Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Gross federal NOL carryforward	$ 536,600
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	23,600
Valuation allowance adjustment	$ 44,200		$ 215,420
unrecognized tax benefits in equity share based payment	18600
Deferred Income Tax Expense (Benefit)	$ 334,787	$ 311,699	223,769
Gross unrecognized tax benefits	21,502	38,992	$ 32,911	$ 173,310
Income tax liabilities	34,860	57,050
Possible decrease in unrecognized tax benefits	17,400
Unrecognized tax benefits, income tax penalties and interest accrued	$ 12,200	$ 17,200
Minimum [Member]
Income Tax Contingency [Line Items]
IncomeTaxNetOperatingLossCarryforwardPeriod	5 years
Operating loss carryforwards, expiration dates	Jan. 01, 2030
Income tax examination, year(s) under examination	2005
Maximum [Member]
Income Tax Contingency [Line Items]
IncomeTaxNetOperatingLossCarryforwardPeriod	20 years
Operating loss carryforwards, expiration dates	Jan. 01, 2032
Income tax examination, year(s) under examination	2016
2016 to 2020 [Member] | Minimum [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration dates	Jan. 01, 2017
2016 to 2020 [Member] | Maximum [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration dates	Jan. 01, 2021
2016 to 2020 [Member] | State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	$ 13,400
2021 to 2025 [Member] | Minimum [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration dates	Jan. 01, 2022
2021 to 2025 [Member] | State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	$ 210,900