Employee Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Components of net periodic benefit cost
Recognized net actuarial gain due to curtailments	$ 0	$ 0	$ 302
DB Pension Plan
Components of net periodic benefit cost
Service cost	0	0	0
Interest cost	1,628	2,371	2,936
Expected return on plan assets	(5,652)	(5,416)	(4,933)
Amortization of prior service (credit) cost	1	(10)	(10)
Recognized net actuarial loss	1,559	1,411	1,334
Recognized net actuarial gain due to curtailments	0	0	0
Net periodic benefit (credit) cost	(2,464)	(1,644)	(673)
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss)
Net actuarial loss (gain)	(8,209)	3,899	2,776
Recognized actuarial loss	(1,559)	(1,411)	(1,334)
Prior service credit	0	0	0
Recognized prior service cost (credit)	(1)	10	10
Prior service cost (credit) recognized due to curtailment	0	0	0
Recognized in other comprehensive income (loss)	(9,769)	2,498	1,452
Total recognized in net periodic benefit cost and other comprehensive income (loss)	(12,233)	854	779
Life and Healthcare Plan
Components of net periodic benefit cost
Service cost	186	173	159
Interest cost	180	245	289
Expected return on plan assets	0	0	0
Amortization of prior service (credit) cost	(61)	(61)	(62)
Recognized net actuarial loss	312	155	0
Recognized net actuarial gain due to curtailments	0	0	(399)
Net periodic benefit (credit) cost	617	512	(13)
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss)
Net actuarial loss (gain)	(574)	1,340	1,218
Recognized actuarial loss	(312)	(155)	0
Prior service credit	0	0	(203)
Recognized prior service cost (credit)	61	61	62
Prior service cost (credit) recognized due to curtailment	0	0	399
Recognized in other comprehensive income (loss)	(825)	1,246	1,476
Total recognized in net periodic benefit cost and other comprehensive income (loss)	(208)	1,758	1,463
SERP Plan
Components of net periodic benefit cost
Service cost	231	214	157
Interest cost	692	914	909
Expected return on plan assets	0	0	0
Amortization of prior service (credit) cost	282	285	104
Recognized net actuarial loss	1,080	800	343
Recognized net actuarial gain due to curtailments	0	0	0
Net periodic benefit (credit) cost	2,285	2,213	1,513
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss)
Net actuarial loss (gain)	(3,002)	4,070	6,128
Recognized actuarial loss	(1,080)	(800)	(343)
Prior service credit	0	0	2,022
Recognized prior service cost (credit)	(282)	(285)	(104)
Prior service cost (credit) recognized due to curtailment	0	0	0
Recognized in other comprehensive income (loss)	(4,364)	2,985	7,703
Total recognized in net periodic benefit cost and other comprehensive income (loss)	$ (2,079)	$ 5,198	$ 9,216