Property and Equipment

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

The following table summarizes our property and equipment as of the dates presented:


	December 31,
	2020		2019
Oil and gas properties:
Proved	$	1,545,910	$	1,409,219
Unproved	49,935		53,200
Total oil and gas properties	1,595,845		1,462,419
Other property and equipment	27,746		25,915
Total property and equipment	1,623,591		1,488,334
Accumulated depreciation, depletion and amortization	(900,042)		(367,909)
	$	723,549	$	1,120,425

Unproved property costs of $49.9 million and $53.2 million have been excluded from amortization as of December 31, 2020 and December 31, 2019, respectively. An additional $1.2 million of costs, associated with wells in-progress for which we had not previously recognized any proved undeveloped reserves, were excluded from amortization as of December 31, 2020. The total costs not subject to amortization as of December 31, 2020 were incurred in the following periods: $2.2 million in 2020, $1.6 million in 2019, $2.0 million in 2018 and $44.2 million prior to 2018 as well as $1.1 million of capitalized interest applied thereto. We transferred $8.3 million and $16.8 million of undeveloped leasehold costs, including capitalized interest, associated with proved undeveloped reserves, acreage unlikely to be drilled or expiring acreage, from unproved properties to the full cost pool during the years ended December 31, 2020 and 2019, respectively. We capitalized internal costs of $2.1 million, $4.1 million and $3.7 million and interest of $2.7 million, $4.1 million and $9.1 million during the year ended December 31, 2020, 2019 and 2018 respectively, in accordance with our accounting policies. Average DD&A per BOE of proved oil and gas properties was $15.83, $17.25 and $16.11 for the years ended December 31, 2020, 2019 and 2018, respectively.

As of December 31, 2020, the carrying value of our proved oil and gas properties exceeded the limit determined by the Ceiling Test by $120.3 million. Accordingly, we recorded an impairment of our oil and gas properties by this amount for the three months ended December 31, 2020, and when combined with the $271.5 million record in the first nine months of 2020, $391.8 million for the year ended December 31, 2020. Because the Ceiling Test utilizes commodity prices based on a trailing twelve month average, as of December 31, 2020 it does not fully reflect the substantial decline in commodity prices that accelerated early in the second quarter of 2020 due to the economic impact of the COVID-19 pandemic and the ongoing disruption in global energy markets. Accordingly, we may incur an additional impairment during the first quarter of 2021.