Commitments and Contingencies Health Benefit Plan Costs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
US Employee Group Health Insurance Expense	$ 7,923	$ 7,673	$ 14,801	$ 16,354

Amount of labor-related expenses classified as other.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

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