Borrowings - Additional Information (Detail) (USD $)					1 Months Ended				1 Months Ended	3 Months Ended		3 Months Ended		0 Months Ended	3 Months Ended			3 Months Ended			1 Months Ended	3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	May 31, 2007 6.125% Senior Notes [Member]	Aug. 31, 2013 3.95% Senior Notes [Member]	May 31, 2007 Fiscal 2007 Senior Notes [Member]	Sep. 30, 2014 Fiscal 2007 Senior Notes [Member]	Jun. 30, 2014 Fiscal 2007 Senior Notes [Member]	Jun. 30, 2009 Fiscal 2007 Senior Notes [Member]	Aug. 31, 2013 Fiscal 2014 Senior Notes [Member]	Sep. 30, 2014 Fiscal 2014 Senior Notes [Member]	Jun. 30, 2014 Fiscal 2014 Senior Notes [Member]	Sep. 30, 2014 Revolving Credit Facility [Member]	Sep. 30, 2013 Revolving Credit Facility [Member]	Aug. 14, 2014 Fiscal 2015 Revolving Credit Facility [Member] Revolving Credit Facility [Member]	Sep. 30, 2014 Fiscal 2015 Revolving Credit Facility [Member] Revolving Credit Facility [Member]	Aug. 14, 2014 Fiscal 2015 Revolving Credit Facility [Member] Revolving Credit Facility [Member]	Jun. 30, 2014 Fiscal 2015 Revolving Credit Facility [Member] Revolving Credit Facility [Member]	Sep. 30, 2014 Fiscal 2015 Revolving Credit Facility [Member] Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member]	Aug. 14, 2014 U.S. Dollar Tranche [Member] Revolving Credit Facility [Member]	Aug. 14, 2014 Multicurrency Tranche [Member] Revolving Credit Facility [Member]	Sep. 30, 2012 Fiscal 2012 Credit Facilities [Member] Revolving Credit Facility [Member]	Sep. 30, 2014 Fiscal 2012 Credit Facilities [Member] Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility maximum borrowing capacity																$ 750,000,000.0			$ 670,000,000.0	$ 80,000,000.0	$ 500,000,000.0
Term														5 years							5 years
Debt Instrument, Basis Spread on Variable Rate																		1.125%
Debt Instrument, Step-Up Basis Spread on Variable Rate																		1.30%
Debt Instrument, Step-Down Basis Spread on Variable Rate																		0.795%
Annual facility fee (as basis points)															0.125%
Debt Instrument, Unused Borrowing Capacity, Fee															100,000
Debt issuance costs														1,900,000
Debt issuance cost expensed																						100,000
Debt issuance cost capitalized												2,300,000										500,000
Senior notes offered			250,000,000	400,000,000
Maturity date					Jun. 01, 2017				Sep. 01, 2020
Interest rate					6.125%				3.95%
Frequency of interest payment, description										Interest on the Fiscal 2014 Senior Notes is payable semi-annually in arrears on March 1st and September 1st each year.
Percentage of Notes issued					99.10%				99.871%
Effective yield to maturity					6.251%				3.971%
Payments of debt issuance costs					1,900,000				4,300,000			1,900,000	0
Debt issuance cost, amortization period					10 years				7 years
Amortization related to the Senior Notes						1,300,000	1,300,000			700,000	600,000
Purchased principal amount of Senior Notes								125,000,000
Unamortized bond discount								1,000,000
Senior Notes, fair value						137,500,000	139,100,000			418,100,000	426,600,000
Outstanding amount of line of credit	$ 0	$ 0