Sterne Agee (Details) - Sterne Agee [Member] $ in Millions	12 Months Ended
	Sep. 30, 2016 USD ($)
Business Acquisition [Line Items]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 8.6
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	0.1
Business Combination, Consideration Transferred	45.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	24.9
Business Combination, Acquired Receivable, Fair Value	151.6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent	5.7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	4.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	136.0
Business Combination, Bargain Purchase, Gain Recognized, Amount	$ 6.2