Property and Equipment

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Property and Equipment

6. Property and Equipment

Property and equipment consisted of the following at December 31:

(dollars in thousands)	Estimated Useful Life in Years		2018			2017
Land		—	$	8,475		$	7,733
Buildings and improvements		3 to 39		23,228			22,718
Construction equipment		3 to 12		371,941			340,060
Office equipment		3 to 10		11,743			8,964
				415,387			379,475
Less: Accumulated depreciation and amortization				(253,495	)		(231,391	)
			$	161,892		$	148,084

Construction equipment includes assets under capital leases — see additional information provided in Note 12 — Lease Obligations to the Financial Statements.

Depreciation and amortization expense of property and equipment for the years ended December 31, 2018, 2017 and 2016 was $38.1 million, $38.1 million and $38.2 million, respectively.