Pension and Other Postretirement Plans (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) benefit_plan	Mar. 31, 2019 USD ($)	Dec. 31, 2007
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of non-qualified defined benefit pension plans | benefit_plan	3
Number of healthcare plans | benefit_plan	2
Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Vesting percentage in accrued benefits from plan freeze			100.00%
Service cost	$ 27	$ 24
Interest cost	168	210
Expected return on plan assets	(315)	(272)
Amortization of net loss	145	165
Net periodic benefit cost	25	127
Minimum required contribution	0
Planned contributions remaining	800
Company contributions to plan	100
Chairman and President Non-Qualified Defined Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	302	125
Interest cost	338	256
Amortization of prior service cost	15	15
Amortization of net loss	1,445	348
Net periodic benefit cost	2,100	744
Company contributions to plan	400
Company expected contributions to plans in fiscal year	2,000
Defined Benefit Postretirement Healthcare Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	41	49
Amortization of prior service cost	0	13
Amortization of net loss	40	61
Net periodic benefit cost	$ 81	$ 123
Minimum | Chairman and President Non-Qualified Defined Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Aggregate average annual participant salary increase	10.00%