Loans - Presentation of Recorded Investment in Nonaccrual Loans and Loans Past Due Over 90 Days and Still on Accrual by Class of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	$ 19,448	$ 16,747
Commercial Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	11,255	7,999
Commercial Loans [Member] | Nonresidential [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	6,879	3,599
Commercial Loans [Member] | Land [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	134	384
Commercial Loans [Member] | Secured [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	4,242	4,016
Residential Mortgage Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	5,835	6,181
Residential Mortgage Loans [Member] | One-to Four-Family [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	5,835	6,181
Consumer Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	2,358	2,567
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	1,767	1,804
Consumer Loans [Member] | Auto [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	17	23
Consumer Loans [Member] | Marine [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	244	218
Consumer Loans [Member] | Recreational Vehicle [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	327	511
Consumer Loans [Member] | Other [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing receivable, recorded investment, Nonaccrual	$ 3	$ 11