Accounting Policies and Basis of Presentation - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Debt instrument, fair value disclosure	$ 42,374		$ 32,018
Long-term debt	42,489		32,014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use asset, net	6,163		0
Operating lease liability	$ 4,112		$ 0
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use asset, net		$ 6,598
Operating lease liability		$ 6,952