Stock Compensation - Estimated Fair Value of Each Option Grant (Detail) (USD $)	3 Months Ended		6 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (based on historical data)	33.90%	30.50%	33.70%	29.70%
Expected life in years	4 years	4 years 9 months	4 years	4 years 9 months
Risk-free interest rate	0.70%	0.83%	0.70%	1.00%
Fair value per award	$ 2.47	$ 1.69	$ 2.43	$ 1.76