Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Abstract
Cash and cash equivalents	$ 76,190	$ 82,936
Restricted Cash	1,753	1,012
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 77,943	$ 83,948	$ 75,879	$ 51,964