Cash Flow Information Supplemental Disclosures Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Interest	$ 23,006	$ 14,278	$ 13,323
Income taxes	4,365	6,644	6,760
Capital expenditures included in accounts payable and accrued liabilities	1,326	1,036	2,345
Issuance of shares for asset acquisition	$ 3,000	$ 0	$ 0