Earnings Per Share ("EPS") - Schedule of Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net income applicable to common stock	$ 1,217	$ 2,353	$ 2,829	$ 1,986	$ 2,324	$ 2,329	$ 6,399	$ 6,639
Average number of common shares outstanding	16,587,563			17,451,763			16,927,496	17,917,077
Less: Average unallocated ESOP shares	(1,150,390)			(1,247,370)			(1,174,787)	(1,271,790)
Average number of common shares outstanding used to calculate basic earnings per common share	15,437,173			16,204,393			15,752,709	16,645,287
Effect of equity-based awards	10,044			57,362			61,613	14,459
Average number of common shares outstanding used to calculate diluted earnings per common share	15,447,217			16,261,755			15,814,322	16,659,746
Earnings per common share:
Basic	$ 0.08			$ 0.12			$ 0.41	$ 0.40
Diluted	$ 0.08			$ 0.12			$ 0.40	$ 0.40