Unaudited Interim Statements of Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings / (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Total Equity
Balance at Dec. 31, 2014		$ 2,500	$ 901,422	$ 673,613	$ 84,622	$ 1,662,157
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Contributed capital	$ 0
Distribution to parent				(270,000)		(270,000)
Comprehensive income:
Net income (loss)	5,786			5,786		5,786
Other comprehensive income (loss), net of tax	(22,072)				(22,072)	(22,072)
Total comprehensive income (loss)						(16,286)
Balance at Sep. 30, 2015		2,500	901,422	409,399	62,550	1,375,871
Balance at Dec. 31, 2014		2,500	901,422	673,613	84,622	1,662,157
Balance at Dec. 31, 2015		2,500	901,422	396,830	46,166	1,346,918
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Contributed capital	781,125		8,421,955			8,421,955
Assets purchased/transferred from/to affiliates			(119,546)	32,014		(87,532)
Comprehensive income:
Net income (loss)	(889,246)			(889,246)		(889,246)
Other comprehensive income (loss), net of tax	$ 179,716				179,716	179,716
Total comprehensive income (loss)						(709,530)
Balance at Sep. 30, 2016		$ 2,500	$ 9,203,831	$ (460,402)	$ 225,882	$ 8,971,811