Organization and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 165,126	$ 40,867
Restricted cash	52,832	46,333
Total cash, cash equivalents, and restricted cash shown on consolidated statement of cash flows	$ 217,958	$ 87,200	$ 146,240	$ 98,889