and premises and equipment. In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in the estimate of fair value. HTM Securities The fair value of the Company’s HTM securities is primarily measured using information from a third-party pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. Net Loans Net loans include portfolio loans and loans held for sale. Loans were first segregated by type and then further segmented into fixed and variable rate and loan quality categories. Expected future cash flows were projected based on contractual cash flows, adjusted for estimated prepayments, and those expected future cash flows also includes credit risk, illiquidity risk and other market factors to calculate the exit price fair value in accordance with ASC 820. Time Deposits The fair value of time deposits was estimated using a discounted cash flow approach that applies prevailing market interest rates for similar maturity instruments. The fair values of the Company’s time deposit liabilities do not take into consideration the value of the Company’s long-term relationships with depositors, which may have significant value. Long-Term Debt The fair value of long-term debt was estimated using a discounted cash flow approach that applies prevailing market interest rates for similar maturity instruments. Subordinated Debt The fair value of subordinated debt has been measured using the observable market price as of the period reported. Junior Subordinated Debt The fair value of junior subordinated debt has been estimated using a discounted cash flow analysis.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies The Company is a party to certain financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit, unused lines of credit, standby letters of credit and certain agricultural real estate loans sold to investors with recourse, with the sold portion having a government guarantee that is assignable back to the Company upon repurchase of the loan in the event of default. The Company’s exposure to credit loss in the event of nonperformance by the other party to the commitments to extend credit, unused lines of credit, standby letters of credit and loans sold with recourse is represented by the contractual amount of those instruments. The credit risk associated with commitments to extend credit and standby and commercial letters of credit is essentially the same as that involved with extending loans to customers and is subject to normal credit policies. Collateral may be obtained based on management’s assessment of the customer’s creditworthiness. Commitments to extend credit and unused lines of credit totaled $2.73 billion at at Since many loan commitments, standby letters of credit and guarantees and indemnification contracts expire without being funded in whole or in part, the contract amounts are not necessarily indicative of future cash flows. The Company does not issue any guarantees that would require liability-recognition or disclosure, other than its standby letters of credit. The Company guarantees the obligations or performance of customers by issuing standby letters of credit to third-parties. These standby letters of credit are generally at March 31, 2024 s of March 31, 2024 and December 31, 2023

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Insider Trading Arrangements [Line Items]
Rule 10b5-1 Arrangement Adopted [Flag]	false
Non-Rule 10b5-1 Arrangement Adopted [Flag]	false
Rule 10b5-1 Arrangement Terminated [Flag]	false
Non-Rule 10b5-1 Arrangement Terminated [Flag]	false

Description of Business (Polici

Description of Business (Policies)	3 Months Ended
	Mar. 31, 2024
Description of Business [Abstract]
Nature of Operations	NBT Bancorp Inc. is a registered financial holding company incorporated in the state of Delaware in 1986, with its principal headquarters located in Norwich, New York. The principal assets of NBT Bancorp Inc. (collectively, the “Trusts”) NBT Bancorp Inc. The Company’s business, primarily conducted through the Bank, consists of providing commercial banking, retail banking and wealth management services primarily to customers in its market area, which includes upstate New York, northeastern Pennsylvania, southern New Hampshire, western Massachusetts, Vermont, southern Maine and central and northwestern

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim consolidated financial statements include the accounts of NBT Bancorp Inc. and its wholly-owned subsidiaries: the Bank, NBT Financial and NBT Holdings. In the opinion of management, the interim data includes all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the results for the interim periods in accordance with GAAP and in accordance with the instructions to Quarterly Report on Form 10-Q and Article 10 of Regulation S-X as promulgated by the SEC. Accordingly, the consolidated financial statements do not include all of the information and notes necessary for complete financial statements in conformity with GAAP. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s 2023 Annual Report on Form 10-K. 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. All material intercompany transactions have been eliminated in consolidation. Amounts previously reported in the consolidated financial statements are reclassified whenever necessary to conform to current period presentation. The Company has evaluated subsequent events for potential recognition and/or disclosure and there were none identified.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results may differ from those estimates and such differences could be material to the financial statements. Estimates associated with the allowance for credit losses, pension accounting, provision for income taxes, fair values of financial instruments and status of contingencies are particularly susceptible to material change in the near term.

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2024
Recent Accounting Pronouncements [Abstract]
Accounting Standards Issued Not Yet Adopted	Accounting Standards Issued Not Yet Adopted In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements , other than to meet the new disclosure requirements, In November 2023, the FASB issued ASU 2023-07, Improvements to Reportable Segment Disclosures In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures , that addresses requests for improved income tax disclosures from investors, lenders, creditors and other allocators of capital that use the financial statements to make capital allocation decisions. The ASU requires enhanced disclosures primarily related to existing rate reconciliation and income taxes paid information to help investors better assess how the Company’s operations and related tax risks and tax planning and operational opportunities affect the Company’s tax rate and prospects for future cash flows. The ASU 2023-09 improves the transparency of income tax disclosures. The amendments in this ASU are effective for the Company on January 1, 2025 and should be applied on a prospective basis. Retrospective application and early adoption are permitted. The adoption, other than to meet the new disclosure requirements, is not expected to have a material impact on the consolidated financial statements.

Securities (Policies)

Securities (Policies)	3 Months Ended
	Mar. 31, 2024
Securities [Abstract]
Investment, Policy	The Company does not believe the AFS securities that were in an unrealized loss position as of March 31, 2024 and December 31, 2023, which consisted of 394 and 388 individual securities, respectively, represented a credit loss impairment. AFS debt securities in unrealized loss positions are evaluated for impairment related to credit losses at least quarterly. As of March 31, 2024 and December 31, 2023, the majority of the AFS securities in an unrealized loss position consisted of debt securities issued by U.S. government agencies or U.S. government-sponsored enterprises that carry the explicit and/or implicit guarantee of the U.S. government, which are widely recognized as “risk-free” and have a long history of zero credit losses. Total gross unrealized losses were primarily attributable to changes in interest rates, relative to when the investment securities were purchased, and not due to the credit quality of the investment securities. The Company does not intend to sell, nor is it more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, which may be at maturity. The Company elected to exclude AIR from the amortized cost basis of debt securities. AIR on AFS debt securities totaled $3.9 million at March 31, 2024 and December 31, 2023, and is excluded from the estimate of credit losses and reported in the other assets None of the Bank’s HTM debt securities were past due or on nonaccrual status as of March 31, 2024 and December 31, 2023. There was no accrued interest reversed against interest income for the three months ended March 31, 2024 or the year ended December 31, 2023 as all securities remained in accrual status. In addition, there were no collateral-dependent HTM debt securities as of March 31, 2024 and December 31, 2023. There was no allowance for credit losses on HTM securities as of March 31, 2024 and December 31, 2023. other assets

Allowance for Credit Losses a_2

Allowance for Credit Losses and Credit Quality of Loans (Policies)	3 Months Ended
	Mar. 31, 2024
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Allowance for Credit Losses	The allowance for credit losses totaled $115.3 million at March 31, 2024, compared to $114.4 million at December 31, 2023. The allowance for credit losses as a percentage of loans was 1.19% at March 31, 2024 and December 31, 2023. The Company’s January 1, 2023 adoption of ASU 2022-02, Financial Instruments - CECL Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosure The allowance for credit losses calculation incorporated a 6-quarter forecast period to account for forecast economic conditions under each scenario utilized in the measurement. For periods beyond the 6-quarter forecast, the model reverts to long-term economic conditions over a 4-quarter reversion period on a straight-line basis. The Company considers a baseline, upside and downside economic forecast in measuring the allowance. The quantitative model as of March 31, 2024 incorporated a baseline economic outlook along with an alternative downside scenario sourced from a reputable third-party to accommodate other potential economic conditions in the model. At March 31, 2024, the weightings were 70% and 30% for the baseline and downside economic forecasts, respectively. The baseline outlook reflects an economic environment where the unemployment rate increases slightly from 3.8% to 4.1% during the forecast period. Northeast GDP’s annualized growth (on a quarterly basis) is expected to start the second quarter of 2024 at approximately 3.3% and decrease to 2.8% before increasing to 3.4% by the end of the forecast period. Key assumptions in the baseline economic outlook included the Federal Reserve cutting rates with three 25 basis point cuts at the June, September, and December meetings, the economy remaining at full employment, and continued tapering of the Federal Reserve balance sheet. The alternative downside scenario assumed deteriorated economic conditions from the baseline outlook. Under this scenario, national unemployment rises from 3.8% in the first quarter of 2024 to a peak of 7.7% in the second quarter of 2025. These scenarios and their respective weightings are evaluated at each measurement date and reflect management’s expectations as of March 31, 2024. Additional adjustments were made for factors not incorporated in the forecasts or the model, such as loss rate expectations for certain loan pools, considerations for inflation, and recent trends in asset value indices. Additional monitoring for industry concentrations, loan growth, and policy exceptions was also conducted. The quantitative model as of December 31, 2023 incorporated a baseline economic outlook along with an alternative downside scenario sourced from a reputable third-party to accommodate other potential economic conditions in the model. At December 31, 2023, the weightings were 70% and 30% for the baseline and downside economic forecasts, respectively. The baseline outlook reflected an unemployment rate environment starting at 3.8% and increasing slightly during the forecast period to 4.1%. Northeast GDP’s annualized growth (on a quarterly basis) was expected to start the first quarter of 2024 at approximately 3.7% before decreasing to a low of 2.9% in the third quarter of 2024 and then increasing to 3.8% by the end of the forecast period. Other utilized economic variable forecasts are mixed compared to the prior year, with retail sales improving, business output mixed and housing starts down. Key assumptions in the baseline economic outlook included currently being in a full employment economy, continued tapering of the Federal Reserve balance sheet and the FOMC beginning to cut rates in the second quarter of 2024. The alternative downside scenario assumed deteriorated economic conditions from the baseline outlook. Under this scenario, northeast unemployment increases to a peak of 7.0% in the first quarter of 2025. These scenarios and their respective weightings are evaluated at each measurement date and reflect management’s expectations as of December 31, 2023. Additional qualitative adjustments were made for factors not incorporated in the forecasts or the model, such as loss rate expectations for certain loan pools, considerations for inflation and recent trends in asset value indices. Additional monitoring for industry concentrations, loan growth and policy exceptions was also conducted. The Company made a policy election to report AIR in the other assets Credit Quality Indicators The Company has developed an internal loan grading system to evaluate and quantify the Company’s loan portfolio with respect to quality and risk. The system focuses on, among other things, financial strength of borrowers, experience and depth of borrower’s management, primary and secondary sources of repayment, payment history, nature of the business and outlook on particular industries. The internal grading system enables the Company to monitor the quality of the entire loan portfolio on a consistent basis and provide management with an early warning system, which facilitates recognition and response to problem loans and potential problem loans. Commercial Grading System For C&I and CRE loans, the Company uses a grading system that relies on quantifiable and measurable characteristics when available. This includes comparison of financial strength to available industry averages, comparison of transaction factors (loan terms and conditions) to loan policy and comparison of credit history to stated repayment terms and industry averages. Some grading factors are necessarily more subjective such as economic and industry factors, regulatory environment and management. C&I and CRE loans are graded Doubtful, Substandard, Special Mention and Pass. Doubtful A Doubtful loan has a high probability of total or substantial loss, but because of specific pending events that may strengthen the asset, its classification as a loss is deferred. Doubtful borrowers are usually in default, lack adequate liquidity or capital and lack the resources necessary to remain an operating entity. Pending events can include mergers, acquisitions, liquidations, capital injections, the perfection of liens on additional collateral, the valuation of collateral and refinancing. Generally, pending events should be resolved within a relatively short period and the ratings will be adjusted based on the new information. Nonaccrual treatment is required for Doubtful assets because of the high probability of loss. Substandard Substandard loans have a high probability of payment default or they have other well-defined weaknesses. They require more intensive supervision by bank management. Substandard loans are generally characterized by current or expected unprofitable operations, inadequate debt service coverage, inadequate liquidity or marginal capitalization. Repayment may depend on collateral or other credit risk mitigants. For some Substandard loans, the likelihood of full collection of interest and principal may be in doubt and those loans should be placed on nonaccrual. Although Substandard assets in the aggregate will have a distinct potential for loss, an individual asset’s loss potential does not have to be distinct for the asset to be rated Substandard. Special Mention Special Mention loans have potential weaknesses that may, if not checked or corrected, weaken the asset or inadequately protect the Company’s position at some future date. These loans pose elevated risk, but their weakness does not yet justify a Substandard classification. Borrowers may be experiencing adverse operating trends (i.e., declining revenues or margins) or may be struggling with an ill-proportioned balance sheet (i.e., increasing inventory without an increase in sales, high leverage and/or tight liquidity). Adverse economic or market conditions, such as interest rate increases or the entry of a new competitor, may also support a Special Mention rating. Although a Special Mention loan has a higher probability of default than a Pass asset, its default is not imminent. Pass Loans graded as Pass encompass all loans not graded as Doubtful, Substandard or Special Mention. Pass loans are in compliance with loan covenants and payments are generally made as agreed. Pass loans range from superior quality to fair quality. Pass loans also include any portion of a government guaranteed loan, including Paycheck Protection Program loans. Consumer and Residential Grading System Consumer and Residential loans are graded as either Nonperforming or Performing. Nonperforming Nonperforming loans are loans that are (1) over 90 days past due and interest is still accruing or (2) on nonaccrual status. Performing All loans not meeting any of the above criteria are considered Performing.
Loan Modifications to Borrowers Experiencing Financial Difficulties	Loan Modifications to Borrowers Experiencing Financial Difficulties When the Company modifies a loan with financial difficulty, such modifications generally include one or a combination of the following: an extension of the maturity date at a stated rate of interest lower than the current market rate for new debt with similar risk; a change in scheduled payment amount; or principal forgiveness.

