Schedule II - Valuation and Qualifying Accounts (Tables)

12 Months Ended

Dec. 31, 2017

Valuation And Qualifying Accounts [Abstract]

Valuation And Qualifying Accounts Disclosure [Table Text Block]

					Additions
			Balance at Beginning of Year		Charged to Costs and Expenses		Charged to Other Accounts		Other Additions (Deductions)		Balance at End of Year
			(in thousands)
Reserves and allowances deducted from asset accounts:
	Deferred Income Tax Valuation Allowance (1)
		Year Ended December 31, 2017	$	99,638	$	―	$	―	$	(47,628)	$	52,010
		Year Ended December 31, 2016	$	118,957	$	―	$	―	$	(19,319)	$	99,638
		Year Ended December 31, 2015	$	7,150	$	111,807	$	―	$	―	$	118,957
	Reserve for Materials and Supplies
		Year Ended December 31, 2017	$	956	$	―	$	―	$	138	$	1,094
		Year Ended December 31, 2016	$	988	$	―	$	―	$	(32)	$	956
		Year Ended December 31, 2015	$	1,101	$	―	$	―	$	(113)	$	988

• See also Note 15 of Notes to Consolidated Financial Statements in Item 8.