Retirement Plans Retirement Plans Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation	$ 0	$ 0
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Support, Methodology and Source Data	0.5
Defined Benefit Plan, Interest Cost	$ 1,198	1,293	$ 780
Defined Benefit Plan, Amortization of Gains (Losses)	(1,327)	2,401	(1,205)
Defined Benefit Plan, Net Periodic Benefit Cost	(129)	3,694	(425)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	36,920	37,499
Defined Benefit Plan, Interest Cost	1,198	1,293	780
Defined Benefit Plan, Actuarial Net (Gains) Losses	(1,327)	2,401
Defined Benefit Plan, Benefits Paid	(4,486)	(4,273)
Defined Benefit Plan, Benefit Obligation	32,305	36,920	37,499
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	4,486	4,273
Defined Benefit Plan, Benefits Paid	(4,486)	(4,273)
Defined Benefit Plan, Fair Value of Plan Assets	0	0	$ 0
Defined Benefit Plan, Funded Status of Plan	(32,305)	(36,920)
Defined Benefit Plan, Accumulated Benefit Obligation	32,305	36,920
Defined Benefit Pension Plan Liabilities, Current	(3,723)	(4,005)
Defined Benefit Pension Plan, Liabilities, Noncurrent	(28,582)	(32,915)
Defined Benefit Pension Plan, Liabilities	(32,305)	(36,920)
Defined Benefit Plan, Estimated Amount of Plan Participants' Future Benefits Covered by Insurance Contracts Issued by Employer or Related Parties	48,900	47,800
Cash Surrender Value of Life Insurance, Retirement Plans	$ 37,700	$ 37,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.86%	3.42%	3.66%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.47%	3.69%	2.90%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	0.00%
2016	$ 3,723
2017	3,425
2018	3,216
2019	3,146
2020	2,724
Years 2021 through 2025	10,565
Defined Contribution Plan, Cost Recognized	$ 30,800	$ 26,800	$ 24,300