Postretirement Benefit Obligations - Defined Benefit Plans Disclosure (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in benefit obligation:
Benefit obligation at beginning balance				$ 80,174				$ 91,389				$ 89,137	$ 80,174	$ 91,389	$ 89,137
Service Cost													4,906	6,860	7,817
Interest Cost													4,048	2,436	2,071
Actuarial losses (gains)													6,636	(18,665)	(6,342)
Benefits Paid													(2,494)	(1,846)	(1,294)
Benefit obligation at ending balance	$ 93,270				$ 80,174				$ 91,389				93,270	80,174	91,389
Change in plan assets:
Fair value of plan assets at beginning balance				77,362				71,252				48,444	77,362	71,252	48,444
Actual return on plan assets													11,216	(12,044)	6,572
Benefits paid													(2,494)	(1,846)	(1,294)
Company Contributions	0	$ 0	$ 0	$ 0	5,000	$ 5,000	$ 10,000	$ 0	0	$ 12,710	$ 3,620	$ 1,200	0	20,000	17,530
Fair value of plan assets at ending balance	86,084				77,362				71,252				86,084	77,362	71,252
Under-Funded status of plan	7,186				2,812				20,137				7,186	2,812	20,137
Accrued pension liabilities-current	3,526				2,812				1,894				3,526	2,812	1,894
Accrued pension liabilities-noncurrent	3,660				0				18,243				3,660	0	18,243
Total pension liabilities recognized	$ 7,186				$ 2,812				$ 20,137				$ 7,186	$ 2,812	$ 20,137