Preferred and Common Stockholder's Equity - Additional Information (Detail) - USD ($)	Jun. 30, 2015	Mar. 31, 2015	Feb. 28, 2015	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012
Class of Stock [Line Items]
Preferred stock, shares authorized	5,000,000
Preferred stock, par value	$ 0.01
Preferred stock, shares outstanding	0			0	0
Common stock, shares authorized	150,000,000
Common stock, par value	$ 0.01
Common stock, shares issued	68,900,000			73,500,000	80,600,000	82,600,000
Common stock, shares outstanding	68,900,000			73,500,000	80,600,000	82,600,000
Share repurchase program, remaining authorized repurchase amount	$ 155,000,000
Sixth Share Repurchase Program
Class of Stock [Line Items]
Share repurchase program, authorized amount		$ 300,000,000
Seventh Share Repurchase Program
Class of Stock [Line Items]
Share repurchase program, authorized amount			$ 200,000,000