Property and Equipment, Net

12 Months Ended

Dec. 31, 2015

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

Property and Equipment, net

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



December 31,	2015		2014
Equipment and vehicles	$	731,224	$	767,313
Quarry property	178,357		172,081
Land and land improvements	110,294		110,235
Buildings and leasehold improvements	82,871		82,655
Office furniture and equipment	60,821		70,820
Property and equipment	1,163,567		1,203,104
Less: accumulated depreciation and depletion	778,438		793,451
Property and equipment, net	$	385,129	$	409,653

Depreciation and depletion expense primarily included in cost of revenue in our consolidated statements of operations for the years ended December 31, 2015, 2014 and 2013 was $61.0 million, $64.9 million and $62.7 million, respectively. We capitalized interest costs of $0.4 million, $0.7 million and $0.9 million in 2015, 2014 and 2013, respectively, related to certain self-constructed assets, of which $0.4 million, $0.4 million and $0.6 million, respectively, were included in investments in affiliates and the remaining amounts were included in property and equipment on the consolidated balance sheets.

During the year ended December 31, 2014, we recorded an impairment gain of $1.3 million which was related to the sale of non-performing quarry assets. Refer to Note 11 for details.

We have recorded liabilities associated with our legally required obligations to reclaim owned and leased quarry property and related facilities. As of December 31, 2015 and 2014, $2.0 million and $6.5 million, respectively, of our asset retirement obligations are included in accrued expenses and other current liabilities and $24.6 million and $20.9 million, respectively, are included in other long-term liabilities on the consolidated balance sheets.

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



Years Ended December 31,	2015			2014
Beginning balance	$	27,441		$	29,138
Revisions to estimates	213			2,969
Liabilities settled	(2,114		)	(5,678		)
Accretion	1,018			1,012
Ending balance	$	26,558		$	27,441