Valuation and Qualifying Accounts (Note)

12 Months Ended

Dec. 31, 2016

Valuation and Qualifying Accounts [Abstract]

Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]

Valuation and Qualifying Accounts

Accounts receivable balances are stated net of allowance for doubtful accounts. Historically, the Company has not experienced significant write-offs. The Company records allowances for doubtful accounts when it is probable that the accounts receivable balance will not be collected. The following table provides a summary of the allowance for doubtful accounts balances and activity for the years ended December 31, 2016, 2015 and 2014:

	Year Ended December 31,
(in thousands)	2016			2015			2014
Beginning balance-allowance for doubtful accounts	$	19,140		$	20,546		$	22,079
Additions-charged to expense	6,556			8,209			11,156
Amounts written off	(6,839		)	(7,862		)	(10,573		)
Other (primarily changes in foreign currency exchange rates)	(488		)	(1,753		)	(2,116		)
Ending balance-allowance for doubtful accounts	$	18,369		$	19,140		$	20,546