Condensed Consolidated Balance Sheet Parentheticals (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2012	Sep. 30, 2011
Assets
Cash, securities - fair value	$ 74.7	$ 22.7
Dep and rec -exch clear org - fair value	1,163.0	1,408.2
Dep and rec -b/d - fair value	0.9	16.2
Accounts pay and other accrued - fair value	$ 23.3	$ 22.3
Preferred stock - par value	$ 0.01	$ 0.01
Preferred stock - authorized	1,000,000	1,000,000
Preferred stock - issued	0	0
Preferred stock - outstanding	0	0
Common stock - par value	$ 0.01	$ 0.01
Common stock - authorized	30,000,000	30,000,000
Common stock - issued	19,081,545	18,653,964
Common stock - outstanding	19,069,988	18,642,407
Treasury stock - shares	11,557	11,557