Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net income	$ 90,271,000	$ 68,715,000	$ 74,999,000
Adjustments to reconcile net income to net cash provided from operating activities:
Provision for credit losses	41,392,000	21,644,000	38,207,000
Proceeds from sales of loans and leases held-for-sale, net	83,330,000	0	0
Deferred income tax expense	22,348,000	409,000	16,167,000
Depreciation of premises and equipment	9,553,000	7,890,000	8,159,000
Accretion of investment securities deferred, net	(9,953,000)	(5,657,000)	(8,658,000)
Accretion of premiums and discounts and deferred loan and lease origination costs, net	(20,885,000)	(6,682,000)	(4,708,000)
Amortization of identified intangible assets	15,225,000	6,746,000	7,840,000
Amortization of debt issuance costs	100,000	100,000	100,000
Amortization (accretion) of other acquisition fair value adjustments, net	(1,749,000)	1,313,000	(1,611,000)
Gain on sales of investment securities, net	0	0	(1,704,000)
Gain on sales of loans and leases	(5,617,000)	(951,000)	(2,581,000)
Loss on sales of OREO and other repossessed assets	153,000	0	4,000
Write-down of OREO and other repossessed assets	412,000	574,000	181,000
Compensation under recognition and retention plans	5,919,000	3,380,000	3,723,000
Net change in:
Cash surrender value of bank-owned life insurance	(3,015,000)	(2,017,000)	(1,269,000)
Impairment of BankRI trade name	1,089,000	0	0
Other assets	85,243,000	6,590,000	13,758,000
Accrued expenses and other liabilities	(89,372,000)	2,900,000	(26,010,000)
Net cash provided from operating activities	224,444,000	104,954,000	116,597,000
Cash flows from investing activities:
Proceeds from sales of investment securities available-for-sale	176,312,000	0	229,981,000
Proceeds from maturities, calls, and principal repayments of investment securities available-for-sale	189,964,000	173,996,000	272,419,000
Purchases of investment securities available-for-sale	(33,126,000)	(148,476,000)	(362,905,000)
Proceeds from redemption/sales of restricted equity securities	83,643,000	32,834,000	48,489,000
Purchase of restricted equity securities	(60,488,000)	(38,394,000)	(50,775,000)
Proceeds from sales of loans and leases held-for-investment, net	300,822,000	109,742,000	244,133,000
Net decrease (increase) in loans and leases	570,003,000	(265,919,000)	(955,593,000)
Net cash and cash equivalents acquired in acquisition	1,084,095,000	0	(80,209,000)
Purchase of premises and equipment, net	(12,288,000)	(4,985,000)	(12,357,000)
Proceeds from sales of OREO and other repossessed assets	1,473,000	1,599,000	1,552,000
Net cash provided from (used for) investing activities	2,300,410,000	(139,603,000)	(665,265,000)
Cash flows from financing activities:
Increase (decrease) in demand checking, NOW, savings and money market accounts	1,061,533,000	5,424,000	(402,552,000)
(Decrease) increase in certificates of deposit and brokered certificates of deposit	(733,392,000)	347,057,000	859,866,000
Proceeds from FHLB advances	1,057,750,000	1,643,100,000	6,155,000,000
Repayment of FHLB advances	(2,300,715,000)	(1,510,516,000)	(6,222,735,000)
(Decrease) increase in other borrowed funds, net	(46,469,000)	10,336,000	(41,529,000)
Decrease in mortgagors' escrow accounts, net	(367,000)	(1,364,000)	(678,000)
Payment of dividends on common stock	(63,119,000)	(48,058,000)	(47,926,000)
Payment of income taxes for shares withheld in share based activity	(2,000,000)	(687,000)	(710,000)
Net cash (used for) provided from financing activities	(1,026,779,000)	445,292,000	298,736,000
Net increase (decrease) in cash and cash equivalents	1,498,075,000	410,643,000	(249,932,000)
Cash and cash equivalents at beginning of year	543,670,000	133,027,000	382,959,000
Cash and cash equivalents at end of year	2,041,745,000	543,670,000	133,027,000
Cash paid during the year for:
Interest on deposits, borrowed funds and subordinated debt	328,862,000	291,428,000	238,396,000
Income taxes	14,968,000	13,085,000	8,632,000
Non-cash investing activities:
Transfer from loans and leases to loan and leases held-for-sale	(79,859,000)	0	0
Transfer from loans to OREO and other repossessed assets	1,142,000	1,582,000	3,023,000
Acquisitions of Berkshire Hills Bancorp, Inc. in 2025 and PCSB Financial Corporation in 2023:
Fair value of assets acquired, net of cash and cash equivalents acquired	11,170,597,000	0	1,931,528,000
Fair value of liabilities assumed	11,044,057,000	0	1,676,110,000
Common stock issued			167,330,000
Common Stock
Acquisitions of Berkshire Hills Bancorp, Inc. in 2025 and PCSB Financial Corporation in 2023:
Common stock issued	$ 0	$ 0	$ 118,000