Derivatives and Hedging Activities (Tables)

9 Months Ended

Jun. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Fair Value and Balance Sheet Classification

Although management is not aware of any factors that would materially affect the estimated fair value amounts presented below, such amounts have not been comprehensively revalued for purposes of these financial statements since the dates shown, and therefore, estimates of fair value subsequent to those dates may differ significantly from the amounts presented below.

		June 30, 2018				September 30, 2017
	Level in Fair Value Hierarchy	Carrying Amount		Estimated Fair Value		Carrying Amount		Estimated Fair Value
		($ in thousands)
Financial assets
Cash and cash equivalents	1	$	345,919	$	345,919	$	313,070	$	313,070
Available-for-sale securities
Equity securities	1	491		491		522		522
U.S. government and agency securities	2	216,009		216,009		211,077		211,077
Municipal bonds	2	22,755		22,755		26,624		26,624
Corporate debt securities	2	184,232		184,232		185,298		185,298
Mortgage-backed securities
Agency pass-through certificates	2	828,449		828,449		834,297		834,297
Commercial MBS	2	3,465		3,465		8,391		8,391
Total available-for-sale securities		1,255,401		1,255,401		1,266,209		1,266,209
Held-to-maturity securities
Mortgage-backed securities
Agency pass-through certificates	2	1,655,450		1,595,034		1,646,856		1,635,913
Commercial MBS	2	15,000		15,000		—		—
Total held-to-maturity securities		1,670,450		1,610,034		1,646,856		1,635,913
Loans receivable	3	11,325,971		11,492,022		10,882,622		11,247,586
FDIC indemnification asset	3	—		—		8,968		8,564
FHLB and FRB stock	2	128,790		128,790		122,990		122,990
Other assets - interest rate contracts	2	10,141		10,141		1,139		1,139
Other assets - commercial loan hedges	2	3,005		3,005		—		—
Other assets - borrowings hedges	2	19,193		19,193		—		—
Financial liabilities
Customer accounts	2	11,287,473		10,924,562		10,835,008		10,411,686
FHLB advances	2	2,370,000		2,365,478		2,225,000		2,266,791
Other liabilities - interest rate contracts	2	10,141		10,141		1,139		1,139
Other liabilities - commercial loan hedges	2	—		—		174		174
Other liabilities - borrowings hedges	2	—		—		1,693		1,693

The following table presents the fair value and balance sheet classification of derivatives at June 30, 2018 and September 30, 2017:

	Asset Derivatives						Liability Derivatives
	June 30, 2018			September 30, 2017			June 30, 2018			September 30, 2017
	Balance Sheet			Balance Sheet			Balance Sheet			Balance Sheet
	Location	Fair Value		Location	Fair Value		Location	Fair Value		Location	Fair Value
	(In thousands)
Interest rate contracts	Other assets	$	10,141	Other assets	$	1,139	Other liabilities	$	10,141	Other liabilities	$	1,139
Commercial loan hedges	Other assets	3,005		Other assets	—		Other liabilities	—		Other liabilities	174
Borrowings hedges	Other assets	19,193		Other assets	—		Other liabilities	—		Other liabilities	1,693
		$	32,339		$	1,139		$	10,141		$	3,006