Accounts Receivable Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2014

Accounts Receivable, Net [Abstract]

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

Accounts receivable consisted of the following at December 31, 2014 and 2013 (dollars in thousands):

	2014			2013
Accounts receivable - trade	$	304,087		$	275,380
Accounts receivable - grants from outside parties	32,076			33,003
Accounts receivable - insurance and other third-party claims	26,941			31,643
Total accounts receivable	363,104			340,026
Allowance for doubtful accounts	(5,826		)	(3,755		)
Accounts receivable, net	$	357,278		$	336,271

Schedule of Allowance for Doubtful Accounts [Table Text Block]

Activity in the Company's allowance for doubtful accounts for the years ended December 31, 2014, 2013 and 2012 was as follows (dollars in thousands):

	2014			2013			2012
Balance, beginning of year	$	3,755		$	2,693		$	2,807
Provisions	5,191			2,741			977
Charges	(3,120		)	(1,679		)	(1,091		)
Balance, end of year	$	5,826		$	3,755		$	2,693