Defined Benefit Post-Retireme_2

Defined Benefit Post-Retirement Plans (Policies)	3 Months Ended
	Mar. 31, 2024
Defined Benefit Post-Retirement Plans [Abstract]
Postemployment Benefit Plans, Policy	The Company has a qualified, noncontributory, defined benefit pension plan (the “Plan”) covering substantially all of its employees at March 31, 2024. Benefits paid from the Plan are based on age, years of service, compensation and social security benefits and are determined in accordance with defined formulas. The Company’s policy is to fund the Plan in accordance with Employee Retirement Income Security Act of 1974 standards. Assets of the Plan are invested in publicly traded stocks, bonds and mutual funds. In addition to the Plan, the Company provides supplemental employee retirement plans to certain current and former executives. These supplemental employee retirement plans and the Plan are collectively referred to herein as “Pension Benefits.” In addition, the Company provides certain health care benefits for retired employees. Benefits were accrued over the employees’ active service period. Only employees that were employed by the Company on or before January 1, 2000 are eligible to receive post-retirement health care benefits. These post-retirement benefits are referred to herein as “Other Benefits.” Accounting standards require an employer to: (1) recognize the overfunded or underfunded status of defined benefit post-retirement plans, which is measured as the difference between plan assets at fair value and the benefit obligation, as an asset or liability in its balance sheet; (2) recognize changes in that funded status in the year in which the changes occur through comprehensive income; and (3) measure the defined benefit plan assets and obligations as of the date of its year-end balance sheet. The Company made no voluntary contributions to the Pension Benefits and Other Benefits plans during the three months ended March 31, 2024 and 2023.

Earnings Per Share (Policies)

Earnings Per Share (Policies)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	Basic EPS excludes dilution and is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity (such as the Company’s dilutive stock options and restricted stock units).

Fair Value Measurements and F_2

Fair Value Measurements and Fair Value of Financial Instruments (Policies)	3 Months Ended
	Mar. 31, 2024
Fair Value Measurements and Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments, Policy	G AAP states that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value measurements are not adjusted for transaction costs. A fair value hierarchy exists within GAAP that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below: Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 - Quoted prices for similar assets or liabilities in active markets, quoted prices in markets that are not active or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability; and Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The types of instruments valued based on quoted market prices in active markets include most U.S. government and agency securities, many other sovereign government obligations, liquid mortgage products, active listed equities and most money market securities. Such instruments are generally classified within Level 1 or Level 2 of the fair value hierarchy. The Company does not adjust the quoted prices for such instruments. The types of instruments valued based on quoted prices in markets that are not active, broker or dealer quotations or quote from alternative pricing sources with reasonable levels of price transparency include most investment-grade and high-yield corporate bonds, less liquid mortgage products, less liquid agency securities, less liquid listed equities, state, municipal and provincial obligations and certain physical commodities. Such instruments are generally classified within Level 2 of the fair value hierarchy. Certain common equity securities are reported at fair value utilizing Level 1 inputs (exchange quoted prices). Other investment securities are reported at fair value utilizing Level 1 and Level 2 inputs. The prices for Level 2 instruments are obtained through an independent pricing service or dealer market participants with whom the Company has historically transacted both purchases and sales of investment securities. Prices obtained from these sources include prices derived from market quotations and matrix pricing. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. Management reviews the methodologies used by its third-party providers in pricing the securities. Level 3 is for positions that are not traded in active markets or are subject to transfer restrictions. Valuations are adjusted to reflect illiquidity and/or non-transferability and such adjustments are generally based on available market evidence. In the absence of such evidence, management’s best estimate will be used. Management’s best estimate consists of both internal and external support on certain Level 3 investments. Subsequent to inception, management only changes Level 3 inputs and assumptions when corroborated by evidence such as transactions in similar instruments, completed or pending third-party transactions in the underlying investment or comparable entities, subsequent rounds of financing, recapitalizations and other transactions across the capital structure, offerings in the equity or debt markets and changes in financial ratios or cash flow GAAP requires disclosure of assets and liabilities measured and recorded at fair value on a non-recurring basis such as goodwill, loans held for sale, other real estate owned, collateral-dependent loans individually evaluated for expected credit losses and HTM securities. There were no loans individually evaluated for expected credit losses where the amortized cost was adjusted to fair value as of March 31, 2024 and December 31, 2023, respectively. The Company uses the fair value of underlying collateral, less costs to sell, to estimate the allowance for credit losses for individually evaluated collateral dependent loans. The appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses ranging from 10% to 50% Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument. Because no market exists for a significant portion of the Company’s financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates. Fair value estimates are based on existing on and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. For example, the Company has a substantial wealth operation that contributes net fee income annually. The wealth management operation is not considered a financial instrument and its value has not been incorporated into the fair value estimates. Other significant assets and liabilities include the benefits resulting from the low-cost funding of deposit liabilities as compared to the cost of borrowing funds in the market and premises and equipment. In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in the estimate of fair value. HTM Securities The fair value of the Company’s HTM securities is primarily measured using information from a third-party pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. Net Loans Net loans include portfolio loans and loans held for sale. Loans were first segregated by type and then further segmented into fixed and variable rate and loan quality categories. Expected future cash flows were projected based on contractual cash flows, adjusted for estimated prepayments, and those expected future cash flows also includes credit risk, illiquidity risk and other market factors to calculate the exit price fair value in accordance with ASC 820. Time Deposits The fair value of time deposits was estimated using a discounted cash flow approach that applies prevailing market interest rates for similar maturity instruments. The fair values of the Company’s time deposit liabilities do not take into consideration the value of the Company’s long-term relationships with depositors, which may have significant value. Long-Term Debt The fair value of long-term debt was estimated using a discounted cash flow approach that applies prevailing market interest rates for similar maturity instruments. Subordinated Debt The fair value of subordinated debt has been measured using the observable market price as of the period reported. Junior Subordinated Debt The fair value of junior subordinated debt has been estimated using a discounted cash flow analysis.

