Overview and Summary of Significant Accounting Policies - Schedule of Cash and Cash Equivalents and Restricted Cash Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 39,545	$ 61,999
Restricted cash included in other current assets	$ 2,426	$ 5
Restricted Cash and Cash Equivalents, Current, Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherCurrentAssetsMember	us-gaap:OtherCurrentAssetsMember
Cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 41,971	$ 62,004	$ 44,899	$ 53,729