Equity and Partners' Capital (Tables)

12 Months Ended

Dec. 31, 2017

Partners' Capital Notes [Abstract]

Partnership Interests Table

The following table summarizes WES’s common, Class C, Series A Preferred and general partner units issued during the years ended December 31, 2017 and 2016:

	WES Common Units	WES Class C Units	WES Series A Preferred Units		WES General Partner Units	Total
Balance at December 31, 2015	128,576,965	11,411,862	—		2,583,068	142,571,895
PIK Class C units	—	946,261	—		—	946,261
Springfield acquisition	2,089,602	—	14,030,611		—	16,120,213
April 2016 Series A units issuance	—	—	7,892,220		—	7,892,220
Long-Term Incentive Plan award vestings	5,403	—	—		—	5,403
Balance at December 31, 2016	130,671,970	12,358,123	21,922,831		2,583,068	167,535,992
PIK Class C units	—	885,760	—		—	885,760
Conversion of Series A Preferred units	21,922,831	—	(21,922,831	)	—	—
Long-Term Incentive Plan award vestings	7,304	—	—		—	7,304
Balance at December 31, 2017	152,602,105	13,243,883	—		2,583,068	168,429,056