AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT

12 Months Ended

Dec. 31, 2016

Goodwill And Intangible Assets Disclosure [Abstract]

AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT

5. AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT

Details regarding our intangible assets and the unfavorable gas gathering contract (included in other noncurrent liabilities), all of which are subject to amortization, follow.  

	December 31, 2016
	Useful lives (In years)	Gross carrying amount		Accumulated amortization			Net
		(Dollars in thousands)
Favorable gas gathering contracts	18.7	$	24,195	$	(10,795	)	$	13,400
Contract intangibles	12.5	426,464		(146,468		)	279,996
Rights-of-way	26.1	153,015		(24,959		)	128,056
Total intangible assets		$	603,674	$	(182,222	)	$	421,452
Unfavorable gas gathering contract	10.0	$	10,962	$	(6,916	)	$	4,046

	December 31, 2015
	Useful lives (In years)	Gross carrying amount		Accumulated amortization			Net
		(Dollars in thousands)
Favorable gas gathering contracts	18.7	$	24,195	$	(9,534	)	$	14,661
Contract intangibles	12.5	426,464		(111,052		)	315,412
Rights-of-way	26.3	150,143		(18,906		)	131,237
Total intangible assets		$	600,802	$	(139,492	)	$	461,310
Unfavorable gas gathering contract	10.0	$	10,962	$	(6,077	)	$	4,885

During the fourth quarters of 2015 and 2014, we identified a need to evaluate the goodwill associated with certain of our gathering systems (see Note 6). In connection with these evaluations, we also evaluated the related intangible assets associated therewith for impairment and concluded that no impairment was necessary.

We recognized amortization expense in other revenues as follows:

	Year ended December 31,
	2016			2015			2014
	(In thousands)
Amortization expense – favorable gas gathering contracts	$	(1,261	)	$	(1,478	)	$	(1,741	)
Amortization expense – unfavorable gas gathering contract	839			692			797

We recognized amortization expense in costs and expenses as follows:

	Year ended December 31,
	2016		2015		2014
	(In thousands)
Amortization expense – contract intangibles	$	35,416	$	35,339	$	32,554
Amortization expense – rights-of-way	6,053		5,863		5,260

The estimated aggregate annual amortization expected to be recognized as of December 31, 2016 for each of the five succeeding fiscal years follows.

	Intangible assets		Unfavorable gas gathering contract
	(In thousands)
2017	$	41,854	$	2,158
2018	41,323		1,888
2019	41,154		—
2020	43,403		—
2021	41,630		—