Derivative Financial Instruments (Tables)

12 Months Ended

Sep. 30, 2017

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of derivative positions, notional amounts

The following table summarizes the notional amounts and estimated fair values of the Company’s derivative instruments at September 30, 2017 and 2016.

	September 30, 2017
	Notional Amount		Balance Sheet Location	Positive Fair Value		Negative Fair Value
Derivatives not designated as hedging instruments:	(dollars in thousands)
Interest rate swaps	$	1,061,545	Liabilities	$	1,850	$	(19,005	)
Mortgage loan commitments	37,765		Assets	—		(48		)
Mortgage loan forward sale contracts	43,628		Liabilities	48		—

	September 30, 2016
	Notional Amount		Balance Sheet Location	Positive Fair Value		Negative Fair Value
Derivatives not designated as hedging instruments:	(dollars in thousands)
Interest rate swaps	$	1,055,822	Liabilities	$	525	$	(81,974	)
Mortgage loan commitments	52,333		Assets	66		—
Mortgage loan forward sale contracts	60,529		Liabilities	—		(66		)

Schedule of derivative instruments, effect on other comprehensive income

The effect of derivatives on the consolidated statements of income for the years ended September 30, 2017, 2016 and 2015 was as follows:

		Amount of Gain (Loss) Recognized in Income
		September 30,
Derivatives not designated as hedging instruments:	Location of Gain (Loss) Recognized in Income	2017			2016			2015
		(dollars in thousands)
Interest rate swaps	Noninterest income	$	49,900		$	(48,658	)	$	(62,088	)
Mortgage loan commitments	Noninterest income	(48		)	66			95
Mortgage loan forward sale contracts	Noninterest income	48			(66		)	(95		)

Summary of offsetting assets

The following tables present the Company's gross derivative financial assets and liabilities at September 30, 2017 and 2016, and the related impact of enforceable master netting arrangements and cash collateral, where applicable:

	Gross Amount			Amount Offset			Net Amount Presented in Consolidated Balance Sheets			Held/Pledged Financial Instruments1		Net Amount
September 30, 2017	(dollars in thousands)
Derivative financial assets:
Derivatives subject to master netting arrangement or similar arrangement	$	1,850		$	(1,850	)	$	—		$	—	$	—
Derivative financial liabilities:
Derivatives subject to master netting arrangement or similar arrangement	(19,005		)	1,850			(17,155		)	17,155		—
Total derivative financial liabilities	$	(17,155	)	$	—		$	(17,155	)	$	17,155	$	—
1 The actual amount of collateral exceeds the fair value exposure, at the individual counterparty level, as of the date presented.

	Gross Amount			Amount Offset			Net Amount Presented in Consolidated Balance Sheets			Held/Pledged Financial Instruments1		Net Amount
September 30, 2016	(dollars in thousands)
Derivative financial assets:
Derivatives subject to master netting arrangement or similar arrangement	$	525		$	(525	)	$	—		$	—	$	—
Derivative financial liabilities:
Derivatives subject to master netting arrangement or similar arrangement	(81,974		)	525			(81,449		)	81,449		—
Total derivative financial liabilities	$	(81,449	)	$	—		$	(81,449	)	$	81,449	$	—
1 The actual amount of collateral exceeds the fair value exposure, at the individual counterparty level, as of the date presented.

Summary of offsetting liabilities

The following tables present the Company's gross derivative financial assets and liabilities at September 30, 2017 and 2016, and the related impact of enforceable master netting arrangements and cash collateral, where applicable:

	Gross Amount			Amount Offset			Net Amount Presented in Consolidated Balance Sheets			Held/Pledged Financial Instruments1		Net Amount
September 30, 2017	(dollars in thousands)
Derivative financial assets:
Derivatives subject to master netting arrangement or similar arrangement	$	1,850		$	(1,850	)	$	—		$	—	$	—
Derivative financial liabilities:
Derivatives subject to master netting arrangement or similar arrangement	(19,005		)	1,850			(17,155		)	17,155		—
Total derivative financial liabilities	$	(17,155	)	$	—		$	(17,155	)	$	17,155	$	—
1 The actual amount of collateral exceeds the fair value exposure, at the individual counterparty level, as of the date presented.

	Gross Amount			Amount Offset			Net Amount Presented in Consolidated Balance Sheets			Held/Pledged Financial Instruments1		Net Amount
September 30, 2016	(dollars in thousands)
Derivative financial assets:
Derivatives subject to master netting arrangement or similar arrangement	$	525		$	(525	)	$	—		$	—	$	—
Derivative financial liabilities:
Derivatives subject to master netting arrangement or similar arrangement	(81,974		)	525			(81,449		)	81,449		—
Total derivative financial liabilities	$	(81,449	)	$	—		$	(81,449	)	$	81,449	$	—
1 The actual amount of collateral exceeds the fair value exposure, at the individual counterparty level, as of the date presented.