Derivative Instruments and Hedging Activities - Fair Values of Derivative Financial Instruments as well as Their Classification on Statement of Financial Condition (Detail) - Derivatives Designated as Hedging Instruments [Member] - Other Assets [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 30, 2018
Derivative [Line Items]
Fair Value	$ 22,109	$ 31,881
Interest Rate Swaps [Member]
Derivative [Line Items]
Fair Value	$ 22,109	$ 31,881