Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Other Changes in Certain Working Capital Accounts, Net
Accounts receivable	$ 41,231	$ (13,756)
Other current assets	(8,435)	3,799
Accounts payable	19,083	15,054
Accrued employee compensation and benefits	(6,575)	(9,191)
Accrued interest	896	329
Other accrued liabilities	(7,533)	(4,231)
Unearned revenue	(1,333)	(4,835)
Other, net	406	(15,456)
Total	$ 37,740	$ (28,287)