Loans - Presentation of Loans Individually Evaluated for Impairment by Class (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	$ 24,562	$ 24,010	$ 24,403
With no specific allowance recorded, Recorded Investment	12,313	13,677	12,340
With no specific allowance recorded, Average Recorded Investment	12,328	16,155
With no specific allowance recorded, Interest Income Recognized	25	31
With no specific allowance recorded, Cash Basis Income Recognized	18	20
With a specific allowance recorded, Unpaid Principal Balance	32,816	34,261	27,499
With a specific allowance recorded, Recorded Investment	30,298	32,126	27,319
With a specific allowance recorded, Allowance for Loan Losses Allocated	3,022	3,193	2,816
With a specific allowance recorded, Average Recorded Investment	28,809	30,363
With a specific allowance recorded, Interest Income Recognized	417	447
With a specific allowance recorded, Cash Basis Income Recognized	342	295
Total Unpaid Principal Balance	57,378	58,271	51,902
Total Recorded Investment	42,611	45,803	39,659
Total Average Recorded Investment	41,137	46,518
Total Interest Income Recognized	442	478
Total Cash Basis Income Recognized	360	315
Commercial Loans [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	13,638	14,926	13,911
With no specific allowance recorded, Recorded Investment	4,296	6,955	4,390
With no specific allowance recorded, Average Recorded Investment	4,343	8,641
With no specific allowance recorded, Interest Income Recognized	1	1
With no specific allowance recorded, Cash Basis Income Recognized	1	1
With a specific allowance recorded, Unpaid Principal Balance	12,402	9,689	5,488
With a specific allowance recorded, Recorded Investment	9,884	7,554	5,308
With a specific allowance recorded, Allowance for Loan Losses Allocated	1,029	682	568
With a specific allowance recorded, Average Recorded Investment	7,596	5,327
With a specific allowance recorded, Interest Income Recognized	109	37
With a specific allowance recorded, Cash Basis Income Recognized	107	37
Commercial Loans [Member] | Multifamily [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	97	197	165
With no specific allowance recorded, Recorded Investment		85
With no specific allowance recorded, Average Recorded Investment		86
With a specific allowance recorded, Average Recorded Investment		21
Commercial Loans [Member] | Nonresidential [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	1,042	4,258	1,215
With no specific allowance recorded, Recorded Investment	212	2,450	306
With no specific allowance recorded, Average Recorded Investment	259	3,880
With no specific allowance recorded, Interest Income Recognized	1	1
With no specific allowance recorded, Cash Basis Income Recognized	1	1
With a specific allowance recorded, Unpaid Principal Balance	11,348	6,550	5,164
With a specific allowance recorded, Recorded Investment	8,924	6,367	4,984
With a specific allowance recorded, Allowance for Loan Losses Allocated	936	586	565
With a specific allowance recorded, Average Recorded Investment	6,954	3,644
With a specific allowance recorded, Interest Income Recognized	109	37
With a specific allowance recorded, Cash Basis Income Recognized	107	37
Commercial Loans [Member] | Land [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,922	3,958	3,922
With no specific allowance recorded, Recorded Investment	384	532	384
With no specific allowance recorded, Average Recorded Investment	384	532
Commercial Loans [Member] | Construction [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,593	1,126	3,593
With no specific allowance recorded, Recorded Investment		188
With no specific allowance recorded, Average Recorded Investment		439
With a specific allowance recorded, Unpaid Principal Balance		2,815
With a specific allowance recorded, Recorded Investment		863
With a specific allowance recorded, Allowance for Loan Losses Allocated		93
With a specific allowance recorded, Average Recorded Investment		1,338
Commercial Loans [Member] | Secured [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,860	3,898	3,884
With no specific allowance recorded, Recorded Investment	3,700	3,700	3,700
With no specific allowance recorded, Average Recorded Investment	3,700	3,704
With a specific allowance recorded, Unpaid Principal Balance	1,054	324	324
With a specific allowance recorded, Recorded Investment	960	324	324
With a specific allowance recorded, Allowance for Loan Losses Allocated	93	3	3
With a specific allowance recorded, Average Recorded Investment	642	324
Commercial Loans [Member] | Unsecured [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	1,124	1,489	1,132
Residential Mortgage Loans [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	7,875	6,134	7,607
With no specific allowance recorded, Recorded Investment	6,081	4,649	5,866
With no specific allowance recorded, Average Recorded Investment	5,974	5,341
With no specific allowance recorded, Interest Income Recognized	20	18
With no specific allowance recorded, Cash Basis Income Recognized	14	10
With a specific allowance recorded, Unpaid Principal Balance	12,710	14,595	13,482
With a specific allowance recorded, Recorded Investment	12,710	14,595	13,482
With a specific allowance recorded, Allowance for Loan Losses Allocated	1,407	1,707	1,541
