Fixed Assets and Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2016

Fixed assets consisted of the following:



	December 31,
	2016			2015
Crude oil pipelines and natural gas pipelines and related assets	$	2,901,202		$	2,501,821
Machinery and equipment	427,658			414,100
Transportation equipment	17,543			19,025
Marine vessels	863,199			794,508
Land, buildings and improvements	55,712			41,202
Office equipment, furniture and fixtures	9,654			7,540
Construction in progress	440,225			485,575
Other	48,203			46,455
Fixed assets, at cost	4,763,396			4,310,226
Less: Accumulated depreciation	(548,532		)	(378,247		)
Net fixed assets	$	4,214,864		$	3,931,979

A reconciliation of our liability for asset retirement obligations is as follows:



December 31, 2014	$	14,790
AROs arising from our Enterprise acquisition	158,230
AROs from the consolidation of historical interests in CHOPS and SEKCO	1,988
Accretion expense	4,941
Revisions in timing of expected settlement	9,986
Settlements	(1,273		)
December 31, 2015	188,662
AROs arising from the acquisition and consolidation of a previously held equity method investment	20,940
Accretion expense	10,800
Revisions in timing and estimated costs of AROs	(2,254		)
Settlements	(4,422		)
December 31, 2016	$	213,726

With respect to our AROs, the following table presents our forecast of accretion expense for the periods indicated: