Goodwill and other intangible assets (Tables)

9 Months Ended

Sep. 30, 2017

The changes in the carrying amount of goodwill were as follows:



Nine Months Ended September 30, 2017	Balance at January 1, 2017		Goodwill Acquired During the Year		Balance at September 30, 2017
	(In thousands)
Natural gas distribution	$	345,736	$	—	$	345,736
Construction materials and contracting	176,290		—		176,290
Construction services	109,765		—		109,765
Total	$	631,791	$	—	$	631,791



Nine Months Ended September 30, 2016	Balance at January 1, 2016		*	Goodwill Acquired During the Year		Balance at September 30, 2016		*
	(In thousands)
Natural gas distribution	$	345,736		$	—	$	345,736
Pipeline and midstream	9,737			—		9,737
Construction materials and contracting	176,290			—		176,290
Construction services	103,441			6,323		109,764
Total	$	635,204		$	6,323	$	641,527

* Balance is presented net of accumulated impairment of $12.3 million at the pipeline and midstream segment, which occurred in prior periods.



Year Ended December 31, 2016	Balance at January 1, 2016		*	Goodwill Acquired During the Year		Held for Sale			Balance at December 31, 2016
	(In thousands)
Natural gas distribution	$	345,736		$	—	$	—		$	345,736
Pipeline and midstream	9,737			—		(9,737		)	—
Construction materials and contracting	176,290			—		—			176,290
Construction services	103,441			6,324		—			109,765
Total	$	635,204		$	6,324	$	(9,737	)	$	631,791

* Balance is presented net of accumulated impairment of $12.3 million at the pipeline and midstream segment, which occurred in prior periods.

Other amortizable intangible assets were as follows:



	September 30, 2017		September 30, 2016		December 31, 2016
	(In thousands)
Customer relationships	$	15,248	$	17,145	$	17,145
Less accumulated amortization	13,176		13,524		13,917
	2,072		3,621		3,228
Noncompete agreements	2,430		2,430		2,430
Less accumulated amortization	1,769		1,622		1,658
	661		808		772
Other	7,020		7,764		7,768
Less accumulated amortization	5,544		5,664		5,843
	1,476		2,100		1,925
Total	$	4,209	$	6,529	$	5,925