Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2019	Oct. 02, 2016	Oct. 01, 2016
Operating Loss Carryforwards [Line Items]
Cancellation of debt income								$ 4,089,000
Decrease in operating loss carryforwards								3,436,000
Gross timing of deferrals								646,300
Operating loss carryforwards	$ 1,300,000	$ 1,300,000
Annual limitation on operating loss use	29,800	29,800
Income tax benefit from cumulative adjustments		48,800
Tax credit carryforwards	61,100	61,100
Change in uncertain tax positions		26,600
Increase (decrease) in valuation allowance			$ 35,700
Tax loss carryforwards	307,615	307,615	271,405
Tax Cuts and Jobs Act of 2017, Income tax expense (benefit)		16,700	(330,900)
Repatriation of foreign earnings		1,500
Cumulative foreign earnings		4,200
Tax Cuts and Jobs Act of 2017, Income tax expense (benefit) related to valuation allowance	(45,000)
Tax Cuts and Jobs Act of 2017, Provisional income tax expense (benefit) related to change in limit on deductible for covered employees		6,100	200
Valuation allowance	530,612	530,612	610,571
Reductions as a result of lapses in the statute of limitations		3,271	0	$ 37,110	$ 37,100
Interest and penalties accrued related to unrecognized tax benefits	300	300	600
Gross unrecognized tax benefits	$ 39,093	$ 39,093	$ 11,383	$ 7,455	$ 38,877
Scenario, forecast
Operating Loss Carryforwards [Line Items]
Gross unrecognized tax benefits						$ 400
Alternative minimum tax credits
Operating Loss Carryforwards [Line Items]
Decrease in tax credit carryforwards								$ 3,000
Tax credit carryforwards							$ 73,300
Capital loss carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards							64,500
Domestic tax authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards							$ 1,384,000