Detail of Certain Balance Sheet Accounts

12 Months Ended

Dec. 31, 2018

DETAIL OF CERTAIN BALANCE SHEET ACCOUNTS:

Activity in Quanta’s allowance for doubtful accounts consisted of the following (in thousands):



	December 31,
	2018			2017
Balance at beginning of year	$	4,465		$	2,752
Charged to bad debt expense (recoveries of bad debt expense)	7,169			87
Deductions for uncollectible receivables written off (recoveries of uncollectible receivables)	(5,795		)	1,626
Balance at end of year	$	5,839		$	4,465

Property and equipment consisted of the following (in thousands):



	Estimated Useful	December 31,
	Lives in Years	2018			2017
Land	N/A	$	61,305		$	48,832
Buildings and leasehold improvements	5-30	208,974			155,628
Operating equipment and vehicles	1-25	1,865,917			1,834,715
Office equipment, furniture and fixtures and information technology systems	3-10	212,769			170,115
Construction work in progress	N/A	19,507			60,587
		2,368,472			2,269,877
Less — Accumulated depreciation and amortization		(1,092,440		)	(981,275		)
Property and equipment, net		$	1,276,032		$	1,288,602

Accounts payable and accrued expenses consisted of the following (in thousands):



	December 31,
	2018		2017
Accounts payable, trade	$	786,546	$	632,931
Accrued compensation and related expenses	279,107		225,193
Accrued insurance, current portion	56,552		64,112
Deferred revenues, current portion	40,083		15,967
Income and franchise taxes payable	13,094		19,635
Other accrued expenses	139,138		99,622
	$	1,314,520	$	1,057,460