Securities - Association's Investments Gross Unrealized Losses and Fair Value of Association's Investments with Unrealized Losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Jun. 30, 2014
Less than 12 Months, Fair Value			$ 30,788
Less than 12 Months, Unrealized Losses			(409)
12 Months or More, Fair Value	$ 13,629		18,753
12 Months or More, Unrealized Losses	(206)		(582)
Total, Fair Value	13,629		49,541
Total, Unrealized Losses	(206)	$ (991)	(991)
Mortgage-backed: GSE Residential [Member]
Less than 12 Months, Fair Value			20,875
Less than 12 Months, Unrealized Losses			(322)
12 Months or More, Fair Value	13,629		18,753
12 Months or More, Unrealized Losses	(206)		(582)
Total, Fair Value	13,629		39,628
Total, Unrealized Losses	$ (206)	(904)	(904)
U.S. Government and Federal Agency and Government Sponsored Enterprises (GSE's) [Member]
Less than 12 Months, Fair Value			9,913
Less than 12 Months, Unrealized Losses			(87)
Total, Fair Value			9,913
Total, Unrealized Losses		$ (87)	$ (87)