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2024
Securities [Abstract]
Amortized Cost, Estimated Fair Value and Unrealized Gains (Losses) of AFS Securities	The amortized cost, estimated fair value and unrealized gains (losses) of AFS securities are as follows: (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value As of March 31, 2024 U.S. treasury $ 133,442 $ - $ (8,759 ) $ 124,683 Federal agency 248,375 - (35,071 ) 213,304 State & municipal 96,054 1 (10,022 ) 86,033 Mortgage-backed: Government-sponsored enterprises 387,479 3 (45,461 ) 342,021 U.S. government agency securities 71,036 10 (7,520 ) 63,526 Collateralized mortgage obligations: Government-sponsored enterprises 452,853 49 (50,135 ) 402,767 U.S. government agency securities 170,293 - (26,034 ) 144,259 Corporate 48,451 - (6,573 ) 41,878 Total AFS securities $ 1,607,983 $ 63 $ (189,575 ) $ 1,418,471 As of December 31, 2023 U.S. treasury $ 133,302 $ - $ (8,278 ) $ 125,024 Federal agency 248,384 - (33,644 ) 214,740 State & municipal 96,251 11 (9,956 ) 86,306 Mortgage-backed: Government-sponsored enterprises 399,532 7 (44,264 ) 355,275 U.S. government agency securities 74,281 14 (7,302 ) 66,993 Collateralized mortgage obligations: Government-sponsored enterprises 452,715 15 (48,257 ) 404,473 U.S. government agency securities 162,171 - (25,100 ) 137,071 Corporate 48,442 - (7,466 ) 40,976 Total AFS securities $ 1,615,078 $ 47 $ (184,267 ) $ 1,430,858
Amortized Cost, Estimated Fair Value and Unrealized Gains (Losses) of HTM Securities	The amortized cost, estimated fair value and unrealized gains (losses) of HTM securities are as follows: (In thousands) Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value As of March 31, 2024 Federal agency $ 100,000 $ - $ (18,440 ) $ 81,560 Mortgage-backed: Government-sponsored enterprises 224,344 - (34,187 ) 190,157 U.S. government agency securities 16,742 2 (736 ) 16,008 Collateralized mortgage obligations: Government-sponsored enterprises 182,813 - (13,466 ) 169,347 U.S. government agency securities 63,137 - (11,206 ) 51,931 State & municipal 303,827 99 (19,610 ) 284,316 Total HTM securities $ 890,863 $ 101 $ (97,645 ) $ 793,319 As of December 31, 2023 Federal agency $ 100,000 $ - $ (17,784 ) $ 82,216 Mortgage-backed: Government-sponsored enterprises 228,720 - (31,613 ) 197,107 U.S. government agency securities 17,086 3 (566 ) 16,523 Collateralized mortgage obligations: Government-sponsored enterprises 187,457 57 (12,021 ) 175,493 U.S. government agency securities 63,878 - (10,908 ) 52,970 State & municipal 308,126 211 (18,122 ) 290,215 Total HTM securities $ 905,267 $ 271 $ (91,014 ) $ 814,524
Gains and (Losses) on Equity Securities	The following table sets forth information with regard to gains and (losses) on equity securities: Three Months Ended March 31, (In thousands) 2024 2023 Net (losses) and gains recognized on equity securities $ (101 ) $ 2 Less: Net (losses) and gains recognized on equity securities sold during the period - - Unrealized (losses) and gains recognized on equity securities still held $ (101 ) $ 2
Contractual Maturities of Debt Securities	The following table sets forth information with regard to contractual maturities of debt securities at March 31, 2024: (In thousands) Amortized Cost Estimated Fair Value AFS debt securities: Within one year $ 50,294 $ 49,553 From one to five years 567,513 508,211 From five to ten years 314,839 277,648 After ten years 675,337 583,059 Total AFS debt securities $ 1,607,983 $ 1,418,471 HTM debt securities: Within one year $ 98,660 $ 98,460 From one to five years 125,141 119,411 From five to ten years 242,973 210,783 After ten years 424,089 364,665 Total HTM debt securities $ 890,863 $ 793,319
Investment Securities with Unrealized Losses	The following table sets forth information with regard to investment securities with unrealized losses, for which an allowance for credit losses has not been recorded, segregated according to the length of time the securities had been in a continuous unrealized loss position: Less Than 12 Months 12 Months or Longer Total (In thousands) Fair Value Unrealized Losses Number of Positions Fair Value Unrealized Losses Number of Positions Fair Value Unrealized Losses Number of Positions As of March 31, 2024 AFS securities: U.S. treasury $ - $ - - $ 124,683 $ (8,759 ) 8 $ 124,683 $ (8,759 ) 8 Federal agency - - - 213,304 (35,071 ) 16 213,304 (35,071 ) 16 State & municipal - - - 85,266 (10,022 ) 66 85,266 (10,022 ) 66 Mortgage-backed 136 (1 ) 9 404,618 (52,980 ) 158 404,754 (52,981 ) 167 Collateralized mortgage obligations 11,033 (59 ) 2 523,989 (76,110 ) 120 535,022 (76,169 ) 122 Corporate 1,459 (2 ) 1 40,419 (6,571 ) 14 41,878 (6,573 ) 15 Total securities with unrealized losses $ 12,628 $ (62 ) 12 $ 1,392,279 $ (189,513 ) 382 $ 1,404,907 $ (189,575 ) 394 HTM securities: Federal agency $ - $ - - $ 81,560 $ (18,440 ) 4 $ 81,560 $ (18,440 ) 4 Mortgage-backed 11,905 (489 ) 1 194,181 (34,434 ) 33 206,086 (34,923 ) 34 Collateralized mortgage obligation 8,189 (58 ) 1 213,088 (24,614 ) 52 221,277 (24,672 ) 53 State & municipal 4,423 (13 ) 4 181,355 (19,597 ) 205 185,778 (19,610 ) 209 Total securities with unrealized losses $ 24,517 $ (560 ) 6 $ 670,184 $ (97,085 ) 294 $ 694,701 $ (97,645 ) 300 As of December 31, 2023 AFS securities: U.S. treasury $ - $ - - $ 125,024 $ (8,278 ) 8 $ 125,024 $ (8,278 ) 8 Federal agency - - - 214,740 (33,644 ) 16 214,740 (33,644 ) 16 State & municipal - - - 85,528 (9,956 ) 66 85,528 (9,956 ) 66 Mortgage-backed 53 (1 ) 7 421,259 (51,565 ) 156 421,312 (51,566 ) 163 Collateralized mortgage obligations 1,333 (6 ) 2 536,678 (73,351 ) 118 538,011 (73,357 ) 120 Corporate 1,379 (75 ) 1 39,597 (7,391 ) 14 40,976 (7,466 ) 15 Total securities with unrealized losses $ 2,765 $ (82 ) 10 $ 1,422,826 $ (184,185 ) 378 $ 1,425,591 $ (184,267 ) 388 HTM securities: Federal agency $ - $ - - $ 82,216 $ (17,784 ) 4 $ 82,216 $ (17,784 ) 4 Mortgage-backed 12,221 (365 ) 1 201,320 (31,814 ) 33 213,541 (32,179 ) 34 Collateralized mortgage obligations - - - 219,820 (22,929 ) 54 219,820 (22,929 ) 54 State & municipal 14,422 (127 ) 21 171,904 (17,995 ) 189 186,326 (18,122 ) 210 Total securities with unrealized losses $ 26,643 $ (492 ) 22 $ 675,260 $ (90,522 ) 280 $ 701,903 $ (91,014 ) 302

Loans (Tables)

Loans (Tables)	3 Months Ended
	Mar. 31, 2024
Loans [Abstract]
Loans, Net of Deferred Fees and Origination Costs	A summary of loans, net of deferred fees and origination costs, by category is as follows: (In thousands) March 31, 2024 December 31, 2023 Commercial & industrial $ 1,353,446 $ 1,354,248 Commercial real estate 3,646,739 3,626,910 Residential real estate 2,133,289 2,125,804 Home equity 328,673 337,214 Indirect auto 1,190,734 1,130,132 Residential solar 896,147 917,755 Other consumer 139,049 158,650 Total loans $ 9,688,077 $ 9,650,713

