Accounting Policies and Basis of Presentation - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Debt instrument, fair value disclosure	$ 42,350		$ 32,018
Long-term debt	41,326		32,014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use asset, net (Note 6)	5,628		0
Operating lease liability (Note 6)	$ 3,598		$ 0
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use asset, net (Note 6)		$ 6,598
Operating lease liability (Note 6)		$ 6,952