Property and Equipment

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

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



	December 31,
	2019			2018
Oil and gas properties:
Proved	$	1,409,219		$	1,037,993
Unproved	53,200			63,484
Total oil and gas properties	1,462,419			1,101,477
Other property and equipment	25,915			20,383
Total property and equipment	1,488,334			1,121,860
Accumulated depreciation, depletion and amortization	(367,909		)	(193,866		)
	$	1,120,425		$	927,994

Unproved property costs of $53.2 million and $63.5 million have been excluded from amortization as of December 31, 2019 and December 31, 2018, respectively. An additional $0.3 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, 2018. The total costs not subject to amortization as of December 31, 2019 were incurred in the following periods: $1.3 million in 2019, $6.1 million in 2018, $43.1 million in 2017 and the remaining $2.7 million in 2016. We transferred $16.8 million and $82.8 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, 2019 and 2018, respectively. We capitalized internal costs of $4.1 million, $3.7 million and $2.4 million and interest of $4.1 million, $9.1 million and $2.7 million during the year ended December 31, 2019, 2018 and 2017 respectively, in accordance with our accounting policies. Average DD&A per barrel of oil equivalent of proved oil and gas properties was $17.25, $16.11 and $12.87 for the years ended December 31, 2019, 2018 and 2017, respectively.