Allowance for Credit Losses a_3

Allowance for Credit Losses and Credit Quality of Loans (Tables)	3 Months Ended
	Mar. 31, 2024
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Allowance for Loan Losses by Portfolio	The following tables present the activity in the allowance for credit losses by our portfolio segments: (In thousands) Commercial Loans Consumer Loans Residential Total Balance as of December 31, 2023 $ 45,903 $ 46,427 $ 22,070 $ 114,400 Charge-offs (985 ) (5,581 ) (114 ) (6,680 ) Recoveries 198 1,651 152 2,001 Provision (644 ) 4,922 1,301 5,579 Ending balance as of March 31 2024 $ 44,472 $ 47,419 $ 23,409 $ 115,300 Balance as of January 1, 2023 (after adoption of ASC 2022-02) $ 34,662 $ 50,951 $ 14,539 $ 100,152 Charge-offs (169 ) (5,342 ) (339 ) (5,850 ) Recoveries 541 1,377 121 2,039 Provision 1,006 1,834 1,069 3,909 Ending balance as of March 31 2023 $ 36,040 $ 48,820 $ 15,390 $ 100,250
Past due and Nonperforming Loans by Loan Class	The following table sets forth information with regard to past due and nonperforming loans by loan segment: (In thousands) 31-60 Days Past Due Accruing 61-90 Days Past Due Accruing Greater Than 90 Days Past Due Accruing Total Past Due Accruing Nonaccrual Current Recorded Total Loans As of March 31 2024 Commercial loans: C&I $ 1,711 $ 750 $ - $ 2,461 $ 3,079 $ 1,398,831 $ 1,404,371 CRE 1,929 64 - 1,993 18,743 3,424,810 3,445,546 Total commercial loans $ 3,640 $ 814 $ - $ 4,454 $ 21,822 $ 4,823,641 $ 4,849,917 Consumer loans: Auto $ 10,376 $ 1,676 $ 1,045 $ 13,097 $ 2,274 $ 1,142,702 $ 1,158,073 Residential solar 3,940 1,362 446 5,748 125 890,274 896,147 Other consumer 2,054 1,158 882 4,094 299 146,372 150,765 Total consumer loans $ 16,370 $ 4,196 $ 2,373 $ 22,939 $ 2,698 $ 2,179,348 $ 2,204,985 Residential $ 3,799 $ 858 $ 227 $ 4,884 $ 10,669 $ 2,617,622 $ 2,633,175 Total loans $ 23,809 $ 5,868 $ 2,600 $ 32,277 $ 35,189 $ 9,620,611 $ 9,688,077 (In thousands) 31-60 Days Past Due Accruing 61-90 Days Past Due Accruing Greater Than 90 Days Past Due Accruing Total Past Due Accruing Nonaccrual Current Recorded Total Loans As of December 31 2023 Commercial loans: C&I $ 414 $ 33 $ 1 $ 448 $ 3,441 $ 1,393,616 $ 1,397,505 CRE 803 835 - 1,638 18,126 3,413,984 3,433,748 Total commercial loans $ 1,217 $ 868 $ 1 $ 2,086 $ 21,567 $ 4,807,600 $ 4,831,253 Consumer loans: Auto $ 10,115 $ 2,011 $ 1,067 $ 13,193 $ 2,106 $ 1,084,143 $ 1,099,442 Residential solar 3,074 1,301 915 5,290 245 912,220 917,755 Other consumer 2,343 1,811 1,124 5,278 215 164,867 170,360 Total consumer loans $ 15,532 $ 5,123 $ 3,106 $ 23,761 $ 2,566 $ 2,161,230 $ 2,187,557 Residential $ 3,836 $ 399 $ 554 $ 4,789 $ 10,080 $ 2,617,034 $ 2,631,903 Total loans $ 20,585 $ 6,390 $ 3,661 $ 30,636 $ 34,213 $ 9,585,864 $ 9,650,713
Credit Quality by Loan Class by Year of Origination (Vintage)	The following tables illustrate the Company’s credit quality by loan class by vintage and includes gross charge-offs by loan class by vintage. Included in other consumer gross charge-offs for the three months ended March 31, 2024, the Company recorded $0.2 million in overdrawn deposit accounts reported as 2023 originations. Included in other consumer gross charge-offs for the year ended December 31, 2023, the Company recorded $0.2 million in overdrawn deposit accounts reported as 2022 originations and $0.8 million in overdrawn deposit accounts reported as 2023 originations. (In thousands) 2024 2023 2022 2021 2020 Prior Revolving Loans Amortized Cost Basis Revolving Loans Converted to Term Total As of March 31 2024 C&I By internally assigned grade: Pass $ 60,820 $ 214,985 $ 243,619 $ 231,577 $ 146,409 $ 129,310 $ 318,078 $ 2,585 $ 1,347,383 Special mention - 1,795 2,802 378 3,845 1,812 15,946 251 26,829 Substandard - 2,934 3,154 1,885 289 6,845 14,880 127 30,114 Doubtful - 21 1 19 - 4 - - 45 Total C&I $ 60,820 $ 219,735 $ 249,576 $ 233,859 $ 150,543 $ 137,971 $ 348,904 $ 2,963 $ 1,404,371 Current-period gross charge-offs $ - $ (9 ) $ (900 ) $ - $ - $ (76 ) $ - $ - $ (985 ) CRE By internally assigned grade: Pass $ 81,048 $ 362,660 $ 492,661 $ 546,787 $ 449,533 $ 1,013,118 $ 308,977 $ 37,243 $ 3,292,027 Special mention - 3,602 5,971 7,842 3,875 28,841 3,547 - 53,678 Substandard - - 726 17,961 1,132 61,499 1,542 16,981 99,841 Total CRE $ 81,048 $ 366,262 $ 499,358 $ 572,590 $ 454,540 $ 1,103,458 $ 314,066 $ 54,224 $ 3,445,546 Current-period gross charge-offs $ - $ - $ - $ - $ - $ - $ - $ - $ - Auto By payment activity: Performing $ 175,451 $ 430,001 $ 331,202 $ 138,915 $ 36,140 $ 43,045 $ - $ - $ 1,154,754 Nonperforming 29 1,014 1,171 724 94 287 - - 3,319 Total auto $ 175,480 $ 431,015 $ 332,373 $ 139,639 $ 36,234 $ 43,332 $ - $ - $ 1,158,073 Current-period gross charge-offs $ - $ (274 ) $ (493 ) $ (226 ) $ (12 ) $ (122 ) $ - $ - $ (1,127 ) Residential solar By payment activity: Performing $ 1,365 $ 149,789 $ 422,422 $ 176,158 $ 63,222 $ 82,620 $ - $ - $ 895,576 Nonperforming - - 432 76 - 63 - - 571 Total residential solar $ 1,365 $ 149,789 $ 422,854 $ 176,234 $ 63,222 $ 82,683 $ - $ - $ 896,147 Current-period gross charge-offs $ - $ (53 ) $ (910 ) $ (136 ) $ - $ (196 ) $ - $ - $ (1,295 ) Other consumer By payment activity: Performing $ 5,600 $ 10,559 $ 22,720 $ 47,947 $ 18,029 $ 25,681 $ 19,015 $ 33 $ 149,584 Nonperforming - 5 184 650 39 295 1 7 1,181 Total other consumer $ 5,600 $ 10,564 $ 22,904 $ 48,597 $ 18,068 $ 25,976 $ 19,016 $ 40 $ 150,765 Current-period gross charge-offs $ - $ (250 ) $ (811 ) $ (1,453 ) $ (364 ) $ (281 ) $ - $ - $ (3,159 ) Residential By payment activity: Performing $ 39,693 $ 258,154 $ 336,357 $ 438,007 $ 273,451 $ 1,006,816 $ 255,582 $ 14,219 $ 2,622,279 Nonperforming - 626 825 1,605 272 7,568 - - 10,896 Total residential $ 39,693 $ 258,780 $ 337,182 $ 439,612 $ 273,723 $ 1,014,384 $ 255,582 $ 14,219 $ 2,633,175 Current-period gross charge-offs $ - $ - $ - $ - $ - $ (114 ) $ - $ - $ (114 ) Total loans $ 364,006 $ 1,436,145 $ 1,864,247 $ 1,610,531 $ 996,330 $ 2,407,804 $ 937,568 $ 71,446 $ 9,688,077 Current-period gross charge-offs $ - $ (586 ) $ (3,114 ) $ (1,815 ) $ (376 ) $ (789 ) $ - $ - $ (6,680 ) (In thousands) 2023 2022 2021 2020 2019 Prior Revolving Loans Amortized Cost Basis Revolving Loans Converted to Term Total As of December 31, 2023 C&I By internally assigned grade: Pass $ 229,249 $ 270,796 $ 241,993 $ 158,051 $ 74,469 $ 63,826 $ 299,248 $ 2,923 $ 1,340,555 Special mention 420 1,672 277 3,524 87 1,854 19,489 - 27,323 Substandard 1,496 2,461 1,609 282 2,266 5,632 14,266 1,607 29,619 Doubtful - 1 2 - 4 1 - - 8 Total C&I $ 231,165 $ 274,930 $ 243,881 $ 161,857 $ 76,826 $ 71,313 $ 333,003 $ 4,530 $ 1,397,505 Current-period gross charge-offs $ (24 ) $ (3,021 ) $ (5 ) $ (86 ) $ - $ (600 ) $ - $ - $ (3,736 ) CRE By internally assigned grade: Pass $ 353,161 $ 518,201 $ 561,897 $ 452,110 $ 327,804 $ 739,189 $ 294,039 $ 33,705 $ 3,280,106 Special mention 3,577 4,472 10,711 7,055 9,967 39,460 2,970 - 78,212 Substandard 370 731 21,807 1,146 2,996 37,418 10,962 - 75,430 Total CRE $ 357,108 $ 523,404 $ 594,415 $ 460,311 $ 340,767 $ 816,067 $ 307,971 $ 33,705 $ 3,433,748 Current-period gross charge-offs $ - $ - $ - $ - $ (114 ) $ (304 ) $ - $ - $ (418 ) Auto By payment activity: Performing $ 474,369 $ 363,516 $ 157,251 $ 42,644 $ 45,406 $ 13,071 $ 12 $ - $ 1,096,269 Nonperforming 532 1,241 830 190 306 74 - - 3,173 Total auto $ 474,901 $ 364,757 $ 158,081 $ 42,834 $ 45,712 $ 13,145 $ 12 $ - $ 1,099,442 Current-period gross charge-offs $ (102 ) $ (1,183 ) $ (1,066 ) $ (340 ) $ (301 ) $ (295 ) $ - $ - $ (3,287 ) Residential solar By payment activity: Performing $ 155,425 $ 430,855 $ 178,839 $ 65,382 $ 46,554 $ 39,540 $ - $ - $ 916,595 Nonperforming - 837 205 18 47 53 - - 1,160 Total residential solar $ 155,425 $ 431,692 $ 179,044 $ 65,400 $ 46,601 $ 39,593 $ - $ - $ 917,755 Current-period gross charge-offs $ (150 ) $ (1,930 ) $ (923 ) $ (45 ) $ (558 ) $ (345 ) $ - $ - $ (3,951 ) Other consumer By payment activity: Performing $ 13,089 $ 27,394 $ 57,876 $ 21,087 $ 14,548 $ 15,964 $ 19,042 $ 21 $ 169,021 Nonperforming - 244 685 144 56 161 4 45 1,339 Total other consumer $ 13,089 $ 27,638 $ 58,561 $ 21,231 $ 14,604 $ 16,125 $ 19,046 $ 66 $ 170,360 Current-period gross charge-offs $ (885 ) $ (3,744 ) $ (7,511 ) $ (1,329 ) $ (832 ) $ (568 ) $ - $ - $ (14,869 ) Residential By payment activity: Performing $ 212,799 $ 366,860 $ 453,206 $ 267,845 $ 167,860 $ 876,563 $ 260,836 $ 15,300 $ 2,621,269 Nonperforming 134 430 1,121 385 591 7,460 - 513 10,634 Total residential $ 212,933 $ 367,290 $ 454,327 $ 268,230 $ 168,451 $ 884,023 $ 260,836 $ 15,813 $ 2,631,903 Current-period gross charge-offs $ - $ - $ (81 ) $ (30 ) $ - $ (406 ) $ - $ - $ (517 ) Total loans $ 1,444,621 $ 1,989,711 $ 1,688,309 $ 1,019,863 $ 692,961 $ 1,840,266 $ 920,868 $ 54,114 $ 9,650,713 Current-period gross charge-offs $ (1,161 ) $ (9,878 ) $ (9,586 ) $ (1,830 ) $ (1,805 ) $ (2,518 ) $ - $ - $ (26,778 )
Amortized Cost Basis of Loans Modified to Borrowers Experiencing Financial Difficulty	The following table shows the amortized cost basis at the end of the reporting period of the loans modified to borrowers experiencing financial difficulty, disaggregated by class of financing receivable and type of concession granted: Three Months Ended March 31, 2024 Term Extension (Dollars in thousands) Amortized Cost % of Total Class of Financing Receivables Residential $ 294 0.011 % Total $ 294 Three Months Ended March 31, 2023 Term Extension (Dollars in thousands) Amortized Cost % of Total Class of Financing Receivables Residential $ 43 0.002 % Total $ 43
Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty	The following table describes the financial effect of the modifications made to borrowers experiencing financial difficulties: Three Months Ended March 31, 2024 Loan Type Term Extension Residential Added a weighted-average 7.4 years to the life of loans, which reduced monthly payment amounts for the borrowers. Three Months Ended March 31, 2023 Loan Type Term Extension Residential Added a weighted-average 18 years to the life of loans, which reduced monthly payment amounts for the borrowers.
Performance of Modified Loans	The Payment Status (Amortized Cost Basis) (In thousands) Current 31-60 Days Past Due 61-90 Days Past Due Greater than 90 Days Past Due As of March 31, 2024 Loan Type Residential $ 863 $ - $ - $ 29 Total $ 863 $ - $ - $ 29

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	3 Months Ended
	Mar. 31, 2024
Short-Term Borrowings [Abstract]
Information Related to Short-term Borrowings	Information related to short-term borrowings is summarized as follows: (In thousands) March 31, 2024 December 31, 2023 Federal funds purchased $ 78,000 $ - Securities sold under repurchase agreements 86,134 93,651 Other short-term borrowings 103,000 293,000 Total short-term borrowings $ 267,134 $ 386,651

Defined Benefit Post-Retireme_3

Defined Benefit Post-Retirement Plans (Tables)	3 Months Ended
	Mar. 31, 2024
Defined Benefit Post-Retirement Plans [Abstract]
Net Periodic Pension Benefits and Other Benefit Costs	The components of expense for Pension Benefits and Other Benefits are set forth below: Pension Benefits Other Benefits Three Months Ended March 31, Three Months Ended March 31, (In thousands) 2024 2023 2024 2023 Components of net periodic (benefit) cost: Service cost $ 514 $ 482 $ 1 $ 1 Interest cost 1,005 1,010 55 56 Expected return on plan assets (1,983 ) (1,853 ) - - Net amortization 453 670 (1 ) (21 ) Total net periodic (benefit) cost $ (11 ) $ 309 $ 55 $ 36

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Reconciliation of Basic and Diluted Earnings Per Share	The following is a reconciliation of basic and diluted EPS for the periods presented in the unaudited interim consolidated statements of income: Three Months Ended March 31, (In thousands, except per share data) 2024 2023 Basic EPS: Weighted average common shares outstanding 47,148 42,894 Net income available to common stockholders $ 33,823 $ 33,658 Basic EPS $ 0.72 $ 0.78 Diluted EPS: Weighted average common shares outstanding 47,148 42,894 Dilutive effect of common stock options and restricted stock 222 232 Weighted average common shares and common share equivalents 47,370 43,126 Net income available to common stockholders $ 33,823 $ 33,658 Diluted EPS $ 0.71 $ 0.78

Reclassification Adjustments _2

Reclassification Adjustments Out of Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2024
Reclassification Adjustments Out of Other Comprehensive Income (Loss) [Abstract]
Reclassification Adjustments out of AOCI	The following table summarizes the reclassification adjustments out of AOCI: Detail About AOCI Components Amount Reclassified from AOCI Affected Line Item in the Consolidated Statements of Comprehensive Income (Loss) Three Months Ended (In thousands) March 31, 2024 March 31, 2023 AFS securities: Losses on AFS securities $ - $ 5,000 Net securities (gains) losses Amortization of unrealized gains related to securities transfer 96 114 Interest income Tax effect $ (24 ) $ (1,278 ) Income tax (benefit) Net of tax $ 72 $ 3,836 Pension and other benefits: Amortization of net losses $ 454 $ 640 Other noninterest expense Amortization of prior service costs (2 ) 9 Other noninterest expense Tax effect $ (113 ) $ (163 ) Income tax (benefit) Net of tax $ 339 $ 486 Total reclassifications, net of tax $ 411 $ 4,322

