Fair Value Measurements and Disclosures about Fair Value of Financial Instruments (Fair Value By Balance Sheet Grouping) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Sep. 30, 2018
Residential mortgage loans held for sale Aggregate Fair Value	$ 15,920	$ 9,952
Residential mortgage loans held for sale Aggregate Principal Balance	15,331	9,695
Residential mortgage loans held for sale Difference	$ 589	$ 257