Receivables and Allowance for Doubtful Receivables (Tables)

12 Months Ended

Dec. 31, 2012

Receivables and Allowance for Doubtful Receivables [Abstract]

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

		2012	2011
Trade	$	148,902	140,533
Employee		703	720
Other		831	574
Total Receivables	$	150,436	141,827

Allowance For Doubtful Accounts Receivable Rollforward [Table Text Block]

			Additions		Deductions
Description		Balance at beginning of year	Charged to costs and expenses	Charged to other accounts	Write-offs net of recoveries	Balance at end of year
December 31, 2012	$	5,796	3,649	(2,261)	3,969	3,215
December 31, 2011	$	9,189	4,294	(29)	7,658	5,796
December 31, 2010	$	7,060	3,085	1,670	2,626	9,189