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Summary of Derivatives Outstanding	The following table summarizes the derivatives outstanding: (In thousands) Notional Amount Balance Sheet Location Fair Value Notional Amount Balance Sheet Location Fair Value As of March 31 2024 Derivatives not designated as hedging instruments Interest rate derivatives $ 1,330,997 Other assets $ 114,205 $ 1,330,997 Other liabilities $ 114,101 Risk participation agreements 71,511 Other assets 84 15,571 Other liabilities 3 Total derivatives not designated as hedging instruments $ 114,289 $ 114,104 Netting adjustments (1) 24,321 - Net derivatives in the balance sheet $ 89,968 $ 114,104 Derivatives not offset on the balance sheet $ 1,924 $ 1,924 Cash collateral (2) - - Net derivative amounts $ 88,044 $ 112,180 As of December 31, 2023 Derivatives not designated as hedging instruments Interest rate derivatives $ 1,303,711 Other assets $ 95,972 $ 1,303,711 Other liabilities $ 95,869 Risk participation agreements 62,112 Other assets 19 16,146 Other liabilities 6 Total derivatives not designated as hedging instruments $ 95,991 $ 95,875 Netting adjustments (1) 20,849 - Net derivatives in the balance sheet $ 75,142 $ 95,875 Derivatives not offset on the balance sheet $ 2,930 $ 2,930 Cash collateral (2) - - Net derivative amounts $ 72,212 $ 92,945 (1) Netting adjustments represents the amounts recorded to convert derivatives assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance on the settle to market rules for cleared derivatives. The CME legally characterizes the variation margin posted between counterparties as settlements of the outstanding derivative contracts instead of cash collateral. (2) Cash collateral represents the amount that cannot be used to offset our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The other collateral consists of securities and is exchanged under bilateral collateral and master netting agreements that allow us to offset the net derivative position with the related collateral. The application of the other collateral cannot reduce the net derivative position below zero. Therefore, excess other collateral, if any, is not reflected above.
Not Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Effect of Derivatives on AOCI and on Consolidated Statement of Income	The following table indicates the gain or loss recognized in income on derivatives not designated as a hedging relationship: Three Months Ended March 31, (In thousands) 2024 2023 Derivatives not designated as hedging instruments: Increase in other income $ 75 $ 7

Fair Value Measurements and F_3

Fair Value Measurements and Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Measurements and Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis	The following tables set forth the Company’s financial assets and liabilities measured on a recurring basis that were accounted for at fair value. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement: (In thousands) Level 1 Level 2 Level 3 March 31, 2024 Assets: AFS securities: U.S. treasury $ 124,683 $ - $ - $ 124,683 Federal agency - 213,304 - 213,304 State & municipal - 86,033 - 86,033 Mortgage-backed - 405,547 - 405,547 Collateralized mortgage obligations - 547,026 - 547,026 Corporate - 41,878 - 41,878 Total AFS securities $ 124,683 $ 1,293,788 $ - $ 1,418,471 Equity securities 38,470 1,000 - 39,470 Derivatives - 89,968 - 89,968 Total $ 163,153 $ 1,384,756 $ - $ 1,547,909 Liabilities: Derivatives $ - $ 114,104 $ - $ 114,104 Total $ - $ 114,104 $ - $ 114,104 (In thousands) Level 1 Level 2 Level 3 December 31, 2023 Assets: AFS securities: U.S. treasury $ 125,024 $ - $ - $ 125,024 Federal agency - 214,740 - 214,740 State & municipal - 86,306 - 86,306 Mortgage-backed - 422,268 - 422,268 Collateralized mortgage obligations - 541,544 - 541,544 Corporate - 40,976 - 40,976 Total AFS securities $ 125,024 $ 1,305,834 $ - $ 1,430,858 Equity securities 36,591 1,000 - 37,591 Derivatives - 75,142 - 75,142 Total $ 161,615 $ 1,381,976 $ - $ 1,543,591 Liabilities: Derivatives $ - $ 95,875 $ - $ 95,875 Total $ - $ 95,875 $ - $ 95,875
Information with Regard to Estimated Fair Values of Financial Instruments	The following table sets forth information with regard to estimated fair values of financial instruments. This table excludes financial instruments for which the carrying amount approximates fair value. Financial instruments for which the fair value approximates carrying value include cash and cash equivalents, AFS securities, equity securities, accrued interest receivable, non-maturity deposits, short-term borrowings, accrued interest payable and derivatives. March 31, 2024 December 31, 2023 (In thousands) Fair Value Hierarchy Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets: HTM securities 2 $ 890,863 $ 793,319 $ 905,267 $ 814,524 Net loans 3 9,576,040 9,173,300 9,539,684 9,216,162 Financial liabilities: Time deposits 2 $ 1,368,136 $ 1,348,934 $ 1,324,709 $ 1,285,999 Long-term debt 2 29,759 29,315 29,796 29,416 Subordinated debt 1 120,628 116,563 120,380 113,757 Junior subordinated debt 2 101,196 103,202 101,196 102,337

Securities, Available for Sale

Securities, Available for Sale (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt securities, available-for-sale [Abstract]
Amortized cost	$ 1,607,983		$ 1,615,078
Unrealized gains	63		47
Unrealized losses	(189,575)		(184,267)
Estimated fair value	1,418,471		1,430,858
Allowance for credit losses on AFS securities	0		0
Gross realized gains	0
Gross realized losses	0	$ 5,000
Gain recognized on sale of previously written-off security	2,300
U.S. Treasury [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	133,442		133,302
Unrealized gains	0		0
Unrealized losses	(8,759)		(8,278)
Estimated fair value	124,683		125,024
Federal Agency [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	248,375		248,384
Unrealized gains	0		0
Unrealized losses	(35,071)		(33,644)
Estimated fair value	213,304		214,740
State & Municipal [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	96,054		96,251
Unrealized gains	1		11
Unrealized losses	(10,022)		(9,956)
Estimated fair value	86,033		86,306
Mortgage-Backed, Government Sponsored Enterprises [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	387,479		399,532
Unrealized gains	3		7
Unrealized losses	(45,461)		(44,264)
Estimated fair value	342,021		355,275
Mortgage-Backed, U.S. Government Agency Securities [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	71,036		74,281
Unrealized gains	10		14
Unrealized losses	(7,520)		(7,302)
Estimated fair value	63,526		66,993
Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	452,853		452,715
Unrealized gains	49		15
Unrealized losses	(50,135)		(48,257)
Estimated fair value	402,767		404,473
Collateralized Mortgage Obligations, U.S. Government Agency Securities [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	170,293		162,171
Unrealized gains	0		0
Unrealized losses	(26,034)		(25,100)
Estimated fair value	144,259		137,071
Corporate [Member]
Debt securities, available-for-sale [Abstract]
Amortized cost	48,451		48,442
Unrealized gains	0		0
Unrealized losses	(6,573)		(7,466)
Estimated fair value	$ 41,878		$ 40,976
Loss on the write-off of an AFS debt security		$ 5,000

Securities, Held to Maturity (D

Securities, Held to Maturity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	$ 890,863		$ 905,267
Unrealized gains	101		271
Unrealized losses	(97,645)		(91,014)
Estimated fair value	793,319		814,524
Transactions of HTM securities [Abstract]
Gains from calls on HTM securities	0	$ 0
Asset Pledged as Collateral [Member] | Public Deposits or Other Purposes [Member]
Securities pledged [Abstract]
AFS and HTM securities	1,990,000		2,030,000
Asset Pledged as Collateral [Member] | Securities Sold under Repurchase Agreements [Member]
Securities pledged [Abstract]
AFS and HTM securities	159,300		177,200
Federal Agency [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	100,000		100,000
Unrealized gains	0		0
Unrealized losses	(18,440)		(17,784)
Estimated fair value	81,560		82,216
Mortgage-Backed, Government Sponsored Enterprises [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	224,344		228,720
Unrealized gains	0		0
Unrealized losses	(34,187)		(31,613)
Estimated fair value	190,157		197,107
Mortgage-Backed, U.S. Government Agency Securities [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	16,742		17,086
Unrealized gains	2		3
Unrealized losses	(736)		(566)
Estimated fair value	16,008		16,523
Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	182,813		187,457
Unrealized gains	0		57
Unrealized losses	(13,466)		(12,021)
Estimated fair value	169,347		175,493
Collateralized Mortgage Obligations, U.S. Government Agency Securities [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	63,137		63,878
Unrealized gains	0		0
Unrealized losses	(11,206)		(10,908)
Estimated fair value	51,931		52,970
State & Municipal [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	303,827		308,126
Unrealized gains	99		211
Unrealized losses	(19,610)		(18,122)
Estimated fair value	$ 284,316		$ 290,215

Securities, Gains and (Losses)

Securities, Gains and (Losses) on Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Gains (losses) on equity securities [Abstract]
Net (losses) and gains recognized on equity securities	$ (101)	$ 2
Less: Net (losses) and gains recognized on equity securities sold during the period	0	0
Unrealized (losses) and gains recognized on equity securities still held	(101)	2
Equity Securities without Readily Determinable Fair Value, Annual Amount [Abstract]
Carrying amount of equity securities without readily determinable fair values	1,000		$ 1,000
Impairment adjustments of equity securities without readily determinable fair values	0	0
Downward adjustments of equity securities without readily determinable fair values	0	0
Upward adjustments of equity securities without readily determinable fair values	$ 0	$ 0

Securities, AFS Debt Securities

Securities, AFS Debt Securities, Contractual Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Available-for-sale Securities, Debt Maturities, Amortized Cost [Abstract]
Within one year	$ 50,294
From one to five years	567,513
From five to ten years	314,839
After ten years	675,337
Amortized cost	1,607,983	$ 1,615,078
Available-for-sale Securities, Debt Maturities, Estimated Fair Value [Abstract]
Within one year	49,553
From one to five years	508,211
From five to ten years	277,648
After ten years	583,059
Fair value	$ 1,418,471	$ 1,430,858

Securities, HTM Debt Securities

Securities, HTM Debt Securities, Contractual Maturities (Details) $ in Thousands	Mar. 31, 2024 USD ($) Issuer	Dec. 31, 2023 USD ($) Issuer
Held-to-maturity Securities, Debt Maturities, Amortized Cost [Abstract]
Within one year	$ 98,660
From one to five years	125,141
From five to ten years	242,973
After ten years	424,089
Amortized cost	890,863	$ 905,267
Held-to-maturity Securities, Debt Maturities, Estimated Fair Value [Abstract]
Within one year	98,460
From one to five years	119,411
From five to ten years	210,783
After ten years	364,665
Fair value	$ 793,319	$ 814,524
Number of issuers whose holdings exceeded 10% of consolidated stockholders' equity, excluding U.S. Government securities and Government-sponsored enterprises securities | Issuer	0	0

Securities, AFS Securities in C

Securities, AFS Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	Mar. 31, 2024 USD ($) Position	Dec. 31, 2023 USD ($) Position
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 12,628	$ 2,765
12 months or longer	1,392,279	1,422,826
Total	1,404,907	1,425,591
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(62)	(82)
12 months or longer	(189,513)	(184,185)
Total	$ (189,575)	$ (184,267)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	12	10
12 months or longer | Position	382	378
Total | Position	394	388
AIR on AFS debt securities	$ 3,900	$ 3,900
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
U.S. Treasury [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 0	$ 0
12 months or longer	124,683	125,024
Total	124,683	125,024
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	0	0
12 months or longer	(8,759)	(8,278)
Total	$ (8,759)	$ (8,278)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	0	0
12 months or longer | Position	8	8
Total | Position	8	8
Federal Agency [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 0	$ 0
12 months or longer	213,304	214,740
Total	213,304	214,740
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	0	0
12 months or longer	(35,071)	(33,644)
Total	$ (35,071)	$ (33,644)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	0	0
12 months or longer | Position	16	16
Total | Position	16	16
State & Municipal [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 0	$ 0
12 months or longer	85,266	85,528
Total	85,266	85,528
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	0	0
12 months or longer	(10,022)	(9,956)
Total	$ (10,022)	$ (9,956)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	0	0
12 months or longer | Position	66	66
Total | Position	66	66
Mortgage-Backed [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 136	$ 53
12 months or longer	404,618	421,259
Total	404,754	421,312
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(1)	(1)
12 months or longer	(52,980)	(51,565)
Total	$ (52,981)	$ (51,566)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	9	7
12 months or longer | Position	158	156
Total | Position	167	163
Collateralized Mortgage Obligations [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 11,033	$ 1,333
12 months or longer	523,989	536,678
Total	535,022	538,011
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(59)	(6)
12 months or longer	(76,110)	(73,351)
Total	$ (76,169)	$ (73,357)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	2	2
12 months or longer | Position	120	118
Total | Position	122	120
Corporate [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 1,459	$ 1,379
12 months or longer	40,419	39,597
Total	41,878	40,976
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(2)	(75)
12 months or longer	(6,571)	(7,391)
Total	$ (6,573)	$ (7,466)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	1	1
12 months or longer | Position	14	14
Total | Position	15	15

