Employee Benefit Plans - Funded Status of Pension Plan and Post-Retirement Medical Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits
Change in Projected Benefit Obligation:
Projected benefit obligation at beginning of year	$ 259,751	$ 272,786
Service cost	5,644	6,316	$ 5,558
Interest cost	7,401	6,833	7,880
Actuarial (gain) loss	(72,710)	(17,682)
Benefits/expenses paid	(9,408)	(8,502)
Projected benefit obligation at end of year	190,678	259,751	272,786
Changes in Plan Assets:
Fair value of plan assets at beginning of year	233,524	213,147
Actual return on plan assets	(40,299)	25,390
Employer contributions	3,089	3,489
Benefits/expenses paid	(9,408)	(8,502)
Fair value of plan assets at end of year	186,906	233,524	213,147
Funded Status:
Net amount recognized as accrued pension cost	(3,772)	(26,227)
Post-Retirement Medical Benefits
Change in Projected Benefit Obligation:
Projected benefit obligation at beginning of year	2,686	5,906
Service cost	129	149	171
Interest cost	60	110	208
Actuarial (gain) loss	(570)	(3,165)
Benefits/expenses paid	(291)	(314)
Projected benefit obligation at end of year	2,014	2,686	5,906
Changes in Plan Assets:
Fair value of plan assets at beginning of year	13,773	12,313
Actual return on plan assets	(2,242)	1,773
Employer contributions	263	242
Benefits/expenses paid	(554)	(555)
Fair value of plan assets at end of year	11,240	13,773	$ 12,313
Funded Status:
Net amount recognized as accrued pension cost	$ 9,226	$ 11,087