Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning and end of year balance	$ 1,900	$ 1,900	$ 1,900