STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 163,903	$ 117,852	$ 288,455	$ 204,093
Other comprehensive (loss) income, net of tax
Change in unrealized holding gains (losses) on available-for-sale securities	1,541	(1,746)	787	8,748
Pension and other postretirement plans	(3,434)	(2,742)	(4,510)	(5,484)
Total other comprehensive (loss) income, net of tax	(1,893)	(4,488)	(3,723)	3,264
Comprehensive income	$ 162,010	$ 113,364	$ 284,732	$ 207,357