AMORTIZING INTANGIBLE ASSETS AND UNFAVORABLE GAS GATHERING CONTRACT (Tables)

6 Months Ended

Jun. 30, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible assets and liabilities subject to amortization

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

	June 30, 2018
	Gross carrying amount		Accumulated amortization			Net
	(In thousands)
Favorable gas gathering contracts	$	24,195	$	(13,128	)	$	11,067
Contract intangibles		278,448		(130,891	)		147,557
Rights-of-way		162,339		(34,298	)		128,041
Total intangible assets	$	464,982	$	(178,317	)	$	286,665
Unfavorable gas gathering contract	$	10,962	$	(10,153	)	$	809

	December 31, 2017
	Gross carrying amount		Accumulated amortization			Net
	(In thousands)
Favorable gas gathering contracts	$	24,195	$	(12,350	)	$	11,845
Contract intangibles		278,448		(117,821	)		160,627
Rights-of-way		159,986		(31,113	)		128,873
Total intangible assets	$	462,629	$	(161,284	)	$	301,345
Unfavorable gas gathering contract	$	10,962	$	(9,074	)	$	1,888

Recognized amortization expense in other revenues and cost and expenses

We recognized amortization expense in other revenues as follows:

	Three months ended June 30,						Six months ended June 30,
	2018			2017			2018			2017
	(In thousands)
Amortization expense – favorable gas gathering contracts	$	(388	)	$	(388	)	$	(777	)	$	(777	)
Amortization expense – unfavorable gas gathering     contract		538			539			1,078			1,079

We recognized amortization expense in costs and expenses as follows:

	Three months ended June 30,				Six months ended June 30,
	2018		2017		2018		2017
	(In thousands)
Amortization expense – contract intangibles	$	6,535	$	8,551	$	13,070	$	17,102
Amortization expense – rights-of-way		1,592		1,530		3,177		3,057

Estimated aggregate annual amortization expected to be recognized

The estimated aggregate annual amortization expected to be recognized for the remainder of 2018 and each of the four succeeding fiscal years follows.

	Intangible assets		Unfavorable gas gathering contract
	(In thousands)
2018	$	17,053	$	809
2019		33,217		—
2020		33,041		—
2021		29,349		—
2022		26,282		—