Leases Lease Cost (Details) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($)
Components of Lease Cost [Line Items]
Short-Term Operating Lease Expense	$ 3,403
Lease Term, Greater than 12 Months [Member]
Components of Lease Cost [Line Items]
Long-Term Operating Lease Expense	$ 842

Amount of short-term lease cost, excluding expense for lease with term of one month or less.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971

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