Accounts Receivable Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2018

Schedule of Accounts, Notes, Loans and Financing Receivable

Accounts receivable consisted of the following at December 31, 2018 and 2017 (dollars in thousands):



	2018			2017
Accounts receivable - trade	$	397,255		$	401,723
Accounts receivable - grants from outside parties	19,376			17,734
Accounts receivable - insurance and other third-party claims	19,729			10,753
Total accounts receivable	436,360			430,210
Allowance for doubtful accounts	(10,055		)	(13,505		)
Accounts receivable, net	$	426,305		$	416,705

Schedule of Allowance for Doubtful Accounts

Activity in the Company's allowance for doubtful accounts for the years ended December 31, 2018, 2017 and 2016 was as follows (dollars in thousands):



	2018			2017			2016
Balance, beginning of year	$	13,505		$	12,070		$	6,213
Provisions	6,681			7,752			19,655
Charges	(10,131		)	(6,317		)	(13,798		)
Balance, end of year	$	10,055		$	13,505		$	12,070

Grant amortization offset to depreciation expense [Table Text Block]

The following table sets forth the offset to depreciation expense from the amortization of deferred grants recorded by the Company during the years ended December 31, 2018, 2017 and 2016 (dollars in thousands):



	2018		2017		2016
Amortization of deferred grants	$	12,008	$	12,356	$	13,465