With a specific allowance recorded, Average Recorded Investment	13,096	14,630
With a specific allowance recorded, Interest Income Recognized	189	228
With a specific allowance recorded, Cash Basis Income Recognized	136	138
Residential Mortgage Loans [Member] | One-to Four-Family [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	7,875	6,134	7,607
With no specific allowance recorded, Recorded Investment	6,081	4,649	5,866
With no specific allowance recorded, Average Recorded Investment	5,974	5,341
With no specific allowance recorded, Interest Income Recognized	20	18
With no specific allowance recorded, Cash Basis Income Recognized	14	10
With a specific allowance recorded, Unpaid Principal Balance	12,710	14,595	13,482
With a specific allowance recorded, Recorded Investment	12,710	14,595	13,482
With a specific allowance recorded, Allowance for Loan Losses Allocated	1,407	1,707	1,541
With a specific allowance recorded, Average Recorded Investment	13,096	14,630
With a specific allowance recorded, Interest Income Recognized	189	228
With a specific allowance recorded, Cash Basis Income Recognized	136	138
Consumer Loans [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,049	2,950	2,885
With no specific allowance recorded, Recorded Investment	1,936	2,073	2,084
With no specific allowance recorded, Average Recorded Investment	2,011	2,173
With no specific allowance recorded, Interest Income Recognized	4	12
With no specific allowance recorded, Cash Basis Income Recognized	3	9
With a specific allowance recorded, Unpaid Principal Balance	7,704	9,977	8,529
With a specific allowance recorded, Recorded Investment	7,704	9,977	8,529
With a specific allowance recorded, Allowance for Loan Losses Allocated	586	804	707
With a specific allowance recorded, Average Recorded Investment	8,117	10,406
With a specific allowance recorded, Interest Income Recognized	119	182
With a specific allowance recorded, Cash Basis Income Recognized	99	120
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	1,951	2,294	2,245
With no specific allowance recorded, Recorded Investment	1,332	1,679	1,718
With no specific allowance recorded, Average Recorded Investment	1,525	1,739
With no specific allowance recorded, Interest Income Recognized	3	9
With no specific allowance recorded, Cash Basis Income Recognized	2	6
With a specific allowance recorded, Unpaid Principal Balance	6,857	9,256	7,236
With a specific allowance recorded, Recorded Investment	6,857	9,256	7,236
With a specific allowance recorded, Allowance for Loan Losses Allocated	497	687	522
With a specific allowance recorded, Average Recorded Investment	7,047	9,662
With a specific allowance recorded, Interest Income Recognized	110	169
With a specific allowance recorded, Cash Basis Income Recognized	90	114
Consumer Loans [Member] | Auto [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	15	40	20
With no specific allowance recorded, Recorded Investment	9	32	14
With no specific allowance recorded, Average Recorded Investment	12	61
With a specific allowance recorded, Unpaid Principal Balance		5
With a specific allowance recorded, Recorded Investment		5
With a specific allowance recorded, Average Recorded Investment		7
Consumer Loans [Member] | Marine [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	546	519	496
With no specific allowance recorded, Recorded Investment	303	293	271
With no specific allowance recorded, Average Recorded Investment	287	189
With no specific allowance recorded, Interest Income Recognized		2
With no specific allowance recorded, Cash Basis Income Recognized		2
With a specific allowance recorded, Unpaid Principal Balance	159		163
With a specific allowance recorded, Recorded Investment	159		163
With a specific allowance recorded, Allowance for Loan Losses Allocated	3		3
With a specific allowance recorded, Average Recorded Investment	161
With a specific allowance recorded, Interest Income Recognized	2
With a specific allowance recorded, Cash Basis Income Recognized	2
Consumer Loans [Member] | Recreational Vehicle [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	534	97	121
With no specific allowance recorded, Recorded Investment	289	69	78
With no specific allowance recorded, Average Recorded Investment	184	181
With no specific allowance recorded, Interest Income Recognized	1	1
With no specific allowance recorded, Cash Basis Income Recognized	1	1
With a specific allowance recorded, Unpaid Principal Balance	688	716	1,122
With a specific allowance recorded, Recorded Investment	688	716	1,122
With a specific allowance recorded, Allowance for Loan Losses Allocated	86	117	181
With a specific allowance recorded, Average Recorded Investment	905	737
With a specific allowance recorded, Interest Income Recognized	7	13
With a specific allowance recorded, Cash Basis Income Recognized	7	6
Consumer Loans [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3		3
With no specific allowance recorded, Recorded Investment	3		3
With no specific allowance recorded, Average Recorded Investment	3	$ 3
With a specific allowance recorded, Unpaid Principal Balance			8
With a specific allowance recorded, Recorded Investment			8
With a specific allowance recorded, Allowance for Loan Losses Allocated			$ 1
With a specific allowance recorded, Average Recorded Investment	$ 4