Income Taxes, Change in Deferred Tax Valuation Allowance (Details 2) - Income tax valuation allowance - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation allowance
Balance at Beginning of Period	$ 44,309	$ 34,921	$ 23,864
Additions Charged to Expense/Against Revenue	10,430	9,388	11,057
Balance at End of Period	$ 54,739	$ 44,309	$ 34,921