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v3.25.3

Business Combinations - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 3 Months Ended | 9 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 01, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Aug. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Business Combination [Line Items] |  |  |  |  |  |  |  |
Common stock, par value (in dollars per share) |  | $ 0.01 |  | $ 0.01 |  |  | $ 0.01 |
Goodwill |  | $ 353,471 |  | $ 353,471 |  |  | $ 241,222 | $ 241,222
Non-PCD loans acquired | $ 8,520,000 |  |  |  |  |  |  |
Acquisition-related cost |  | 45,863 | $ 0 | 47,273 | $ 823 |  |  |
Core deposits |  |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |  |
Intangible asset, useful life | 12 years |  |  |  |  |  |  |
Customer relationships intangible asset |  |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |  |
Intangible asset, useful life | 12 years |  |  |  |  |  |  |
Brookline Bancorp, Inc. |  |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |  |
Common stock, par value (in dollars per share) | $ 0.01 |  |  |  |  |  |  |
Holdco Merger |  |  |  |  |  |  |  |
Business Combination [Line Items] |  |  |  |  |  |  |  |
Common stock, par value (in dollars per share) | $ 0.01 |  |  |  |  |  |  |
Equity shares issued per acquiree share (in shares) | 0.42 |  |  |  |  |  |  |
Share issued (in shares) | 37,700,000 |  |  |  |  |  |  |
Voting equity interest acquired, percentage | 45.00% |  |  |  |  | 100.00% |  |
Goodwill | $ 112,248 |  |  |  |  |  |  |
Allowance for credit losses, non-PCD loans | $ 67,200 |  |  |  |  |  |  |
Acquisition-related cost |  | $ 45,900 |  | $ 47,300 |  |  |  |

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