Employee Benefit Plans - Additional Information (Details) $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($)
Retirement Benefits [Abstract]
Expected contributions to all plans in 2018	$ 3,200
Unfunded liability on multiemployer plan	13,700
Monthly installments on multiemployer plan	$ 38
Contribution term of multiemployer plan	30 years

Amount of contributions expected to be received by defined benefit plan from employer in fiscal year. Excludes contributions paid by employer in current fiscal year.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2709-114920

Name:	us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant