Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 57,415	$ 28,916	$ 48,423	$ 64,609
Debt securities available-for-sale:
Net change in unrealized gains (losses) on debt securities available-for-sale	24,533	(210)	61,558	(11,113)
Related income tax effect	(7,103)	50	(15,992)	2,835
Net securities (gains) losses reclassified into earnings	(9)	12	(50)	12
Related income tax effect	(207)	(61)	(253)	(119)
Net effect on other comprehensive income (loss) for the period	17,214	(209)	45,263	(8,385)
Defined benefit plans:
Amortization of net gain and prior service costs	(194)	(101)	(366)	(202)
Related income tax effect	46	24	91	72
Net effect on other comprehensive loss for the period	(148)	(77)	(275)	(130)
Total other comprehensive income (loss)	17,066	(286)	44,988	(8,515)
Comprehensive income	$ 74,481	$ 28,630	$ 93,411	$ 56,094