Commitments and Contingencies (Collective Bargaining Agreements and Multiemployer Plans) (Narrative) (Details) - Central States [Member] - Multiemployer Plans, Pension [Member] - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Dec. 31, 2015	Nov. 30, 2011
Loss Contingencies [Line Items]
Multiemployer plan, withdrawal obligation, payments	$ 3.0
Multiemployer plans, withdrawal liability		$ 3.0	$ 6.4

Amount of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

No definition available.

Name:	us-gaap_MultiemployerPlansWithdrawalObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant