v3.26.1
Accumulated Other Comprehensive (Loss) Income - Components of Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Accumulated Other Comprehensive Income [Roll Forward]        
Beginning Balance $ 3,505,283 $ 3,274,321 $ 3,490,447 $ 3,197,325
OCI before reclassifications 7,133 (5,313) (20,504) 6,220
Amounts reclassified from AOCI 384 3,849 3,579 7,260
Ending Balance 3,815,813 3,329,246 3,815,813 3,329,246
Unrealized Gains (Losses) on Investment Securities        
Accumulated Other Comprehensive Income [Roll Forward]        
Beginning Balance (226,147) (264,890) (205,701) (275,989)
OCI before reclassifications 12,261 (5,357) (9,422) 4,412
Amounts reclassified from AOCI 0 0 0 2
Ending Balance (212,586) (268,905) (212,586) (268,905)
Net Unrealized Gains (Losses) on Interest Rate Derivatives used in Cash Flow Hedges        
Accumulated Other Comprehensive Income [Roll Forward]        
Beginning Balance (2,259) (10,773) 395 (16,052)
OCI before reclassifications (5,128) 44 (11,082) 1,808
Amounts reclassified from AOCI 474 3,955 3,774 7,470
Ending Balance (6,913) (6,774) (6,913) (6,774)
Unrecognized Pension and Postretirement Plan Income (Costs)        
Accumulated Other Comprehensive Income [Roll Forward]        
Beginning Balance 6,519 4,116 6,624 4,222
OCI before reclassifications 0 0 0 0
Amounts reclassified from AOCI (90) (106) (195) (212)
Ending Balance 6,429 4,010 6,429 4,010
Total        
Accumulated Other Comprehensive Income [Roll Forward]        
Beginning Balance (221,887) (271,547) (198,682) (287,819)
Ending Balance (213,070) (271,669) (213,070) (271,669)
Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income [Roll Forward]        
Amounts reclassified from AOCI 1,300 1,342 2,537 2,670
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Investment Securities        
Accumulated Other Comprehensive Income [Roll Forward]        
Amounts reclassified from AOCI 1,300 1,342 2,537 2,670
Reclassification out of Accumulated Other Comprehensive Income | Net Unrealized Gains (Losses) on Interest Rate Derivatives used in Cash Flow Hedges        
Accumulated Other Comprehensive Income [Roll Forward]        
Amounts reclassified from AOCI 0 0 0 0
Reclassification out of Accumulated Other Comprehensive Income | Unrecognized Pension and Postretirement Plan Income (Costs)        
Accumulated Other Comprehensive Income [Roll Forward]        
Amounts reclassified from AOCI $ 0 $ 0 $ 0 $ 0