Securities, HTM Securities in C

Securities, HTM Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024 USD ($) Position	Dec. 31, 2023 USD ($) Position
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 24,517	$ 26,643
12 months or longer	670,184	675,260
Total	694,701	701,903
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(560)	(492)
12 months or longer	(97,085)	(90,522)
Total	$ (97,645)	$ (91,014)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	6	22
12 months or longer | Position	294	280
Total | Position	300	302
HTM debt securities, nonaccrual	$ 0	$ 0
Accrued interest reversed against interest income	0	0
Collateral-dependent HTM debt securities	0	0
Allowance for credit losses on HTM securities	0	0
AIR on HTM debt securities	$ 5,100	$ 4,700
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Past Due [Member]
Unrealized Loss Position, Number of Positions [Abstract]
HTM debt securities	$ 0	$ 0
Federal Agency [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	0	0
12 months or longer	81,560	82,216
Total	81,560	82,216
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	0	0
12 months or longer	(18,440)	(17,784)
Total	$ (18,440)	$ (17,784)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	0	0
12 months or longer | Position	4	4
Total | Position	4	4
Mortgage-Backed [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 11,905	$ 12,221
12 months or longer	194,181	201,320
Total	206,086	213,541
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(489)	(365)
12 months or longer	(34,434)	(31,814)
Total	$ (34,923)	$ (32,179)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	1	1
12 months or longer | Position	33	33
Total | Position	34	34
Collateralized Mortgage Obligations [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 8,189	$ 0
12 months or longer	213,088	219,820
Total	221,277	219,820
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(58)	0
12 months or longer	(24,614)	(22,929)
Total	$ (24,672)	$ (22,929)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	1	0
12 months or longer | Position	52	54
Total | Position	53	54
State & Municipal [Member]
Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months	$ 4,423	$ 14,422
12 months or longer	181,355	171,904
Total	185,778	186,326
Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	(13)	(127)
12 months or longer	(19,597)	(17,995)
Total	$ (19,610)	$ (18,122)
Unrealized Loss Position, Number of Positions [Abstract]
Less than 12 months | Position	4	21
12 months or longer | Position	205	189
Total | Position	209	210
US Government Agencies Debt Securities and US Government-sponsored Enterprises Debt Securities [Member]
Unrealized Loss Position, Number of Positions [Abstract]
Held-to-maturity debt securities, percentage	66%	66%

Loans (Details)

Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Summary of Loans [Abstract]
Loans	$ 9,688,077	$ 9,650,713
Deferred loan origination (fees) costs, net	89,200	98,200
Commercial and Industrial [Member]
Summary of Loans [Abstract]
Loans	1,353,446	1,354,248
Commercial Real Estate [Member]
Summary of Loans [Abstract]
Loans	3,646,739	3,626,910
Residential Real Estate [Member]
Summary of Loans [Abstract]
Loans	2,133,289	2,125,804
Home Equity [Member]
Summary of Loans [Abstract]
Loans	328,673	337,214
Indirect Auto [Member]
Summary of Loans [Abstract]
Loans	1,190,734	1,130,132
Residential Solar [Member]
Summary of Loans [Abstract]
Loans	896,147	917,755
Other Consumer [Member]
Summary of Loans [Abstract]
Loans	$ 139,049	$ 158,650

Allowance for Credit Losses a_4

Allowance for Credit Losses and Credit Quality of Loans, Summary (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Allowance for Credit Losses [Abstract]
Allowance for credit losses	$ 115,300	$ 115,300	$ 114,400
Percentage of allowance of credit losses	1.19%	1.19%	1.19%
Salisbury Bank [Member]
Allowance for Credit Losses [Abstract]
Loans purchased with credit deterioration	$ 0		$ 219,500
Allowance for credit losses on loans purchased			5,800
Allowance for credit losses at acquisition		$ 14,500
Salisbury Bank [Member] | PCD [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses at acquisition		5,800
Salisbury Bank [Member] | Non-PCD [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses at acquisition		8,800
ASU 2022-02 [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses				$ 100,250	$ 100,152
Loans [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | ASU 2022-02 [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses					(600)
Accrued Interest Receivable [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses	0	0	0
AIR on loans	$ 34,400	$ 34,400	$ 34,100
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets	Other Assets
Residential [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses	$ 23,409	$ 23,409	$ 22,070
Amount of loans purchased	$ 400		$ 3,800
Premium on loans purchased	7%		7%
Allowance for credit losses on loans purchased	$ 4		$ 31
Residential [Member] | ASU 2022-02 [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses				$ 15,390	$ 14,539

Allowance for Credit Losses a_5

Allowance for Credit Losses and Credit Quality of Loans, Allowance for Credit Losses by Portfolio Segments (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period	$ 114,400
Charge-offs	(6,680)		$ (26,778)
Recoveries	2,001
Provision	5,579	$ 3,909
Balance, end of period	115,300		114,400
ASU 2022-02 [Member]
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period		100,152	100,152
Charge-offs		(5,850)
Recoveries		2,039
Provision		3,909
Balance, end of period		100,250
Commercial Loans [Member]
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period	45,903
Charge-offs	(985)
Recoveries	198
Provision	(644)
Balance, end of period	44,472		45,903
Commercial Loans [Member] | ASU 2022-02 [Member]
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period		34,662	34,662
Charge-offs		(169)
Recoveries		541
Provision		1,006
Balance, end of period		36,040
Consumer Loans [Member]
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period	46,427
Charge-offs	(5,581)
Recoveries	1,651
Provision	4,922
Balance, end of period	47,419		46,427
Consumer Loans [Member] | ASU 2022-02 [Member]
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period		50,951	50,951
Charge-offs		(5,342)
Recoveries		1,377
Provision		1,834
Balance, end of period		48,820
Residential [Member]
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period	22,070
Charge-offs	(114)		(517)
Recoveries	152
Provision	1,301
Balance, end of period	$ 23,409		22,070
Residential [Member] | ASU 2022-02 [Member]
Activity in allowance for credit losses by portfolio segment [Roll Forward]
Balance, beginning of period		14,539	$ 14,539
Charge-offs		(339)
Recoveries		121
Provision		1,069
Balance, end of period		$ 15,390

Allowance for Credit Losses a_6

Allowance for Credit Losses and Credit Quality of Loans, Past Due Loans (Details) $ in Thousands	Mar. 31, 2024 USD ($) Relationship	Dec. 31, 2023 USD ($) Relationship
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Threshold balance for loans specifically evaluated for individual credit loss	$ 1,000
Individually evaluated loans, number of relationships | Relationship	2	2
Individually evaluated loans, amortized cost	$ 17,100	$ 17,300
Individually evaluated loans, allowance for credit losses	0	0
Loans in non-accrual without an allowance for credit losses	17,100	17,300
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	35,189	34,213
Recorded total loans	9,688,077	9,650,713
Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	32,277	30,636
31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	23,809	20,585
61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	5,868	6,390
Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	2,600	3,661
Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	9,620,611	9,585,864
C&I [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,404,371	1,397,505
CRE [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	3,445,546	3,433,748
Auto [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,158,073	1,099,442
Residential Solar [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	896,147	917,755
Other Consumer [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	150,765	170,360
Commercial Loans [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	21,822	21,567
Recorded total loans	4,849,917	4,831,253
Commercial Loans [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	4,454	2,086
Commercial Loans [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	3,640	1,217
Commercial Loans [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	814	868
Commercial Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	0	1
Commercial Loans [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	4,823,641	4,807,600
Commercial Loans [Member] | C&I [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	3,079	3,441
Recorded total loans	1,404,371	1,397,505
Commercial Loans [Member] | C&I [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	2,461	448
Commercial Loans [Member] | C&I [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,711	414
Commercial Loans [Member] | C&I [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	750	33
Commercial Loans [Member] | C&I [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	0	1
Commercial Loans [Member] | C&I [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,398,831	1,393,616
Commercial Loans [Member] | CRE [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	18,743	18,126
Recorded total loans	3,445,546	3,433,748
Commercial Loans [Member] | CRE [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,993	1,638
Commercial Loans [Member] | CRE [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,929	803
Commercial Loans [Member] | CRE [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	64	835
Commercial Loans [Member] | CRE [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	0	0
Commercial Loans [Member] | CRE [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	3,424,810	3,413,984
Consumer Loans [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	2,698	2,566
Recorded total loans	2,204,985	2,187,557
Consumer Loans [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	22,939	23,761
Consumer Loans [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	16,370	15,532
Consumer Loans [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	4,196	5,123
Consumer Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	2,373	3,106
Consumer Loans [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	2,179,348	2,161,230
Consumer Loans [Member] | Auto [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	2,274	2,106
Recorded total loans	1,158,073	1,099,442
Consumer Loans [Member] | Auto [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	13,097	13,193
Consumer Loans [Member] | Auto [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	10,376	10,115
Consumer Loans [Member] | Auto [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,676	2,011
Consumer Loans [Member] | Auto [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,045	1,067
Consumer Loans [Member] | Auto [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,142,702	1,084,143
Consumer Loans [Member] | Residential Solar [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	125	245
Recorded total loans	896,147	917,755
Consumer Loans [Member] | Residential Solar [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	5,748	5,290
Consumer Loans [Member] | Residential Solar [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	3,940	3,074
Consumer Loans [Member] | Residential Solar [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,362	1,301
Consumer Loans [Member] | Residential Solar [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	446	915
Consumer Loans [Member] | Residential Solar [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	890,274	912,220
Consumer Loans [Member] | Other Consumer [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	299	215
Recorded total loans	150,765	170,360
Consumer Loans [Member] | Other Consumer [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	4,094	5,278
Consumer Loans [Member] | Other Consumer [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	2,054	2,343
Consumer Loans [Member] | Other Consumer [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	1,158	1,811
Consumer Loans [Member] | Other Consumer [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	882	1,124
Consumer Loans [Member] | Other Consumer [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	146,372	164,867
Residential [Member]
Past Due and Nonperforming Loans [Abstract]
Nonaccrual	10,669	10,080
Recorded total loans	2,633,175	2,631,903
Residential [Member] | Past Due [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	4,884	4,789
Residential [Member] | 31-60 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	3,799	3,836
Residential [Member] | 61-90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	858	399
Residential [Member] | Greater Than 90 Days Past Due Accruing [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	227	554
Residential [Member] | Current [Member]
Past Due and Nonperforming Loans [Abstract]
Recorded total loans	$ 2,617,622	$ 2,617,034

