Goodwill and other intangible assets (Tables)

6 Months Ended

Jun. 30, 2012

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, 2012	Balance as of January 1, 2012*		Goodwill Acquired During the Year**		Balance as of June 30, 2012*
	(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	103,168		458		103,626
Total	$	634,931	$	458	$	635,389

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

** Includes a purchase price adjustment that was not material related to an acquisition in a prior period.

Six Months Ended June 30, 2011	Balance as of January 1, 2011*		Goodwill Acquired During the Year**		Balance as of June 30, 2011*
	(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	102,870		298		103,168
Total	$	634,633	$	298	$	634,931

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

** Includes a purchase price adjustment that was not material related to an acquisition in a prior period.

Year Ended December 31, 2011	Balance as of January 1, 2011*		Goodwill Acquired During the Year**		Balance as of December 31, 2011*
	(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	102,870		298		103,168
Total	$	634,633	$	298	$	634,931

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

** Includes a purchase price adjustment that was not material related to an acquisition in a prior period.

Other amortizable intangible assets

Other amortizable intangible assets were as follows:

	June 30, 2012			June 30, 2011			December 31, 2011
	(In thousands)
Customer relationships	$	21,010		$	21,702		$	21,702
Accumulated amortization	(10,690		)	(9,395		)	(10,392		)
	10,320			12,307			11,310
Noncompete agreements	7,086			7,685			7,685
Accumulated amortization	(5,057		)	(5,062		)	(5,371		)
	2,029			2,623			2,314
Other	10,978			12,899			11,442
Accumulated amortization	(4,671		)	(4,492		)	(4,223		)
	6,307			8,407			7,219
Total	$	18,656		$	23,337		$	20,843