Basis of Financial Statement Presentation (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Mar. 31, 2019
ASU 2018-02
Basis of Financial Statement Presentation
Reclassification from accumulated other comprehensive loss to retained earnings	$ 66
Forecast \| ASU 2016-02
Basis of Financial Statement Presentation
Finance obligation under lease agreements		$ 1,000

Present value of lessee's discounted obligation for lease payments from finance lease.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980

Name:	us-gaap_FinanceLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant