Employee Benefit Plans Assumptions Used to Determine Net Periodic Pension Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.00%		4.50%
Discount rate		4.00%
Expected long-term rate of return on plan assets	5.25%	5.25%	5.25%
Other Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actuarial Loss Expected to Occur in the Next 12 Months	Insignificant
Discount rate	3.50%	3.25%	4.00%
Discount rate	3.61%	3.50%	3.25%
Minimum | Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		3.50%
Discount rate	3.70%
Projected annual salary increases-pension cost	0.00%	0.00%	0.00%
Projected annual salary increases	0.00%	0.00%	0.00%
Maximum | Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		3.75%
Discount rate	3.83%
Projected annual salary increases-pension cost	3.00%	3.00%	3.00%
Projected annual salary increases	3.00%	3.00%	3.00%
One-time Termination Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plans, Withdrawal Obligation	$ 3,527	$ 5,500