Benefit Plans - Schedule of Impact of Retrospective Application to Consolidated Statement of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Miscellaneous non-interest expense:
Miscellaneous	$ 3,479	$ 2,625	$ 6,832	$ 5,188
Salaries and employee benefits:
Salaries and employee benefits	$ 15,699	12,852	$ 31,341	25,645
As Previously Reported [Member]
Miscellaneous non-interest expense:
Miscellaneous		2,551		5,040
Salaries and employee benefits:
Salaries and employee benefits		12,926		25,793
As Reported Under the New Guidance [Member]
Miscellaneous non-interest expense:
Miscellaneous		2,625		5,188
Salaries and employee benefits:
Salaries and employee benefits		$ 12,852		$ 25,645