Derivatives Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2018

Derivative [Line Items]

Schedule of derivative financial instruments

	Floor			Ceiling
Settlement Period	Notional Amount	Weighted-Average per Barrel		Notional Amount	Weighted-Average per Barrel
	(barrels in thousands)			(barrels in thousands)
2018 collar positions(1)	132	$	55.00	132	$	76.00
2019 collar positions(2)	252	$	55.00	252	$	76.00
Total	384			384

(1)Represents 100% of expected diesel consumption for the remainder of 2018.

(2)Represents 50% of expected diesel consumption for 2019.

Schedule of offsetting and balance sheet presentation

	September 30, 2018
	Gross Amounts Recognized				Gross Amounts Offset in the Consolidated Balance Sheet				Net Amounts Presented in the Consolidated Balance Sheet
	Assets		Liabilities		Assets		Liabilities		Assets		Liabilities
WTI derivative financial instruments	$	730	$	—	$	—	$	—	$	730	$	—

December 31, 2017

Gross Amounts Recognized

Gross Amounts Offset in the Consolidated Balance Sheet

Net Amounts Presented in the Consolidated Balance Sheet

Assets

Liabilities

Assets

Liabilities

Assets

Liabilities

WTI derivative financial instruments

$

—

$

—

$

—

$

—

$

—

$

—

Schedule of derivative mark-to-market (gains) and losses recognized in the consolidated statement of operations and comprehensive income

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2018		2017		2018		2017
WTI derivative financial instruments	$	(730)	$	(838)	$	(730)	$	3,102