Borrowings - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended		1 Months Ended	9 Months Ended	1 Months Ended	3 Months Ended		9 Months Ended		1 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012	Jun. 30, 2012	Sep. 22, 2011 Senior unsecured credit facility [Member]	Sep. 22, 2011 Five-year term loan facility [Member]	Mar. 31, 2013 Five-year term loan facility [Member]	Sep. 22, 2011 Five-year revolving credit facility [Member] BasisPoint	Mar. 31, 2013 Fiscal 2012 Term Loan [Member]	Mar. 31, 2012 Fiscal 2012 Term Loan [Member]	Mar. 31, 2013 Fiscal 2012 Term Loan [Member]	Mar. 31, 2012 Fiscal 2012 Term Loan [Member]	Sep. 22, 2011 Fiscal 2012 Credit Facilities [Member]	Mar. 31, 2013 Fiscal 2012 Credit Facilities [Member]	Mar. 31, 2012 Fiscal 2012 Credit Facilities [Member]
Line Of Credit Facility Covenant Compliance [Line Items]
Long-term debt, Total Capacity	$ 524.5		$ 524.5		$ 524.4	$ 990.0	$ 490.0		$ 500.0
Interest at LIBOR plus basis points							1.25%		1.25%
Annual facility fee (as basis points)									15
Annual facility fee, Total	0.2	0.2	0.6	0.4
Debt issuance costs														3.0
Debt issuance cost expensed														0.1
Debt issuance cost capitalized														2.9
Accumulated amortization of debt issuance cost															0.9	0.3
Minimum principal repayments on the loan								12.3
Total repayment before the balance of the loan becomes due in September 2016								171.5
Repayment of revolving credit facility					90.0
Credit facility maximum borrowing capacity					490.0
First payment due on the loan								Mar. 31, 2013
Final payment due on the loan								2016-06-30
Repayment of short-term borrowings	$ 400.0			$ 400.0
Weighted-average interest rate										1.46%	1.52%	1.47%	1.42%