Summary of Significant Accounting Policies (Accounting Standards Adopted in 2018) (Details) $ in Thousands	Jan. 01, 2018 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment on adoption of new accounting standard for revenue recognition	$ 295
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment on adoption of new accounting standard for revenue recognition	295
Retained Earnings | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment on adoption of new accounting standard for revenue recognition	$ 295