Supplemental Cash Flow Information - Cash Paid for Interest and Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Information [Abstract]
Interest (net of amounts capitalized)	$ 23,882	$ 23,098	$ 17,362
Net income taxes paid (refunds received)	$ 1,045	$ (5,271)	$ (7,755)