Retirement Plans Retirement Plans Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Interest Cost	$ 956	$ 923	$ 1,067
Defined Benefit Plan, Amortization of Gain (Loss)	2,886	(1,127)	879
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	3,842	(204)	1,946
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	24,707	28,681
Defined Benefit Plan, Interest Cost	956	923	1,067
Defined Benefit Plan, Actuarial Net (Gains) Losses	2,886	(1,127)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	3,588	3,770
Defined Benefit Plan, Benefit Obligation	24,961	24,707	28,681
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	3,588	3,770
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(24,961)	(24,707)
Defined Benefit Plan, Accumulated Benefit Obligation	24,961	24,707
Liability, Defined Benefit Pension Plan, Current	(2,708)	(3,175)
Liability, Defined Benefit Pension Plan, Noncurrent	(22,253)	(21,532)
Liability, Defined Benefit Pension Plan	(24,961)	(24,707)
Defined Benefit Plan, Estimated Future Retirement Benefits Covered by Insurance Contract, Amount	47,700	47,100
Cash Surrender Value of Life Insurance, Retirement Plans	$ 38,000	$ 37,200
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.95%	4.13%	3.41%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	4.15%	3.26%	3.86%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	50.00%
Year One	$ 2,742
Year Two	2,410
Year Three	2,337
Year Four	2,095
Year Five	1,902
Defined Benefit Plan Expected Benefit Payments	19,821
Years 2025 through 2029	8,335
Defined Contribution Plan, Cost	39,700	$ 36,800	$ 33,200
Defined Benefit Plan, Plan Assets, Benefits Paid	$ 3,588	$ 3,770
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	50.00%