Goodwill and other intangible assets (Tables)

3 Months Ended

Mar. 31, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Changes in the carrying amount of goodwill

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

Three Months Ended March 31, 2014	Balance as of January 1, 2014*		Goodwill Acquired During the Year		Balance as of March 31, 2014*
	(In thousands)
Natural gas distribution	$	345,736	$	—	$	345,736
Pipeline and energy services	9,737		—		9,737
Construction materials and contracting	176,290		—		176,290
Construction services	104,276		—		104,276
Total	$	636,039	$	—	$	636,039

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

Three Months Ended March 31, 2013	Balance as of January 1, 2013*		Goodwill Acquired During the Year		Balance as of March 31, 2013*
	(In thousands)
Natural gas distribution	$	345,736	$	—	$	345,736
Pipeline and energy services	9,737		—		9,737
Construction materials and contracting	176,290		—		176,290
Construction services	104,276		—		104,276
Total	$	636,039	$	—	$	636,039

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

Year Ended December 31, 2013	Balance as of January 1, 2013*		Goodwill Acquired During the Year		Balance as of December 31, 2013*
	(In thousands)
Natural gas distribution	$	345,736	$	—	$	345,736
Pipeline and energy services	9,737		—		9,737
Construction materials and contracting	176,290		—		176,290
Construction services	104,276		—		104,276
Total	$	636,039	$	—	$	636,039

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

Other amortizable intangible assets

Other amortizable intangible assets were as follows:

	March 31, 2014			March 31, 2013			December 31, 2013
	(In thousands)
Customer relationships	$	21,310		$	21,310		$	21,310
Accumulated amortization	(14,230		)	(12,211		)	(13,726		)
	7,080			9,099			7,584
Noncompete agreements	5,580			7,236			6,186
Accumulated amortization	(4,335		)	(5,439		)	(4,840		)
	1,245			1,797			1,346
Other	10,920			10,979			10,995
Accumulated amortization	(6,949		)	(5,557		)	(6,826		)
	3,971			5,422			4,169
Total	$	12,296		$	16,318		$	13,099