Goodwill and other intangible assets (Tables)

3 Months Ended

Mar. 31, 2017

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



Three Months Ended March 31, 2017	Balance at January 1, 2017		Goodwill Acquired During the Year		Balance at March 31, 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



Three Months Ended March 31, 2016	Balance at January 1, 2016		*	Goodwill Acquired During the Year		Balance at March 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			6,323		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:



	March 31, 2017		March 31, 2016		December 31, 2016
	(In thousands)
Customer relationships	$	15,745	$	17,145	$	17,145
Less accumulated amortization	12,910		12,680		13,917
	2,835		4,465		3,228
Noncompete agreements	2,430		2,430		2,430
Less accumulated amortization	1,695		1,548		1,658
	735		882		772
Other	7,086		7,764		7,768
Less accumulated amortization	5,309		5,308		5,843
	1,777		2,456		1,925
Total	$	5,347	$	7,803	$	5,925