Derivative Instruments and Hedging Activities - Pre-tax Effects of Derivative Instruments on Consolidated Statements of Income and Comprehensive Income (Detail) - Derivatives in Cash Flow Hedging Relationships [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives	$ (10,155)	$ 6,207	$ (7,076)	$ 6,452
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	1,460	(1,282)	2,696	(2,682)
Interest Rate Swaps [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives	(10,155)	6,167	(7,076)	6,426
Interest Rate Swaps [Member] | Interest Expense [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	$ 1,460	(997)	$ 2,696	(2,122)
Interest Rate Caps [Member]
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		40		26
Interest Rate Caps [Member] | Interest Expense [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income		$ (285)		$ (560)