Subsequent Events (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended										12 Months Ended		0 Months Ended
	Oct. 26, 2011	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Jun. 30, 2012	Jun. 30, 2011	Aug. 10, 2012 Subsequent Event [Member]
Declared a cash dividend, per share		$ 0.075	$ 0.075	$ 0.025	$ 0.025	$ 0.000	$ 0.000	$ 0.000	$ 0.000	$ 0.000	$ 0.000	$ 0.30	$ 0.10	$ 0.15
Common stock repurchased												129,966
Total cost of repurchase of common stock	$ 200.0											$ 4.8