Certain Balance Sheet Components

6 Months Ended

Jun. 30, 2019

Balance Sheet Related Disclosures [Abstract]

Certain Balance Sheet Components

Certain Balance Sheet Components

A summary of accounts receivable from contracts with customers is as follows:

Accounts receivable, net
In thousands	June 30, 2019		December 31, 2018
Trade receivables (net of allowance of $4,360 and $6,331)	$	426,936	$	416,503
Unbilled receivables	39,430		20,658
Total accounts receivable, net	$	466,366	$	437,161

Allowance for doubtful accounts activity	Three Months Ended June 30,						Six Months Ended June 30,
In thousands	2019			2018			2019			2018
Beginning balance	$	4,046		$	4,774		$	6,331		$	3,957
Provision for doubtful accounts, net	365			334			(1,738		)	1,254
Accounts written-off	(80		)	(247		)	(272		)	(505		)
Effect of change in exchange rates	29			(309		)	39			(154		)
Ending balance	$	4,360		$	4,552		$	4,360		$	4,552

Inventories
In thousands	June 30, 2019		December 31, 2018
Materials	$	127,219	$	133,398
Work in process	10,888		9,744
Finished goods	91,803		77,532
Total inventories	$	229,910	$	220,674

Property, plant, and equipment, net
In thousands	June 30, 2019			December 31, 2018
Machinery and equipment	$	321,155		$	315,974
Computers and software	108,110			104,290
Buildings, furniture, and improvements	148,026			146,071
Land	15,201			14,980
Construction in progress, including purchased equipment	51,100			49,682
Total cost	643,592			630,997
Accumulated depreciation	(415,079		)	(404,446		)
Property, plant, and equipment, net	$	228,513		$	226,551

Depreciation expense	Three Months Ended June 30,				Six Months Ended June 30,
In thousands	2019		2018		2019		2018
Depreciation expense	$	12,594	$	12,908	$	24,978	$	26,240