Postretirement Benefit Plans (Details) - Multiemployer Health and Welfare Plan [Member]	7 Months Ended	12 Months Ended	17 Months Ended
Dec. 31, 2015 USD ($) employee	Dec. 31, 2015 USD ($) employee	May. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) employee	Dec. 31, 2013 USD ($) employee	May. 31, 2014 USD ($)
Multiemployer Plans [Line Items]
Number of employees in plan \| employee	651	651		652	625
Required employer's contribution per hour per active employee	$ 5.50		$ 5.25			$ 5.00
Period Contributions		$ 7,600,000		$ 7,300,000	$ 6,900,000

Amount of contributions made to multiemployer plans by the employer. A multiemployer plan is 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=49170332&loc=SL14450702-114947

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=49170332&loc=SL14450691-114947

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=49170332&loc=SL14450657-114947

Name:	us-gaap_MultiemployerPlanPeriodContributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration