General Significant Accounting Policies (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Cash and cash equivalents	$ 30,543	$ 22,058
Long-term restricted cash equivalents	6,336	6,336
Total cash, cash equivalents and restricted cash equivalents	$ 36,879	$ 28,394	$ 28,163	$ 32,838