Loans Receivable - FDIC Indemnification Asset (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016
FDIC Indemnification Asset [Roll Forward]
Balance at beginning of period	$ 12,769	$ 16,275
Payments made (received)	242	(1,730)
Amortization	(387)	(2,012)
Accretion	50	236
Balance at end of period	$ 12,674	$ 12,769