Property, Plant and Equipment

6 Months Ended

Jun. 30, 2015

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

6.  PROPERTY, PLANT AND EQUIPMENT

A summary of the historical cost of property, plant and equipment is as follows:

thousands	Estimated Useful Life	June 30, 2015		December 31, 2014
Land	n/a	$	3,336	$	2,884
Gathering systems	3 to 47 years	5,527,042		4,972,892
Pipelines and equipment	15 to 45 years	136,303		151,107
Assets under construction	n/a	262,334		483,347
Other	3 to 40 years	19,133		16,420
Total property, plant and equipment		5,948,148		5,626,650
Accumulated depreciation		1,165,607		1,055,207
Net property, plant and equipment		$	4,782,541	$	4,571,443

The cost of property classified as “Assets under construction” is excluded from capitalized costs being depreciated. These amounts represent property that is not yet suitable to be placed into productive service as of the respective balance sheet date.

During 2015, WES recognized impairments of $9.5 million, primarily due to the abandonment of compressors at the MIGC system and the DJ Basin complex. See Note 2for a discussion of WES’s assets held for sale as of June 30, 2015.