Income Taxes - Summary of Changes In Tax Provisions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement In Deferred Tax Asset [Roll Forward]
Balance at December 31, 2014	$ 902,289	$ 1,004,200
Change in valuation allowance	161,158	88,833	$ (20,935)
Balance at December 31, 2015	0	$ 902,289	$ 1,004,200
Deferred Tax Asset, Changes In Current Period
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance	(154,800)
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	(161,100)
Deferred Tax Asset, Changes In Future Periods
Movement In Deferred Tax Asset [Roll Forward]
Change in valuation allowance	(747,500)
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	$ (686,700)