Income Taxes - Valuation Allowance Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in valuation allowance
Beginning Balance	$ 350	$ 482	$ 420
Charge (Credit) to Income Tax Expense or Equity	(15)	(132)	62
Ending Balance	335	350	482
Unrecognized tax benefits	0	0	0
Unrecognized tax benefits, income tax penalties and interest expense	$ 0	$ 0	$ 0