Condensed Consolidating Financial Statements - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 25, 2016	Sep. 25, 2016	Jun. 26, 2016	Mar. 27, 2016	Dec. 27, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 25, 2016	Dec. 27, 2015	Dec. 28, 2014
Condensed Financial Statements, Captions [Line Items]
Service revenues									$ 348.1	$ 354.2	$ 390.8
Product sales									320.6	302.9	372.2
Total revenues	$ 182.1	$ 165.4	$ 168.2	$ 153.0	$ 177.5	$ 161.7	$ 160.8	$ 157.1	668.7	657.1	763.0
Cost of service revenues									255.8	266.5	304.6
Cost of product sales									259.3	228.8	279.0
Total costs									515.1	495.3	583.6
Gross profit	46.6	25.9	45.2	35.9	42.2	40.4	40.9	38.3	153.6	161.8	179.4
Selling, general and administrative expenses									158.3	150.1	155.5
Research and development expenses									13.9	16.2	18.6
Operating income (loss) from continuing operations	4.6	(13.0)	0.0	(10.2)	1.5	1.6	(3.7)	(3.9)	(18.6)	(4.5)	5.3
Other income (expense):
Interest income (expense), net									(34.7)	(36.0)	(39.2)
Gain (loss) on extinguishment of debt									0.2	(3.4)	(39.1)
Other income (expense), net									0.8	(0.7)	1.2
Total other expense, net									(33.7)	(40.1)	(77.1)
Loss from continuing operations before income taxes									(52.3)	(44.6)	(71.8)
Provision (benefit) for income taxes from continuing operations	0.8	1.9	1.8	3.6	(0.3)	(15.3)	2.3	1.9	8.1	(11.4)	3.9
Income (loss) from continuing operations									(60.4)	(33.2)	(75.7)
Income (loss) from discontinued operations									(0.1)	53.0	(2.3)
Equity in net income (loss) of subsidiaries									0.0	0.0	0.0
Net income (loss)	$ (4.3)	$ (23.6)	$ (10.4)	$ (22.2)	$ (4.0)	$ 55.1	$ (15.1)	$ (16.2)	(60.5)	19.8	(78.0)
Comprehensive income (loss)									(60.8)	20.1	(78.9)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Service revenues									0.0	0.0	0.0
Product sales									(7.8)	(15.7)	(8.5)
Total revenues									(7.8)	(15.7)	(8.5)
Cost of service revenues									0.0	0.0	0.0
Cost of product sales									(7.8)	(15.7)	(8.5)
Total costs									(7.8)	(15.7)	(8.5)
Gross profit									0.0	0.0	0.0
Selling, general and administrative expenses									0.0	0.0	0.0
Research and development expenses									0.0	0.0	0.0
Operating income (loss) from continuing operations									0.0	0.0	0.0
Other income (expense):
Interest income (expense), net									0.0	0.0	0.0
Gain (loss) on extinguishment of debt									0.0	0.0	0.0
Other income (expense), net									0.0	0.0	0.0
Total other expense, net									0.0	0.0	0.0
Loss from continuing operations before income taxes									0.0	0.0	0.0
Provision (benefit) for income taxes from continuing operations									0.0	0.0	0.0
Income (loss) from continuing operations									0.0	0.0	0.0
Income (loss) from discontinued operations									0.0	0.0	0.0
Equity in net income (loss) of subsidiaries									12.6	8.3	(35.5)
Net income (loss)									12.6	8.3	(35.5)
Comprehensive income (loss)									12.9	8.2	(34.6)
Parent Company
Condensed Financial Statements, Captions [Line Items]
Service revenues									0.0	0.0	0.0
Product sales									0.0	0.0	0.0
Total revenues									0.0	0.0	0.0
Cost of service revenues									0.0	0.0	0.0
Cost of product sales									0.0	0.0	0.0
Total costs									0.0	0.0	0.0
Gross profit									0.0	0.0	0.0
Selling, general and administrative expenses									6.3	10.1	8.4
Research and development expenses									0.0	0.0	0.0
Operating income (loss) from continuing operations									(6.3)	(10.1)	(8.4)
Other income (expense):
Interest income (expense), net									(34.6)	(35.8)	(39.3)
Gain (loss) on extinguishment of debt									0.2	(3.4)	(39.1)
Other income (expense), net									0.0	0.0	0.0
Total other expense, net									(34.4)	(39.2)	(78.4)
Loss from continuing operations before income taxes									(40.7)	(49.3)	(86.8)
Provision (benefit) for income taxes from continuing operations									(0.1)	(17.8)	0.6
Income (loss) from continuing operations									(40.6)	(31.5)	(87.4)
Income (loss) from discontinued operations									(0.1)	71.8	(14.7)
Equity in net income (loss) of subsidiaries									(19.8)	(20.5)	24.1
Net income (loss)									(60.5)	19.8	(78.0)
Comprehensive income (loss)									(60.8)	20.1	(78.9)
Subsidiary Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues									330.9	339.0	380.8
Product sales									273.8	262.3	326.1
Total revenues									604.7	601.3	706.9
Cost of service revenues									244.0	255.5	297.0
Cost of product sales									225.0	203.1	247.9
Total costs									469.0	458.6	544.9
Gross profit									135.7	142.7	162.0
Selling, general and administrative expenses									142.3	130.8	136.7
Research and development expenses									13.5	15.7	17.4
Operating income (loss) from continuing operations									(20.1)	(3.8)	7.9
Other income (expense):
Interest income (expense), net									(0.1)	(0.1)	0.3
Gain (loss) on extinguishment of debt									0.0	0.0	0.0
Other income (expense), net									0.2	(3.3)	(2.0)
Total other expense, net									0.1	(3.4)	(1.7)
Loss from continuing operations before income taxes									(20.0)	(7.2)	6.2
Provision (benefit) for income taxes from continuing operations									7.0	4.4	2.8
Income (loss) from continuing operations									(27.0)	(11.6)	3.4
Income (loss) from discontinued operations									0.0	(21.1)	9.3
Equity in net income (loss) of subsidiaries									7.2	12.2	11.4
Net income (loss)									(19.8)	(20.5)	24.1
Comprehensive income (loss)									(19.8)	(20.5)	23.6
Non-Guarantors on a Combined Basis
Condensed Financial Statements, Captions [Line Items]
Service revenues									17.2	15.2	10.0
Product sales									54.6	56.3	54.6
Total revenues									71.8	71.5	64.6
Cost of service revenues									11.8	11.0	7.6
Cost of product sales									42.1	41.4	39.6
Total costs									53.9	52.4	47.2
Gross profit									17.9	19.1	17.4
Selling, general and administrative expenses									9.7	9.2	10.4
Research and development expenses									0.4	0.5	1.2
Operating income (loss) from continuing operations									7.8	9.4	5.8
Other income (expense):
Interest income (expense), net									0.0	(0.1)	(0.2)
Gain (loss) on extinguishment of debt									0.0	0.0	0.0
Other income (expense), net									0.6	2.6	3.2
Total other expense, net									0.6	2.5	3.0
Loss from continuing operations before income taxes									8.4	11.9	8.8
Provision (benefit) for income taxes from continuing operations									1.2	2.0	0.5
Income (loss) from continuing operations									7.2	9.9	8.3
Income (loss) from discontinued operations									0.0	2.3	3.1
Equity in net income (loss) of subsidiaries									0.0	0.0	0.0
Net income (loss)									7.2	12.2	11.4
Comprehensive income (loss)									$ 6.9	$ 12.3	$ 11.0