Supplemental Cash Flow Information - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 184,620	$ 164,798	$ 78,687	$ 138,285
Total cash, cash equivalents, and restricted cash reported in the statements of cash flows	186,808	169,745	83,256	143,775
Prepaid Expenses and Other Current Assets
Cash and Cash Equivalents [Line Items]
Restricted cash	1,275	4,026	3,286	5,106
Other Assets, Net
Cash and Cash Equivalents [Line Items]
Restricted cash	$ 913	$ 921	$ 1,283	$ 384