Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014
Total Revenue					$ 123.6				$ 390.5	$ 418.2	$ 514.1
Gross profit (loss)											(41.3)
Impairment of excess reorganization value										137.2
Special charges for workforce reductions					(2.1)				(2.1)	(13.2)
Reorganization items, net					1.5				(426.9)
Provision (benefit) for income taxes					(2.4)				(1.0)	(0.3)
Predecessor [Member]
Total Revenue						$ 120.7	$ 121.2	$ 148.6	390.5
Cost of sales						126.1	117.7	169.5	413.3
Gross profit (loss)						(5.4)	3.5	(20.9)	(22.8)
Advanced technology costs						5.3	18.0	33.3	56.6
Selling, general and administrative						10.4	10.1	11.7	32.2
Amortization of intangible assets						0.0	0.0	0.0	0.0
Impairment of excess reorganization value									0.0
Special charges for workforce reductions						(0.1)	(2.5)	(0.5)	(2.1)
Other (income)						4.8	8.4	26.2	(39.4)
Operating (loss)						(16.4)	(18.7)	(39.2)	(74.3)
Interest expense						4.7	4.7	4.6	14.0
Interest (income)						(0.1)	0.0	(0.4)	(0.5)
Reorganization items, net						(440.0)	4.7	8.4
Provision (benefit) for income taxes						0.1	(0.1)	(1.0)	(1.0)
Net income (loss)						$ 418.9	$ (28.0)	$ (50.8)	$ 340.1		$ 340.1
Net income (loss) per share - basic						$ 85.49	$ (5.71)	$ (10.37)	$ 69.41
Net income (loss) per share - diluted						$ 55.51	$ (5.71)	$ (10.37)	$ 45.93
Successor [Member]
Total Revenue	$ 157.9	$ 29.2	$ 63.3	$ 167.8	123.6					418.2
Cost of sales	75.8	53.6	59.0	160.9	142.1					349.3
Gross profit (loss)	82.1	(24.4)	4.3	6.9	(18.5)					68.9
Advanced technology costs	25.3	1.9	4.0	1.8	4.7					33.0
Selling, general and administrative	10.5	13.5	6.3	12.3	10.2					42.6
Amortization of intangible assets	6.3	1.1	2.0	4.0	4.3					13.4
Impairment of excess reorganization value	137.2	0.0	0.0	0.0	0.0					137.2
Special charges for workforce reductions	(0.1)	(9.8)	(2.9)	(0.6)	(2.1)					(13.2)
Other (income)	0.3	0.3	0.7	0.8	(1.3)					(2.1)
Operating (loss)	(96.8)	(50.4)	(10.2)	(11.0)	(38.5)					(168.4)
Interest expense	5.0	4.8	4.9	4.9	4.9					19.6
Interest (income)	0.0	(0.1)	0.0	(0.2)	(0.2)					(0.3)
Reorganization items, net					1.5
Provision (benefit) for income taxes	0.0	0.0	0.0	(0.3)	(2.4)					(0.3)
Net income (loss)	$ (101.8)	$ (55.1)	$ (15.1)	$ (15.4)	$ (42.3)					$ (187.4)
Net income (loss) per share - basic	$ (11.19)	$ (6.05)	$ (1.68)	$ (1.71)	$ (4.70)					$ (20.82)
Net income (loss) per share - diluted	$ (11.19)	$ (6.05)	$ (1.68)	$ (1.71)	$ (4.70)					$ (20.82)