Accumulated Other Comprehensive Loss (Tables)

3 Months Ended

Mar. 31, 2025

AOCI Attributable to Parent [Abstract]

Schedule of changes in accumulated other comprehensive income (loss)

			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2024	$	(632,793)	$	168,799	$	(463,994)
Three months ended March 31, 2025
Investment securities:
Unrealized net gains arising during the period		31,363		(8,365)		22,998
Reclassification of net losses to net income:
Amortization of unrealized holding losses on held-to-maturity securities		9,657		(2,576)		7,081
Reclassification of net gains to net income:
Investment securities gains, net		(37)		10		(27)
Net change in investment securities		40,983		(10,931)		30,052
Cash flow derivative hedges:
Unrealized net gains arising during the period		236		(63)		173
Net change in cash flow derivative hedges		236		(63)		173
Other comprehensive income		41,219		(10,994)		30,225
Accumulated other comprehensive loss at March 31, 2025	$	(591,574)	$	157,805	$	(433,769)

			Income
			Tax
	Pre-tax		Benefit		Net of
(dollars in thousands)	Amount		(Expense)		Tax
Accumulated other comprehensive loss at December 31, 2023	$	(723,100)	$	192,890	$	(530,210)
Three months ended March 31, 2024
Investment securities:
Unrealized net losses arising during the period		(3,432)		915		(2,517)
Reclassification of net losses to net income:
Amortization of unrealized holding losses on held-to-maturity securities		11,160		(2,976)		8,184
Net change in investment securities		7,728		(2,061)		5,667
Cash flow derivative hedges:
Unrealized net losses arising during the period		(713)		189		(524)
Reclassification of net losses included in net income		1,755		(468)		1,287
Net change in cash flow derivative hedges		1,042		(279)		763
Other comprehensive income		8,770		(2,340)		6,430
Accumulated other comprehensive loss at March 31, 2024	$	(714,330)	$	190,550	$	(523,780)

Summary of changes in accumulated other comprehensive loss, net of tax

	Pensions								Accumulated
	and		Available-for-Sale		Held-to-Maturity		Cash Flow		Other
	Other		Investment		Investment		Derivative		Comprehensive
(dollars in thousands)	Benefits		Securities		Securities		Hedges		Loss
Three Months Ended March 31, 2025
Balance at beginning of period	$	(1,879)	$	(193,529)	$	(268,501)	$	(85)	$	(463,994)
Other comprehensive income		—		22,971		7,081		173		30,225
Balance at end of period	$	(1,879)	$	(170,558)	$	(261,420)	$	88	$	(433,769)
Three Months Ended March 31, 2024
Balance at beginning of period	$	(5,373)	$	(222,423)	$	(301,611)	$	(803)	$	(530,210)
Other comprehensive (loss) income		—		(2,517)		8,184		763		6,430
Balance at end of period	$	(5,373)	$	(224,940)	$	(293,427)	$	(40)	$	(523,780)