Contractual Obligations and Commitments - Summary of Other Information related to Operating Leases (Parenthetical) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Current portion of operating lease liabilities	$ 1,300
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent
Long-term portion of lease liabilities	$ 15,018	$ 4,442

No definition available.

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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease, classified as current.

+ References

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

+ Details

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- Definition

Indicates line item in statement of financial position that includes current operating lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918631-209977

+ Details

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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.

+ References

+ Details

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Period Type:	instant