Borrowings - Additional Information (Details) - USD ($)			1 Months Ended			3 Months Ended		6 Months Ended
	Feb. 06, 2017	Aug. 14, 2014	Jun. 30, 2016	Aug. 31, 2014	Aug. 31, 2013	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2018
Debt Instrument [Line Items]
Principal amount outstanding at December 31, 2018						$ 1,200,000,000		$ 1,200,000,000
Unused available capacity						700,000,000		700,000,000
Outstanding borrowings						1,194,100,000		1,194,100,000		$ 1,053,400,000
Fair value, senior notes						1,175,200,000		1,175,200,000
Outstanding amount of line of credit						0		0		0
Revolving Credit Facility
Debt Instrument [Line Items]
Debt issuance costs remaining to be amortized, revolving credit facilities						1,800,000		1,800,000
Fiscal 2015 Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity		$ 750,000,000.0
Term				5 years
Debt issuance costs remaining to be amortized, revolving credit facilities						500,000		500,000
Fiscal 2012 Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Debt issuance costs remaining to be amortized, revolving credit facilities						100,000		100,000
Fiscal 2014 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Principal amount, senior notes					$ 400,000,000.0
Interest rate, senior notes					3.95%
Percentage of principal amount					99.871%
Effective interest rate, senior notes					3.971%
Debt issuance costs incurred, senior notes					$ 4,300,000
Debt issuance cost, amortization period, senior notes					7 years
Debt issuance costs remaining to be amortized, senior notes						1,000,000		1,000,000		1,300,000
Fiscal 2014 Senior Notes | Senior Notes | Level 1
Debt Instrument [Line Items]
Fair value, senior notes										405,800,000
Fiscal 2014 Senior Notes | Senior Notes | Long-term debt
Debt Instrument [Line Items]
Principal amount outstanding at December 31, 2018						400,000,000		400,000,000
Outstanding borrowings						398,900,000		398,900,000		398,500,000
Fair value, senior notes						$ 402,900,000		402,900,000
Fiscal 2017 Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity	$ 1,000,000,000.0
Term	5 years
Tranche borrowing period						360 days
Annual facility fee (as basis points)		0.125%
Annual facility fee						$ 300,000	$ 300,000	600,000	$ 600,000
Debt issuance costs, total incurred	$ 1,800,000
Fiscal 2017 Revolving Credit Facility | Revolving Credit Facility | Long-term debt
Debt Instrument [Line Items]
Principal amount outstanding at December 31, 2018						300,000,000		300,000,000
Unused available capacity						700,000,000		700,000,000
Outstanding borrowings						300,000,000		300,000,000		160,000,000
Fair value, senior notes						$ 300,000,000		$ 300,000,000
Fiscal 2017 Revolving Credit Facility U.S. Dollar Tranche | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity	900,000,000.0
Fiscal 2017 Revolving Credit Facility Multicurrency Tranche | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity	$ 100,000,000.0
Revolving Credit Facilities | Revolving Credit Facility
Debt Instrument [Line Items]
Weighted-average interest rate, fiscal 2017 revolving credit facility						3.24%	2.25%	3.13%	2.23%
Fiscal 2016 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Principal amount, senior notes			$ 500,000,000.0
Interest rate, senior notes			3.40%
Percentage of principal amount			99.589%
Effective interest rate, senior notes			3.449%
Debt issuance costs incurred, senior notes			$ 4,500,000
Debt issuance cost, amortization period, senior notes			10 years
Debt issuance costs remaining to be amortized, senior notes						$ 3,200,000		$ 3,200,000		3,500,000
Fiscal 2016 Senior Notes | Senior Notes | Level 1
Debt Instrument [Line Items]
Fair value, senior notes										474,400,000
Fiscal 2016 Senior Notes | Senior Notes | Long-term debt
Debt Instrument [Line Items]
Principal amount outstanding at December 31, 2018						500,000,000		500,000,000
Outstanding borrowings						495,200,000		495,200,000		$ 494,800,000
Fair value, senior notes						$ 472,300,000		$ 472,300,000
London Interbank Offered Rate (LIBOR) | Fiscal 2017 Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Variable interest rate		1.00%