Loans - Loans by Class Modified as Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($) Loan	Sep. 30, 2015 USD ($) Loan	Sep. 30, 2016 USD ($) Loan	Sep. 30, 2015 USD ($) Loan
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	2	7	10	23
Pre-Modification Outstanding Recorded Investment	$ 1,484	$ 334	$ 6,018	$ 1,726
Post-Modification Recorded Investment	$ 1,491	$ 367	$ 6,048	$ 1,780
Commercial Loans [Member]
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	1		3
Pre-Modification Outstanding Recorded Investment	$ 1,371		$ 5,459
Post-Modification Recorded Investment	$ 1,377		$ 5,465
Commercial Loans [Member] | Nonresidential [Member]
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	1		3
Pre-Modification Outstanding Recorded Investment	$ 1,371		$ 5,459
Post-Modification Recorded Investment	$ 1,377		$ 5,465
Residential Mortgage Loans [Member]
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	1	2	4	12
Pre-Modification Outstanding Recorded Investment	$ 113	$ 156	$ 429	$ 1,066
Post-Modification Recorded Investment	$ 114	$ 189	$ 449	$ 1,119
Residential Mortgage Loans [Member] | One-to Four-Family [Member]
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	1	2	4	12
Pre-Modification Outstanding Recorded Investment	$ 113	$ 156	$ 429	$ 1,066
Post-Modification Recorded Investment	$ 114	$ 189	$ 449	$ 1,119
Consumer Loans [Member]
Financing Receivable Modifications [Line Items]
Number of Loans | Loan		5	3	11
Pre-Modification Outstanding Recorded Investment		$ 178	$ 130	$ 660
Post-Modification Recorded Investment		$ 178	$ 134	$ 661
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable Modifications [Line Items]
Number of Loans | Loan		5	3	11
Pre-Modification Outstanding Recorded Investment		$ 178	$ 130	$ 660
Post-Modification Recorded Investment		$ 178	$ 134	$ 661