Fair Value of Financial Instruments and Concentrations of Credit Risk (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of accounts receivable

Accounts receivable consisted of the following at December 31:

(In thousands)	2017			2016
Gross trade receivables	$	256,851		$	162,569
Allowance for doubtful accounts	(9,457		)	(8,849		)
Net trade receivables	247,394			153,720
Income tax receivables	6,905			39,944
Other receivables	11,567			20,643
Total receivables, net	$	265,866		$	214,307

Schedule of allowance for doubtful accounts

Changes in this allowance for 2017, 2016 and 2015 was as follows:

(In thousands)	2017			2016			2015
Balance at beginning of year	$	8,849		$	7,189		$	5,458
Provision for uncollectible accounts	1,481			2,416			1,886
Write-offs, net of recoveries	(873		)	(756		)	(155		)
Balance at end of year	$	9,457		$	8,849		$	7,189