The Fair Value Option For Certain Loans - Schedule of Fair Value Option (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of loans	$ 14,198	$ (24,394)	$ 35,253	$ 7,914
Long-term loans and written loan commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of loans	14,197	(24,394)	35,252	7,914
Noninterest Income | Long-term loans and written loan commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of loans	$ 14,197	$ (24,394)	$ 35,252	$ 7,914