Allowance for Credit Losses a_7

Allowance for Credit Losses and Credit Quality of Loans, Credit Quality Indicators (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Minimum number of days past due for loans to be considered nonperforming	90 days
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	$ 364,006	$ 1,444,621
2023/2022	1,436,145	1,989,711
2022/2021	1,864,247	1,688,309
2021/2020	1,610,531	1,019,863
2020/2019	996,330	692,961
Prior	2,407,804	1,840,266
Revolving Loans Amortized Cost Basis	937,568	920,868
Revolving Loans Converted to Term	71,446	54,114
Total	9,688,077	9,650,713
Gross Charge-offs by Loan Class by Vintage [Abstract]
2024/2023	0	(1,161)
2023/2022	(586)	(9,878)
2022/2021	(3,114)	(9,586)
2021/2020	(1,815)	(1,830)
2020/2019	(376)	(1,805)
Prior	(789)	(2,518)
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	(6,680)	(26,778)
C&I [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	60,820	231,165
2023/2022	219,735	274,930
2022/2021	249,576	243,881
2021/2020	233,859	161,857
2020/2019	150,543	76,826
Prior	137,971	71,313
Revolving Loans Amortized Cost Basis	348,904	333,003
Revolving Loans Converted to Term	2,963	4,530
Total	1,404,371	1,397,505
Gross Charge-offs by Loan Class by Vintage [Abstract]
2024/2023	0	(24)
2023/2022	(9)	(3,021)
2022/2021	(900)	(5)
2021/2020	0	(86)
2020/2019	0	0
Prior	(76)	(600)
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	(985)	(3,736)
C&I [Member] | Pass [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	60,820	229,249
2023/2022	214,985	270,796
2022/2021	243,619	241,993
2021/2020	231,577	158,051
2020/2019	146,409	74,469
Prior	129,310	63,826
Revolving Loans Amortized Cost Basis	318,078	299,248
Revolving Loans Converted to Term	2,585	2,923
Total	1,347,383	1,340,555
C&I [Member] | Special Mention [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	420
2023/2022	1,795	1,672
2022/2021	2,802	277
2021/2020	378	3,524
2020/2019	3,845	87
Prior	1,812	1,854
Revolving Loans Amortized Cost Basis	15,946	19,489
Revolving Loans Converted to Term	251	0
Total	26,829	27,323
C&I [Member] | Substandard [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	1,496
2023/2022	2,934	2,461
2022/2021	3,154	1,609
2021/2020	1,885	282
2020/2019	289	2,266
Prior	6,845	5,632
Revolving Loans Amortized Cost Basis	14,880	14,266
Revolving Loans Converted to Term	127	1,607
Total	30,114	29,619
C&I [Member] | Doubtful [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	0
2023/2022	21	1
2022/2021	1	2
2021/2020	19	0
2020/2019	0	4
Prior	4	1
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	45	8
CRE [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	81,048	357,108
2023/2022	366,262	523,404
2022/2021	499,358	594,415
2021/2020	572,590	460,311
2020/2019	454,540	340,767
Prior	1,103,458	816,067
Revolving Loans Amortized Cost Basis	314,066	307,971
Revolving Loans Converted to Term	54,224	33,705
Total	3,445,546	3,433,748
Gross Charge-offs by Loan Class by Vintage [Abstract]
2024/2023	0	0
2023/2022	0	0
2022/2021	0	0
2021/2020	0	0
2020/2019	0	(114)
Prior	0	(304)
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	0	(418)
CRE [Member] | Pass [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	81,048	353,161
2023/2022	362,660	518,201
2022/2021	492,661	561,897
2021/2020	546,787	452,110
2020/2019	449,533	327,804
Prior	1,013,118	739,189
Revolving Loans Amortized Cost Basis	308,977	294,039
Revolving Loans Converted to Term	37,243	33,705
Total	3,292,027	3,280,106
CRE [Member] | Special Mention [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	3,577
2023/2022	3,602	4,472
2022/2021	5,971	10,711
2021/2020	7,842	7,055
2020/2019	3,875	9,967
Prior	28,841	39,460
Revolving Loans Amortized Cost Basis	3,547	2,970
Revolving Loans Converted to Term	0	0
Total	53,678	78,212
CRE [Member] | Substandard [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	370
2023/2022	0	731
2022/2021	726	21,807
2021/2020	17,961	1,146
2020/2019	1,132	2,996
Prior	61,499	37,418
Revolving Loans Amortized Cost Basis	1,542	10,962
Revolving Loans Converted to Term	16,981	0
Total	99,841	75,430
Auto [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	175,480	474,901
2023/2022	431,015	364,757
2022/2021	332,373	158,081
2021/2020	139,639	42,834
2020/2019	36,234	45,712
Prior	43,332	13,145
Revolving Loans Amortized Cost Basis	0	12
Revolving Loans Converted to Term	0	0
Total	1,158,073	1,099,442
Gross Charge-offs by Loan Class by Vintage [Abstract]
2024/2023	0	(102)
2023/2022	(274)	(1,183)
2022/2021	(493)	(1,066)
2021/2020	(226)	(340)
2020/2019	(12)	(301)
Prior	(122)	(295)
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	(1,127)	(3,287)
Auto [Member] | Performing [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	175,451	474,369
2023/2022	430,001	363,516
2022/2021	331,202	157,251
2021/2020	138,915	42,644
2020/2019	36,140	45,406
Prior	43,045	13,071
Revolving Loans Amortized Cost Basis	0	12
Revolving Loans Converted to Term	0	0
Total	1,154,754	1,096,269
Auto [Member] | Nonperforming [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	29	532
2023/2022	1,014	1,241
2022/2021	1,171	830
2021/2020	724	190
2020/2019	94	306
Prior	287	74
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	3,319	3,173
Residential Solar [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	1,365	155,425
2023/2022	149,789	431,692
2022/2021	422,854	179,044
2021/2020	176,234	65,400
2020/2019	63,222	46,601
Prior	82,683	39,593
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	896,147	917,755
Gross Charge-offs by Loan Class by Vintage [Abstract]
2024/2023	0	(150)
2023/2022	(53)	(1,930)
2022/2021	(910)	(923)
2021/2020	(136)	(45)
2020/2019	0	(558)
Prior	(196)	(345)
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	(1,295)	(3,951)
Residential Solar [Member] | Performing [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	1,365	155,425
2023/2022	149,789	430,855
2022/2021	422,422	178,839
2021/2020	176,158	65,382
2020/2019	63,222	46,554
Prior	82,620	39,540
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	895,576	916,595
Residential Solar [Member] | Nonperforming [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	0
2023/2022	0	837
2022/2021	432	205
2021/2020	76	18
2020/2019	0	47
Prior	63	53
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	571	1,160
Other Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrawn deposit related to gross charge-offs reported as 2022 originations		200
Overdrawn deposit related to gross charge-offs reported as 2023 originations	200	800
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	5,600	13,089
2023/2022	10,564	27,638
2022/2021	22,904	58,561
2021/2020	48,597	21,231
2020/2019	18,068	14,604
Prior	25,976	16,125
Revolving Loans Amortized Cost Basis	19,016	19,046
Revolving Loans Converted to Term	40	66
Total	150,765	170,360
Gross Charge-offs by Loan Class by Vintage [Abstract]
2024/2023	0	(885)
2023/2022	(250)	(3,744)
2022/2021	(811)	(7,511)
2021/2020	(1,453)	(1,329)
2020/2019	(364)	(832)
Prior	(281)	(568)
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	(3,159)	(14,869)
Other Consumer [Member] | Performing [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	5,600	13,089
2023/2022	10,559	27,394
2022/2021	22,720	57,876
2021/2020	47,947	21,087
2020/2019	18,029	14,548
Prior	25,681	15,964
Revolving Loans Amortized Cost Basis	19,015	19,042
Revolving Loans Converted to Term	33	21
Total	149,584	169,021
Other Consumer [Member] | Nonperforming [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	0
2023/2022	5	244
2022/2021	184	685
2021/2020	650	144
2020/2019	39	56
Prior	295	161
Revolving Loans Amortized Cost Basis	1	4
Revolving Loans Converted to Term	7	45
Total	1,181	1,339
Residential [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	39,693	212,933
2023/2022	258,780	367,290
2022/2021	337,182	454,327
2021/2020	439,612	268,230
2020/2019	273,723	168,451
Prior	1,014,384	884,023
Revolving Loans Amortized Cost Basis	255,582	260,836
Revolving Loans Converted to Term	14,219	15,813
Total	2,633,175	2,631,903
Gross Charge-offs by Loan Class by Vintage [Abstract]
2024/2023	0	0
2023/2022	0	0
2022/2021	0	(81)
2021/2020	0	(30)
2020/2019	0	0
Prior	(114)	(406)
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	0
Total	(114)	(517)
Residential [Member] | Performing [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	39,693	212,799
2023/2022	258,154	366,860
2022/2021	336,357	453,206
2021/2020	438,007	267,845
2020/2019	273,451	167,860
Prior	1,006,816	876,563
Revolving Loans Amortized Cost Basis	255,582	260,836
Revolving Loans Converted to Term	14,219	15,300
Total	2,622,279	2,621,269
Residential [Member] | Nonperforming [Member]
Credit Quality by Loan Class by Vintage [Abstract]
2024/2023	0	134
2023/2022	626	430
2022/2021	825	1,121
2021/2020	1,605	385
2020/2019	272	591
Prior	7,568	7,460
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term	0	513
Total	$ 10,896	$ 10,634

Allowance for Credit Losses a_8

Allowance for Credit Losses and Credit Quality of Loans, Allowance for Credit Losses on Off-Balance Sheet Credit Exposures (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Allowance for credit losses	$ 115,300	$ 114,400
Unfunded Commitment [Member]
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Allowance for credit losses	$ 4,700	$ 5,100

Allowance for Credit Losses a_9

Allowance for Credit Losses and Credit Quality of Loans, Amortized Cost Basis of Loans Modified to Borrowers Experiencing Financial Difficulty (Details) - Term Extension [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Modified Loans Disaggregated by Class of Financing Receivable and Type of Concession Granted [Abstract]
Amortized cost	$ 294	$ 43
Residential [Member]
Modified Loans Disaggregated by Class of Financing Receivable and Type of Concession Granted [Abstract]
Amortized cost	$ 294	$ 43
% of total class of financing receivables	0.011%	0.002%

Allowance for Credit Losses _10

Allowance for Credit Losses and Credit Quality of Loans, Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty [Abstract]
Financing receivables with payment default that were modified to borrowers experiencing financial difficulty	$ 0	$ 0
Residential [Member] | Term Extension [Member]
Financing Receivable Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty [Abstract]
Period of increase in weighted-average maturity	7 years 4 months 24 days	18 years

Allowance for Credit Losses _11

Allowance for Credit Losses and Credit Quality of Loans, Performance of Modified Loans (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Current [Member]
Performance of Modified Loans [Abstract]
Amortized cost	$ 863
31-60 Days Past Due [Member]
Performance of Modified Loans [Abstract]
Amortized cost	0
61-90 Days Past Due [Member]
Performance of Modified Loans [Abstract]
Amortized cost	0
Greater Than 90 Days Past Due [Member]
Performance of Modified Loans [Abstract]
Amortized cost	29
Residential [Member] | Current [Member]
Performance of Modified Loans [Abstract]
Amortized cost	863
Residential [Member] | 31-60 Days Past Due [Member]
Performance of Modified Loans [Abstract]
Amortized cost	0
Residential [Member] | 61-90 Days Past Due [Member]
Performance of Modified Loans [Abstract]
Amortized cost	0
Residential [Member] | Greater Than 90 Days Past Due [Member]
Performance of Modified Loans [Abstract]
Amortized cost	$ 29

