Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Property, plant and equipment consists of the following (in thousands):



	December 31,
	2015			2014
Oil and natural gas properties
Proved(1)	$	12,529,681		$	11,707,147
Unproved	363,149			290,596
Total oil and natural gas properties	12,892,830			11,997,743
Less accumulated depreciation, depletion and impairment	(11,149,888		)	(6,359,149		)
Net oil and natural gas properties capitalized costs	1,742,942			5,638,594
Land	14,260			16,300
Non-oil and natural gas equipment(2)	373,687			602,392
Buildings and structures(3)	227,673			263,191
Total	615,620			881,883
Less accumulated depreciation and amortization	(123,860		)	(305,420		)
Other property, plant and equipment, net	491,760			576,463
Total property, plant and equipment, net	$	2,234,702		$	6,215,057

____________________


(1)	Includes cumulative capitalized interest of approximately $48.9 million and $38.1 million at December 31, 2015 and 2014, respectively.


(2)	Includes cumulative capitalized interest of approximately $4.3 million at both December 31, 2015 and 2014.


(3)	Includes cumulative capitalized interest of approximately $20.4 million and $17.1 million at December 31, 2015 and 2014, respectively.

Capitalized Costs of Unproved Properties Excluded from Amortization

The following table summarizes the costs, by year incurred, related to unproved properties and pipe inventory, which were excluded from oil and natural gas properties subject to amortization at December 31, 2015 (in thousands):



			Year Cost Incurred
	Total		2015		2014		2013		2012 and Prior
Property acquisition	$	362,803	$	197,849	$	70,304	$	14,011	$	80,639
Exploration(1)	34,988		10,698		6,263		17,688		339
Total costs incurred	$	397,791	$	208,547	$	76,567	$	31,699	$	80,978

____________________


(1)	Includes $34.7 million of pipe inventory costs incurred ($10.5 million in 2015, $6.2 million in 2014 and $18.0 million in 2013 and prior years).