DETAILS OF SELECTED BALANCE SHEET ACCOUNTS

Additional information regarding selected balance sheet accounts at December 31, 2019 and 2018 is presented below (in thousands):



	December 31, 2019			December 31, 2018
Accounts receivable, net:
Trade	$	76,370		$	48,875
Unbilled revenue	23,041			21,169
Other	335			555
Total accounts receivable	99,746			70,599
Allowance for doubtful accounts	(253		)	(376		)
Total accounts receivable, net	$	99,493		$	70,223



	December 31, 2019		December 31, 2018
Inventories:
Finished goods and purchased products	$	3,982	$	2,461
Work in process	813		945
Raw materials	1,082		907
Total inventories	$	5,877	$	4,313

During the fourth quarter of 2017, we recorded a $0.5 million write-down of inventory at our modular construction and manufacturing plant in Canada, which is included in Service and other costs in our accompanying consolidated statements of operations.



	Estimated Useful Life (in years)	December 31, 2019			December 31, 2018
Property, plant and equipment, net:
Land		$	43,147		$	46,805
Accommodations assets	3-15	1,696,425			1,650,758
Buildings and leasehold improvements	7-20	26,108			25,168
Machinery and equipment	4-15	12,060			10,693
Office furniture and equipment	3-7	58,005			54,459
Vehicles	3-5	14,604			14,589
Construction in progress		4,286			7,119
Total property, plant and equipment		1,854,635			1,809,591
Accumulated depreciation		(1,264,326		)	(1,150,686		)
Total property, plant and equipment, net		$	590,309		$	658,905



	December 31, 2019		December 31, 2018
Accrued liabilities:
Accrued compensation	$	17,169	$	13,545
Accrued taxes, other than income taxes	3,152		2,177
Other	1,434		234
Total accrued liabilities	$	21,755	$	15,956