Short-Term Borrowings (Details)

Short-Term Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Short-Term Debt [Abstract]
Short-term borrowings	$ 267,134	$ 386,651
Federal Funds Purchased [Member]
Short-Term Debt [Abstract]
Short-term borrowings	78,000	0
Securities Sold under Repurchase Agreements [Member]
Short-Term Debt [Abstract]
Short-term borrowings	86,134	93,651
Other Short-Term Borrowings [Member]
Short-Term Debt [Abstract]
Short-term borrowings	$ 103,000	$ 293,000

Defined Benefit Post-Retireme_4

Defined Benefit Post-Retirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Post-Retirement Plans [Abstract]
Employer contributions	$ 0	$ 0
Pension Benefits [Member]
Components of net periodic (benefit) cost [Abstract]
Service cost	514	482
Interest cost	1,005	1,010
Expected return on plan assets	(1,983)	(1,853)
Net amortization	453	670
Total net periodic (benefit) cost	(11)	309
Other Benefits [Member]
Components of net periodic (benefit) cost [Abstract]
Service cost	1	1
Interest cost	55	56
Expected return on plan assets	0	0
Net amortization	(1)	(21)
Total net periodic (benefit) cost	$ 55	$ 36

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Basic EPS [Abstract]
Weighted average common shares outstanding (in shares)	47,148	42,894
Net income available to common stockholders	$ 33,823	$ 33,658
Basic EPS (in dollars per share)	$ 0.72	$ 0.78
Diluted EPS [Abstract]
Weighted average common shares outstanding (in shares)	47,148	42,894
Dilutive effect of common stock options and restricted stock (in shares)	222	232
Weighted average common shares and common share equivalents (in shares)	47,370	43,126
Net income available to common stockholders	$ 33,823	$ 33,658
Diluted EPS (in dollars per share)	$ 0.71	$ 0.78

Reclassification Adjustments _3

Reclassification Adjustments Out of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification Adjustment out of AOCI [Abstract]
Net securities (gains) losses	$ 2,183	$ (4,998)
Interest income	95,174	95,066
Other noninterest expense	6,235	5,080
Income tax (benefit)	9,391	9,586
Net income	33,823	33,658
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Total reclassifications, net of tax	411	4,322
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Income tax (benefit)	(24)	(1,278)
Net income	72	3,836
Losses on AFS Securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Net securities (gains) losses	0	5,000
Amortization of Unrealized Gains Related to Securities Transfer [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Interest income	96	114
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Income tax (benefit)	(113)	(163)
Net income	339	486
Amortization of Net Losses [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Other noninterest expense	454	640
Amortization of Prior Service Costs [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Other noninterest expense	$ (2)	$ 9

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Details) - Derivatives Not Designated as Hedging Instruments [Member] $ in Thousands		3 Months Ended
		Mar. 31, 2024 USD ($) Agreement	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) Agreement
Derivative Asset [Abstract]
Derivatives, fair value		$ 114,289		$ 95,991
Netting adjustments, fair value	[1]	24,321		20,849
Net derivatives in the balance sheet, fair value		89,968		75,142
Derivatives not offset on the balance sheet, fair value		1,924		2,930
Cash collateral, fair value	[2]	0		0
Net derivative amounts, fair value		88,044		72,212
Derivative Liability [Abstract]
Derivatives, fair value		114,104		95,875
Netting adjustments, fair value	[1]	0		0
Net derivatives in the balance sheet, fair value		114,104		95,875
Derivatives not offset on the balance sheet, fair value		1,924		2,930
Cash collateral, fair value	[2]	0		0
Net derivative amounts, fair value		112,180		$ 92,945
Other Income [Member]
Gain or loss recognized in income on derivatives not designating as a hedging relationship [Abstract]
Increase in other income		$ 75	$ 7
Interest Rate Swaps [Member]
Interest rate derivatives [Abstract]
Number of risk participation agreements held | Agreement		13		12
Interest Rate Swaps [Member] | Other Assets [Member]
Derivative Asset [Abstract]
Derivatives, notional amount		$ 1,330,997		$ 1,303,711
Derivatives, fair value		114,205		95,972
Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivative Liability [Abstract]
Derivatives, notional amount		1,330,997		1,303,711
Derivatives, fair value		114,101		95,869
Risk Participation Agreements [Member] | Other Assets [Member]
Derivative Asset [Abstract]
Derivatives, notional amount		71,511		62,112
Derivatives, fair value		84		19
Risk Participation Agreements [Member] | Other Liabilities [Member]
Derivative Liability [Abstract]
Derivatives, notional amount		15,571		16,146
Derivatives, fair value		$ 3		$ 6
[1]Netting adjustments represents the amounts recorded to convert derivatives assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance on the settle to market rules for cleared derivatives. The CME legally characterizes the variation margin posted between counterparties as settlements of the outstanding derivative contracts instead of cash collateral.[2]Cash collateral represents the amount that cannot be used to offset our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The other collateral consists of securities and is exchanged under bilateral collateral and master netting agreements that allow us to offset the net derivative position with the related collateral. The application of the other collateral cannot reduce the net derivative position below zero. Therefore, excess other collateral, if any, is not reflected above.

Fair Value Measurements and F_4

Fair Value Measurements and Fair Value of Financial Instruments, Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
AFS securities [Abstract]
AFS securities	$ 1,418,471	$ 1,430,858
Equity securities	$ 39,470	37,591
Minimum [Member]
Fair Value Measurements [Abstract]
Liquidation expense ratio on impaired collateral	10%
Maximum [Member]
Fair Value Measurements [Abstract]
Liquidation expense ratio on impaired collateral	50%
U.S. Treasury [Member]
AFS securities [Abstract]
AFS securities	$ 124,683	125,024
Federal Agency [Member]
AFS securities [Abstract]
AFS securities	213,304	214,740
State & Municipal [Member]
AFS securities [Abstract]
AFS securities	86,033	86,306
Corporate [Member]
AFS securities [Abstract]
AFS securities	41,878	40,976
Recurring Basis [Member]
AFS securities [Abstract]
AFS securities	1,418,471	1,430,858
Equity securities	39,470	37,591
Derivatives	$ 89,968	$ 75,142
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Total	$ 1,547,909	$ 1,543,591
Liabilities [Abstract]
Derivatives	$ 114,104	$ 95,875
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities
Total	$ 114,104	$ 95,875
Recurring Basis [Member] | Level 1 [Member]
AFS securities [Abstract]
AFS securities	124,683	125,024
Equity securities	38,470	36,591
Derivatives	0	0
Total	163,153	161,615
Liabilities [Abstract]
Derivatives	0	0
Total	0	0
Recurring Basis [Member] | Level 2 [Member]
AFS securities [Abstract]
AFS securities	1,293,788	1,305,834
Equity securities	1,000	1,000
Derivatives	89,968	75,142
Total	1,384,756	1,381,976
Liabilities [Abstract]
Derivatives	114,104	95,875
Total	114,104	95,875
Recurring Basis [Member] | Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Equity securities	0	0
Derivatives	0	0
Total	0	0
Liabilities [Abstract]
Derivatives	0	0
Total	0	0
Recurring Basis [Member] | U.S. Treasury [Member]
AFS securities [Abstract]
AFS securities	124,683	125,024
Recurring Basis [Member] | U.S. Treasury [Member] | Level 1 [Member]
AFS securities [Abstract]
AFS securities	124,683	125,024
Recurring Basis [Member] | U.S. Treasury [Member] | Level 2 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | U.S. Treasury [Member] | Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Federal Agency [Member]
AFS securities [Abstract]
AFS securities	213,304	214,740
Recurring Basis [Member] | Federal Agency [Member] | Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Federal Agency [Member] | Level 2 [Member]
AFS securities [Abstract]
AFS securities	213,304	214,740
Recurring Basis [Member] | Federal Agency [Member] | Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | State & Municipal [Member]
AFS securities [Abstract]
AFS securities	86,033	86,306
Recurring Basis [Member] | State & Municipal [Member] | Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | State & Municipal [Member] | Level 2 [Member]
AFS securities [Abstract]
AFS securities	86,033	86,306
Recurring Basis [Member] | State & Municipal [Member] | Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Mortgage-Backed [Member]
AFS securities [Abstract]
AFS securities	405,547	422,268
Recurring Basis [Member] | Mortgage-Backed [Member] | Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Mortgage-Backed [Member] | Level 2 [Member]
AFS securities [Abstract]
AFS securities	405,547	422,268
Recurring Basis [Member] | Mortgage-Backed [Member] | Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Collateralized Mortgage Obligations [Member]
AFS securities [Abstract]
AFS securities	547,026	541,544
Recurring Basis [Member] | Collateralized Mortgage Obligations [Member] | Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Collateralized Mortgage Obligations [Member] | Level 2 [Member]
AFS securities [Abstract]
AFS securities	547,026	541,544
Recurring Basis [Member] | Collateralized Mortgage Obligations [Member] | Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Corporate [Member]
AFS securities [Abstract]
AFS securities	41,878	40,976
Recurring Basis [Member] | Corporate [Member] | Level 1 [Member]
AFS securities [Abstract]
AFS securities	0	0
Recurring Basis [Member] | Corporate [Member] | Level 2 [Member]
AFS securities [Abstract]
AFS securities	41,878	40,976
Recurring Basis [Member] | Corporate [Member] | Level 3 [Member]
AFS securities [Abstract]
AFS securities	0	0
Non-Recurring Basis [Member]
Fair Value Measurements [Abstract]
Loans individually evaluated for expected credit losses, fair value	$ 0	$ 0

Fair Value Measurements and F_5

Fair Value Measurements and Fair Value of Financial Instruments, Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financial assets [Abstract]
HTM securities	$ 793,319	$ 814,524
Carrying Amount [Member] | Level 1 [Member]
Financial liabilities [Abstract]
Subordinated debt	120,628	120,380
Carrying Amount [Member] | Level 2 [Member]
Financial assets [Abstract]
HTM securities	890,863	905,267
Financial liabilities [Abstract]
Time deposits	1,368,136	1,324,709
Long-term debt	29,759	29,796
Junior subordinated debt	101,196	101,196
Carrying Amount [Member] | Level 3 [Member]
Financial assets [Abstract]
Net loans	9,576,040	9,539,684
Estimated Fair Value [Member] | Level 1 [Member]
Financial liabilities [Abstract]
Subordinated debt	116,563	113,757
Estimated Fair Value [Member] | Level 2 [Member]
Financial assets [Abstract]
HTM securities	793,319	814,524
Financial liabilities [Abstract]
Time deposits	1,348,934	1,285,999
Long-term debt	29,315	29,416
Junior subordinated debt	103,202	102,337
Estimated Fair Value [Member] | Level 3 [Member]
Financial assets [Abstract]
Net loans	$ 9,173,300	$ 9,216,162

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Guarantor Obligations [Abstract]
Obligation instrument term	1 year
Commitment to Extend Credits and Unused Lines of Credit [Member]
Guarantor Obligations [Abstract]
Commitments - maximum potential obligation	$ 2,730	$ 2,250
Standby Letters of Credit [Member]
Guarantor Obligations [Abstract]
Commitments - maximum potential obligation	$ 42	$ 44.7