Discontinued Operations - Discontinued Operations Related to Securities Clearing Business (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Mar. 31, 2012	Mar. 31, 2012
Discontinued Operations And Disposal Groups [Abstract]
Impairment of assets of discontinued operations	$ 1.0	$ 1.0