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)	110,612			110,612		110,612
Other comprehensive income (loss), net of tax	(18,361)				(18,361)	(18,361)
Total comprehensive income (loss)						92,251
Balance at Jun. 30, 2015		2,500	901,422	514,225	66,261	1,484,408
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
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
Parent/child asset transfers			(72,179)			(72,179)
Comprehensive income:
Net income (loss)	(1,458,895)			(1,458,895)		(1,458,895)
Other comprehensive income (loss), net of tax	$ 193,745				193,745	193,745
Total comprehensive income (loss)						(1,265,150)
Balance at Jun. 30, 2016		$ 2,500	$ 9,251,198	$ (1,062,065)	$ 239,911	$ 8,431,544