Multipemployer Pension and Postretirement Plans Narrative (Details)	12 Months Ended
	Dec. 31, 2016
Minimum
Multiemployer Plans [Line Items]
Red Zone Multiemployer Plans Funded Percentage	0.00%
Yellow Zone Multiemployer Plans Funded Percentage	65.00%
Green Zone Multiemployer Plan Funded Percentage	80.00%
Maximum
Multiemployer Plans [Line Items]
Red Zone Multiemployer Plans Funded Percentage	65.00%
Yellow Zone Multiemployer Plans Funded Percentage	80.00%
Green Zone Multiemployer Plan Funded Percentage	100.00%