Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Retained Loss	Treasury Stock
Beginning Balances at Dec. 31, 2016	$ (2,928,151)	$ 510,063	$ (3,438,165)	$ (49)
Beginning Balances, Shares at Dec. 31, 2016		80,017
Equitization of Holdco Notes	978,230	$ 978,230
Equitization of Holdco Notes, Shares		70,579
Rights Offering, including Backstop	573,774	$ 573,774
Rights Offering, including Backstop, Shares		44,390
Employee stock plan grants, Shares		10
Stock plan grants	26,673	$ 26,673
Stock plan grants, Shares		2,191
Net share settlements	(9,580)		(9,580)
Net share settlements, Shares		(840)
Fair value of employee stock plan grants	27,278	$ 27,278
Net income	177,140		177,140
Ending Balances at Dec. 31, 2017	(1,154,636)	$ 2,116,018	(3,270,605)	(49)
Ending Balances, Shares at Dec. 31, 2017		196,347
Stock plan grants, Shares		1,226
Net share settlements	(2,061)		(2,061)
Net share settlements, Shares		(519)
Fair value of employee stock plan grants	13,173	$ 13,173
Net income	26,933		26,933
Initial adoption of ASC 606	1,765		1,765
Ending Balances at Jun. 30, 2018	$ (1,114,826)	$ 2,129,191	$ (3,243,968)	$ (49)
Ending Balances, Shares at Jun. 30, 2018		197,054