Derivative Instruments and Hedging Activities - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018 USD ($) Instruments	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) Instruments	Dec. 31, 2017 USD ($)	Jun. 30, 2018 USD ($)
Loan Origination Commitments [Member]
Derivative [Line Items]
Pipeline of loans held-for-sale	$ 4,600		$ 4,600		$ 10,800
Counter Party [Member]
Derivative [Line Items]
Financial collateral received under the enforceable master netting arrangement	22,100		22,100		$ 31,600
Interest Expense [Member]
Derivative [Line Items]
Estimated cash flow hedge gain (loss) to be reclassified in next twelve months			(8,300)
Cash Flow Hedges [Member]
Derivative [Line Items]
Reclassifications to interest expense	$ 1,460	$ (1,282)	$ 2,696	$ (2,682)
Cash Flow Hedges [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Number of interest rate derivative instruments held | Instruments	12		12
Derivative, notional amount	$ 900,000		$ 900,000
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Derivative [Line Items]
Reclassifications to interest expense	$ 1,460	$ (997)	$ 2,696	$ (2,122)