Valuation and Qualifying Accounts (Tables)

12 Months Ended

Dec. 31, 2016

Valuation and Qualifying Accounts [Abstract]

Summary of Valuation Allowance [Table Text Block]

Description	Balance at Beginning of Period		Other Adjustments			Additions Charged to Costs and Expenses		Balance at End of Period, Noncurrent
	(in thousands)
Year ended December 31, 2016:
Deferred tax assets valuation allowance	$	235,339	$	(12,419	)	$	26,640	$	249,560
Year ended December 31, 2015:
Deferred tax assets valuation allowance	$	257,728	$	(62,791	)	$	40,402	$	235,339
Year ended December 31, 2014:
Deferred tax assets valuation allowance	$	162,588	$	(4,913	)	$	100,053	$	257,728