Organization and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 49,956	$ 34,598
Restricted cash	61,394	54,106
Total cash, cash equivalents, and restricted cash shown on consolidated statement of cash flows	$ 111,350	$ 88,704	$ 217,958	$ 87,200