Intangible Assets, Net (Notes)

3 Months Ended

Mar. 31, 2017

Finite-Lived Intangible Assets, Net [Abstract]

Intangible Assets Disclosure [Text Block]

7. Intangible Assets, Net

A summary of intangible assets, net, is presented in the table below:

	March 31, 2017							December 31, 2016							Weighted-Average Amortization Period (Years)
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
	(In thousands)
Customer relationships	$	7,172	$	(4,367	)	$	2,805	$	7,172	$	(4,234	)	$	2,938	5.3
Pipeline rights-of-way	6,596		(3,100		)	3,496		6,527		(2,950		)	3,577		5.3
Intangible assets, net	$	13,768	$	(7,467	)	$	6,301	$	13,699	$	(7,184	)	$	6,515

Intangible asset amortization expense was $0.3 million for the three months ended March 31, 2017 and March 31, 2016, based upon estimates of useful lives ranging from 1 to 35 years.

Estimated amortization expense for the indicated periods is as follows (in thousands):

Remainder of 2017	$	820
2018	1,094
2019	1,094
2020	799
2021	646
2022	533