Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment and Asset Retirement Obligation [Abstract]

Property and Equipment

Balances of major classes of assets and allowances for depreciation and depletion are included in property and equipment, net in the consolidated balance sheets as follows (in thousands):

December 31,	2017		2016
Equipment and vehicles	$	778,549	$	756,602
Quarry property	182,267		174,839
Land and land improvements	108,830		110,999
Buildings and leasehold improvements	82,601		82,762
Office furniture and equipment	56,894		56,381
Property and equipment	1,209,141		1,181,583
Less: accumulated depreciation and depletion	801,723		774,933
Property and equipment, net	$	407,418	$	406,650

Change in Asset Retirement Obligation

The following is a reconciliation of these asset retirement obligations (in thousands):

Years Ended December 31,	2017			2016
Beginning balance	$	21,936		$	26,558
Revisions to estimates	462			(2,058		)
Liabilities settled	(966		)	(3,806		)
Accretion	1,095			1,242
Ending balance	$	22,527		$	21,936