Goodwill and other intangible assets (Tables)

6 Months Ended

Jun. 30, 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:

Six Months Ended June 30, 2014	Balance as of January 1, 2014*		Goodwill Acquired During the Year		Balance as of June 30, 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.

Six Months Ended June 30, 2013	Balance as of January 1, 2013*		Goodwill Acquired During the Year		Balance as of June 30, 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:

	June 30, 2014			June 30, 2013			December 31, 2013
	(In thousands)
Customer relationships	$	21,310		$	21,310		$	21,310
Accumulated amortization	(14,734		)	(12,715		)	(13,726		)
	6,576			8,595			7,584
Noncompete agreements	5,080			6,186			6,186
Accumulated amortization	(3,936		)	(4,557		)	(4,840		)
	1,144			1,629			1,346
Other	10,921			10,979			10,995
Accumulated amortization	(7,375		)	(5,891		)	(6,826		)
	3,546			5,088			4,169
Total	$	11,266		$	15,312		$	13,099