Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1,	$ 265	$ 265	$ 265
Additions based on tax positions related to the current year	0	0	0
Additions for tax positions of prior years	59	0	0
Reductions for tax positions of prior years	0	0	0
Settlements	0	0	0
Balance at December 31,	$ 324	$ 265	$ 265