Pension Plan and Employee Benefits - 401 (K) Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense	$ 7,770	$ 7,310	$ 7,780
Support Group
Defined Contribution Plan Disclosure [Line Items]
401(k) Plan expense	$ 2,859	$ 2,685	$ 2,765