Retirement Plans Retirement Plans Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Interest Cost	$ 698	$ 956	$ 923
Defined Benefit Plan, Amortization of Gain (Loss)	1,641	2,886	(1,127)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	2,339	3,842	(204)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	24,961	24,707
Defined Benefit Plan, Interest Cost	698	956	923
Defined Benefit Plan, Actuarial Net (Gains) Losses	1,641	2,886
Defined Benefit Plan, Benefit Obligation, Benefits Paid	2,665	3,588
Defined Benefit Plan, Benefit Obligation	24,635	24,961	24,707
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Amount	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	2,665	3,588
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(24,635)	(24,961)
Defined Benefit Plan, Accumulated Benefit Obligation	24,635	24,961
Liability, Defined Benefit Pension Plan, Current	(2,432)	(2,708)
Liability, Defined Benefit Pension Plan, Noncurrent	(22,203)	(22,253)
Liability, Defined Benefit Pension Plan	(24,635)	(24,961)
Defined Benefit Plan, Estimated Future Retirement Benefits Covered by Insurance Contract, Amount	48,800	47,700
Cash Surrender Value of Life Insurance, Retirement Plans	$ 39,100	$ 38,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.06%	2.95%	4.13%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.98%	4.15%	3.26%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	50.00%
Year One	$ 2,458
Year Two	2,357
Year Three	2,116
Year Four	1,922
Year Five	1,823
Defined Benefit Plan Expected Benefit Payments	18,662
Years 2026 through 2030	7,986
Defined Contribution Plan, Cost	39,800	$ 39,700	$ 36,800
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 2,665	$ 3,588
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	50.00%