VPT Loans and Securities - Schedule of VPT Loans (Details) - USD ($) $ in Millions	Sep. 29, 2017	Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Available-for-sale securities	$ 59.8	$ 95.3
Commitment	11.8	1.1
Original CPTC loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Available-for-sale securities	47.4	95.3
Commitment	0.0	1.1
DRTC securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Available-for-sale securities	8.0	0.0
Commitment	0.0	0.0
GPTC securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Available-for-sale securities	4.4	0.0
Commitment	11.8	0.0
Loans Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commitment	2.2	11.4
Notes, Loans and Financing Receivable, Net	112.1	59.2
Loans Receivable | MPTC loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	60.1	40.7
Commitment	0.0	11.4
Loans Receivable | NYPC loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	18.5	18.5
Commitment	0.0	0.0
Loans Receivable | RPTC senior secured debt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Senior secured debt	25.4	0.0
Commitment	0.0	0.0
Loans Receivable | CPTC DIP loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	5.1	0.0
Commitment	2.2	0.0
Loans Receivable | PI loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	3.0	0.0
Commitment	$ 0.0	$ 0.0