Unaudited Condensed Consolidated Statements of Cash Flows - Supplemental - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Supplemental disclosures:
Cash and cash equivalents	$ 281,691	$ 176,000
Restricted cash (Note 1)	107	109
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	281,798	176,109
Cash paid for income taxes, net of refunds	5,016	7,678
Non-cash transactions
Property and equipment purchases in accounts payable and accrued liabilities	$ 1,211	$ 1,734