Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stockholders' Equity Attributable to Parent	$ (293,735)	$ (270,678)	$ (267,328)	$ (279,003)
Accumulated Translation Adjustment [Member]
Stockholders' Equity Attributable to Parent	2,742	2,623	2,685
Net current period other comprehensive gain (loss)	119	(62)
Reclassification of accumulated other comprehensive income (loss)	0	0
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Stockholders' Equity Attributable to Parent	37	0	(33)
Net current period other comprehensive gain (loss)	37	33
Reclassification of accumulated other comprehensive income (loss)	0	0
Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders' Equity Attributable to Parent	2,779	2,623	$ 2,652	$ 1,795
Net current period other comprehensive gain (loss)	156	(29)
Reclassification of accumulated other comprehensive income (loss)	$ 0	$ 0