Summary of Significant Accounting Policies - Schedule of Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 15,804	$ 19,959	$ 10,039	$ 21,942
Restricted cash	3,502	2,957	3,649	3,251
Cash, cash equivalents, and restricted cash	$ 19,306	$ 22,916	$ 13,688	$ 25,193