CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 25, 2016	Dec. 27, 2015	Dec. 28, 2014
Income Statement [Abstract]
Service revenues	$ 348.1	$ 354.2	$ 390.8
Product sales	320.6	302.9	372.2
Total revenues	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	153.6	161.8	179.4
Selling, general and administrative expenses	146.3	150.7	153.6
Merger and acquisition related items	1.9	0.1	0.2
Research and development expenses	13.9	16.2	18.6
Unused office space and other restructuring	10.1	(0.7)	1.7
Operating income (loss) from continuing operations	(18.6)	(4.5)	5.3
Other income (expense):
Interest 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	8.1	(11.4)	3.9
Income (loss) from continuing operations	(60.4)	(33.2)	(75.7)
Income (loss) from operations of discontinued component (including gain on disposal of $80.8 million for the year ended December 27, 2015)	(0.1)	75.5	(1.1)
Income tax expense	0.0	22.5	1.2
Income (loss) from discontinued operations	(0.1)	53.0	(2.3)
Net income (loss)	$ (60.5)	$ 19.8	$ (78.0)
Basic income and loss per common share:
Net income (loss) from continuing operations (in dollars per share)	$ (0.99)	$ (0.56)	$ (1.31)
Net income (loss) from discontinued operations (in dollars per share)	0.00	0.90	(0.04)
Net income (loss) per common share (in dollars per share)	(0.99)	0.34	(1.35)
Diluted income and loss per common share:
Net income (loss) from continuing operations (in dollars per share)	(0.99)	(0.56)	(1.31)
Net income (loss) from discontinued operations (in dollars per share)	0.00	0.90	(0.04)
Net income (loss) per common share (in dollars per share)	$ (0.99)	$ 0.34	$ (1.35)
Weighted average common shares outstanding:
Basic (in shares)	61.3	58.7	57.6
Diluted (in shares)	61.3	58.7	57.6
Comprehensive Income (Loss)
Net income (loss)	$ (60.5)	$ 19.8	$ (78.0)
Other comprehensive income (loss):
Change in cumulative translation adjustment	(0.5)	0.1	(0.4)
Postretirement benefit reserve adjustment net of tax expense	0.2	0.2	(0.5)
Other comprehensive income (loss), net of tax	(0.3)	0.3	(0.9)
Comprehensive income (loss)	$ (60.8)	$ 20.1	$ (78.9)