Summary of Financial Effects of Troubled Debt Restructurings (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Investment	Dec. 31, 2018 USD ($) Investment	Dec. 31, 2017 USD ($) Investment
Financing Receivable, Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment	73	22	71
Pre-Modification Recorded Investment	$ 35,287	$ 8,663	$ 61,641
Post-Modification Recorded Investment	30,816	6,355	36,047
Trouble debt restructuring, charge-off amount	4,471	$ 2,308	14,273
Capitalized interest	$ 3		$ 12
One-to-four family
Financing Receivable, Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment	1		4
Pre-Modification Recorded Investment	$ 131		$ 810
Post-Modification Recorded Investment	$ 131		$ 986
Weighted Average Interest Rate, Pre-Modification	5.50%		5.93%
Weighted Average Interest Rate, Post-Modification	5.50%		2.21%
Capitalized interest			$ 12
Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment	72	21	65
Pre-Modification Recorded Investment	$ 35,156	$ 7,763	$ 52,179
Post-Modification Recorded Investment	$ 30,685	$ 5,455	$ 26,409
Weighted Average Interest Rate, Pre-Modification	4.31%	3.25%	3.36%
Weighted Average Interest Rate, Post-Modification	4.37%	3.13%	3.29%
Trouble debt restructuring, charge-off amount	$ 4,471	$ 2,308	$ 14,273
Capitalized interest	$ 0
Acquisition, development, and construction
Financing Receivable, Modifications [Line Items]
Number of loans classified as a non-accrual TDRs | Investment		1	2
Pre-Modification Recorded Investment		$ 900	$ 8,652
Post-Modification Recorded Investment		$ 900	$ 8,652
Weighted Average Interest Rate, Pre-Modification		4.50%	5.50%
Weighted Average Interest Rate, Post-Modification		4.50%	5.50%