Other Financial Information (Tables)

3 Months Ended

Mar. 31, 2019

Other Financial Information [Abstract]

Noncash Operating Working Capital (Increase) Decrease

	Three Months Ended March 31,
(Thousands of dollars)	2019		2018
Net (increase) decrease in operating working capital other than    cash and cash equivalents:
(Increase) decrease in accounts receivable	$	(112,673)	4,227
Decrease in inventories		3,930	15,637
(Increase) decrease in prepaid expenses		(10,763)	3,446
Increase (decrease) in accounts payable and accrued liabilities		21,131	(26,908)
Increase(decrease) in income taxes payable		(130)	45
Net (increase) decrease in noncash operating working capital	$	(98,505)	(3,553)
Supplementary disclosures:
Cash income taxes paid, net of refunds	$	–	(1,104)
Interest paid, net of amounts capitalized of $0 in 2019 and 2018		39,024	35,158
Non-cash investing activities:
Asset retirement costs capitalized	$	486	727
(Increase) decrease in capital expenditure accrual		(63,328)	(17,592)