Retirement Plans Retirement Plans Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Support, Methodology and Source Data	0.5
Defined Benefit Plan, Interest Cost	$ 1,179	$ 1,198	$ 1,293
Defined Benefit Plan, Amortization of Gains (Losses)	259	(1,327)	2,401
Defined Benefit Plan, Net Periodic Benefit Cost	1,438	(129)	3,694
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	32,305	36,920
Defined Benefit Plan, Interest Cost	1,179	1,198	1,293
Defined Benefit Plan, Actuarial Net (Gains) Losses	259	(1,327)
Defined Benefit Plan, Benefits Paid	(3,665)	(4,486)
Defined Benefit Plan, Benefit Obligation	30,078	32,305	36,920
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Defined Benefit Plan, Contributions by Employer	3,665	4,486
Defined Benefit Plan, Benefits Paid	(3,665)	(4,486)
Defined Benefit Plan, Fair Value of Plan Assets	0	0	$ 0
Defined Benefit Plan, Funded Status of Plan	(30,078)	(32,305)
Defined Benefit Plan, Accumulated Benefit Obligation	30,078	32,305
Defined Benefit Pension Plan Liabilities, Current	(3,448)	(3,723)
Defined Benefit Pension Plan, Liabilities, Noncurrent	(26,630)	(28,582)
Defined Benefit Pension Plan, Liabilities	(30,078)	(32,305)
Defined Benefit Plan, Estimated Amount of Plan Participants' Future Benefits Covered by Insurance Contracts Issued by Employer or Related Parties	47,500	48,900
Cash Surrender Value of Life Insurance, Retirement Plans	$ 37,000	$ 37,700
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.76%	3.86%	3.42%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.96%	2.47%	3.69%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	0.00%
Year One	$ 3,448
Year Two	3,237
Year Three	3,166
Year Four	2,739
Year Five	2,428
Years 2022 through 2026	9,959
Defined Contribution Plan, Cost Recognized	$ 32,500	$ 30,800	$ 26,800