Financial Instruments and Risk Management (Tables)

6 Months Ended

Jun. 30, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Value of Derivative Instruments Not Designated as Hedging Instruments

At June 30, 2019 and December 31, 2018, the fair value of derivative instruments not designated as hedging instruments are presented in the following table.

	June 30, 2019			December 31, 2018
(Thousands of dollars)	Asset (Liability) Derivatives			Asset (Liability) Derivatives
Type of Derivative Contract	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
Commodity	Accounts receivable	$	56,193	Accounts receivable	$	3,837

Recognized Gains and Losses for Derivative Instruments Not Designated as Hedging Instruments

For the three-month and six-month periods ended June 30, 2019 and June 30, 2018 the gains and losses recognized in the Consolidated Statements of Operations for derivative instruments not designated as hedging instruments are presented in the following table.

		Gain (Loss)				Gain (Loss)
(Thousands of dollars)		Three Months Ended June 30,				Six months ended June 30,
Type of Derivative Contract	Statement of Operations Location	2019		2018		2019	2018
Commodity	Gain (loss) on crude contracts	$	57,916	(37,624	)	57,916	(67,126	)

Carrying Value of Assets and Liabilities Recorded at Fair Value on Recurring Basis

The carrying value of assets and liabilities recorded at fair value on a recurring basis at June 30, 2019 and December 31, 2018 are presented in the following table.

	June 30, 2019					December 31, 2018
(Thousands of dollars)	Level 1		Level 2	Level 3	Total	Level 1	Level 2	Level 3	Total
Assets:
Commodity derivative contracts	$	—	56,193	—	56,193	—	3,837	—	3,837
	$	—	56,193	—	56,193	—	3,837	—	3,837
Liabilities:
Nonqualified employee savings plans	$	16,061	—	—	16,061	13,845	—	—	13,845
Contingent consideration	—		—	178,409	178,409	—	—	47,730	47,730
	$	16,061	—	178,409	194,470	13,845	—	47,730	61,575