Loans Receivable - FDIC Indemnification Asset (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2016	Sep. 30, 2015
FDIC Indemnification Asset [Roll Forward]
Balance at beginning of period	$ 16,275	$ 36,860
Additions/Adjustments	0	(1,795)
Payments received	(2,153)	(720)
Amortization	(773)	(18,588)
Accretion	131	518
Balance at end of period	$ 13,480	$ 16,275