Income Taxes - Deferred Tax Asset Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Movement In Deferred Tax Asset [Roll Forward]
Beginning Balance December 31, 2014	$ 0			$ 902,300
Change in valuation allowance		$ (739,298)	$ (24,781)	(822,465)	$ (63,229)
Ending Balance September 30, 2015		0		0
Other Comprehensive Income (Loss)
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance		(70,000)	$ 6,600	(54,500)	$ (21,300)
Deferred Tax Asset, Changes In Current Period
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance				(143,400)
Deferred Tax Asset, Changes In Current Period | Other Comprehensive Income (Loss)
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance				6,300
Deferred Tax Asset, Changes In Current Period | Income Tax Expense (Benefit)
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance		(41,200)		$ (124,400)
Deferred Tax Asset, Changes In Current Period | Income Tax Expense (Benefit) | Scenario, Forecast
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance	$ (25,300)
Deferred Tax Asset, Changes In Future Periods
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance		(758,900)
Deferred Tax Asset, Changes In Future Periods | Other Comprehensive Income (Loss)
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance		(60,800)
Deferred Tax Asset, Changes In Future Periods | Income Tax Expense (Benefit)
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance		$ (698,100)