Basis of Presentation and Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right of use assets	$ 6,940	$ 8,289
Operating lease, liability	$ 7,149		$ 0
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right of use assets		8,289
Operating lease, liability		$ 8,300