Accumulated Other Comprehensive Income (Loss) - Schedule of accumulated other comprehensive income (loss) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	$ 1,365,580
Ending Balance	1,463,994
Accumulated Other Comprehensive Income (loss)
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	61,429
Unrealized (losses)	(37)
Amounts reclassified from accumulated other comprehensive income (loss)	(2,873)
Tax effect	639
Ending Balance	59,158
Pension, Postretirement and Other Post-Employment Benefits
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	61,485
Amounts reclassified from accumulated other comprehensive income (loss)	(2,895)
Tax effect	636
Ending Balance	59,226
Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	(56)
Unrealized (losses)	(37)
Amounts reclassified from accumulated other comprehensive income (loss)	22
Tax effect	3
Ending Balance	$ (68)