Derivatives - Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 30, 2019	Mar. 31, 2018	Mar. 30, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Changes in value of hedged interest rate caps, net of tax of $0.3 and $0.8 for the three and six months ended March 30, 2019 and $0.3 and $(4.6) for the three and six months ended March 31, 2018:	$ (1.5)	$ 0.7	$ (5.4)	$ (3.6)
Interest rate cap agreements
Derivative Instruments, Gain (Loss) [Line Items]
Changes in value of hedged interest rate caps, net of tax of $0.3 and $0.8 for the three and six months ended March 30, 2019 and $0.3 and $(4.6) for the three and six months ended March 31, 2018:	$ (1.5)	$ 0.7	$ (5.4)	$ (3.6)

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109978405&loc=d3e80720-113993

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

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Period Type:	duration