Schedule II - Valuation And Qualifying Accounts And Reserves Valuation and Qualifying Accounts and Reserves (Tables)

12 Months Ended

Dec. 31, 2018

Valuation and Qualifying Accounts [Abstract]

Summary of Valuation Allowance [Table Text Block]

Allowance for Doubtful Accounts: 

Description	Balance at Beginning of Period		Additions Charged to Costs & Expenses		Deductions & Net Write-Offs		Balance at End of Period
	(In thousands)
Year ended December 31, 2018	$	2,450	$	81	$	—	$	2,531
Year ended December 31, 2017	$	3,773	$	348	$	(1,671)	$	2,450
Year ended December 31, 2016	$	5,199	$	785	$	(2,211)	$	3,773