Qualified Employee Benefit Plans - Net (Benefit) Expense Under the Retirement Plan (Details) - Retirement Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost on projected benefit obligations	$ 3,958	$ 3,794	$ 4,443
Expected return on plan assets	(6,591)	(6,351)	(6,084)
Amortization of prior service cost	24	24	24
Settlement loss recognized	1,678	2,024	0
Recognized actuarial loss	1,042	1,447	1,386
Net pension expense	$ 111	$ 938	$ (231)