11. COMMITMENTS AND CONTINGENCIES

Commitments

The Company leases corporate office space in Houston, Texas and Denver, Colorado. Rent expense was approximately $3.7 million and $3.9 million for the years ended December 31, 2018 and 2017, respectively. Rent expense was approximately $1.4 million for the period of September 10, 2016 through December 31, 2016 and $5.9 million for the period of January 1, 2016 through September 9, 2016.

Approximate future minimum lease payments for subsequent annual periods for all non-cancelable operating leases as of December 31, 2018 are as follows (in thousands):


2019	$	3,792
2020		2,350
2021		1,899
2022		968
2023		999
Thereafter		599
Total	$	10,607

As of December 31, 2018, the Company has the following active drilling rig commitments (in thousands):


2019	$	4,973
2020		—
2021		—
2022		—
2023		—
Thereafter		—
Total	$	4,973

As of December 31, 2018, termination of the Company's active drilling rig commitments would require early termination penalties of $4.7 million, which would be in lieu of paying the remaining active drilling rig commitments of $5.0 million.

As of December 31, 2018, the Company has the following rig termination and stacking fees commitments (in thousands):


2019	$	781
2020		3,000
2021		—
2022		—
2023		—
Thereafter		—
Total	$	3,781

As of December 31, 2018, the Company has the following purchase commitments related to equipment (in thousands):


2019	$	20,233
2020		—
2021		—
2022		—
2023		—
Thereafter		—
Total	$	20,233

The Company has entered into various long-term gathering, transportation and sales contracts with respect to production from the Delaware Basin in West Texas. As of December 31, 2018, the Company had in place three long‑term crude oil contracts and ten long‑term natural gas contracts in this area and the sales prices under these contracts are based on posted market rates. Under the terms of these contracts, the Company has committed a substantial portion of its production from this area for periods ranging from one to twenty years from the date of first production. The sales prices under these contracts are based on posted market rates.

Contingencies

From time to time, the Company may be a plaintiff or defendant in a pending or threatened legal proceeding arising in the normal course of its business. While the outcome and impact of currently pending legal proceedings cannot be determined, the Company’s management and legal counsel believe that the resolution of these proceedings through settlement or adverse judgment will not have a material effect on the Company’s consolidated operating results, financial position or cash flows.