Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Line of Credit Facility [Line Items]
Outstanding borrowings	$ 0	$ 0
Aggregate commitments including borrowings and letters of credit	400
Line of credit facility, initiation date	May 10, 2011
Annual fee percentage	0.125%
Commitment fee percentage	0.20%
Prime Rate
Line of Credit Facility [Line Items]
Addition to LIBOR to determine interest rate	0.75%
Percentage of maximum raise in interest rate over base rate	1.50%
LIBOR
Line of Credit Facility [Line Items]
Percentage of maximum raise in interest rate over base rate	2.50%
Previous Revolving Credit Facility
Line of Credit Facility [Line Items]
Borrowings and letters of credit, maturity date	2012-01
Revolving Credit Facility
Line of Credit Facility [Line Items]
Line Of Credit Facility Potential Maximum Borrowing Capacity	550
Borrowings and letters of credit, maturity date	2016-05
Letter of credit, outstanding	$ 13.2	$ 9.3
Addition to LIBOR to determine interest rate	1.75%