Benefit Plans (Tables)	12 Months Ended
Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Schedule of contributions made to multi-employer plans	an. Contributions we made to the multi-employer plans for the years ended December 31, 2016, 2015 and 2014 are included in the table below (in thousands

Tabular disclosure of the quantitative and qualitative information related to multiemployer plans in which the employer participates. 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 5
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

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