CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - $ / shares	Sep. 30, 2015	Sep. 30, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	350,000,000	350,000,000
Common stock, shares issued (in shares)	149,283,682	146,103,658
Treasury stock, shares (in shares)	6,364,706	4,900,266