Property, Plant And Equipment

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Property, Plant And Equipment

Property, Plant and Equipment and Other Intangibles

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

					Estimated  Depreciable Lives
	December 31,
	2014		2015
Construction work-in-progress	$	314,349	$	476,662
Land and rights-of-way	243,576		275,277
Buildings	81,657		88,641		10 to 56 years
Storage tanks	1,538,891		1,684,430		10 to 40 years
Pipeline and station equipment	2,083,204		2,249,067		10 to 69 years
Processing equipment	1,103,454		1,217,492		3 to 56 years
Other	168,804		175,197		3 to 48 years
Property, Plant and Equipment, Gross	$	5,533,935	$	6,166,766

Other includes total interest capitalized on construction in progress as of December 31, 2014 and 2015 of $35.8 million and $31.4 million, respectively. Depreciation expense for the years ended December 31, 2013, 2014 and 2015 was $136.4 million, $159.0 million and $164.1 million, respectively.

We amortize other intangible assets over their estimated useful lives of 5 years up to 25 years. The weighted average asset life of our other intangible assets at December 31, 2015 was approximately 6 years. We adjust the useful lives of our other intangible assets if events or circumstances indicate there has been a change in the remaining useful lives. We eliminate from our balance sheets the gross carrying amount and the related accumulated amortization for any fully amortized intangibles in the year they are fully amortized.  During the years ended December 31, 2013, 2014 and 2015 amortization of other intangible assets was $6.0 million, $2.7 million and $2.7 million, respectively.  No material impairments of intangible assets were recorded during these same annual periods.