Loans - Presentation of Loans Individually Evaluated for Impairment by Class (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	$ 29,796	$ 29,796		$ 27,869
With no specific allowance recorded, Recorded Investment	17,331	17,331		16,138
With no specific allowance recorded, Average Recorded Investment		23,701
With no specific allowance recorded, Interest Income Recognized		35
With no specific allowance recorded, Cash Basis Income Recognized		295
With a specific allowance recorded, Unpaid Principal Balance	32,067	32,067		32,120
With a specific allowance recorded, Recorded Investment	29,749	29,749		29,759
With a specific allowance recorded, Allowance for Loan Losses Allocated	3,625	3,625		3,310
With a specific allowance recorded, Average Recorded Investment	31,265	23,719
With a specific allowance recorded, Interest Income Recognized	277	551
With a specific allowance recorded, Cash Basis Income Recognized	289	583
Total Unpaid Principal Balance	61,863	61,863		59,989
Loans individually evaluated for impairment	47,080	47,080	$ 43,854	45,897
Loans individually evaluated for impairment	3,625	3,625	3,085	3,310
Total Average Recorded Investment		47,420
Total Interest Income, Accrual Method		586
Total Cash Basis Income Recognized		878
Commercial Loans [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	18,916	18,916		19,631
With no specific allowance recorded, Recorded Investment	8,749	8,749		10,089
With no specific allowance recorded, Average Recorded Investment		10,153
With no specific allowance recorded, Cash Basis Income Recognized		79
With a specific allowance recorded, Unpaid Principal Balance	5,698	5,698		7,116
With a specific allowance recorded, Recorded Investment	3,568	3,568		4,756
With a specific allowance recorded, Allowance for Loan Losses Allocated	289	289		717
With a specific allowance recorded, Average Recorded Investment	4,321	3,643
With a specific allowance recorded, Interest Income Recognized	1	2
With a specific allowance recorded, Cash Basis Income Recognized	3	7
Loans individually evaluated for impairment			13,592	14,845
Loans individually evaluated for impairment			673	717
Commercial Loans [Member] | Multifamily [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	185	185		185
With no specific allowance recorded, Recorded Investment	86	86		85
With no specific allowance recorded, Average Recorded Investment		347
With a specific allowance recorded, Unpaid Principal Balance	73	73		33
With a specific allowance recorded, Recorded Investment	48	48		8
With a specific allowance recorded, Allowance for Loan Losses Allocated	6	6		6
With a specific allowance recorded, Average Recorded Investment	567	326
Commercial Loans [Member] | Nonresidential [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	5,304	5,304		7,201
With no specific allowance recorded, Recorded Investment	3,684	3,684		5,582
With no specific allowance recorded, Average Recorded Investment		4,536
With no specific allowance recorded, Cash Basis Income Recognized		20
With a specific allowance recorded, Unpaid Principal Balance	1,865	1,865		3,944
With a specific allowance recorded, Recorded Investment	1,385	1,385		3,561
With a specific allowance recorded, Allowance for Loan Losses Allocated	78	78		615
With a specific allowance recorded, Average Recorded Investment	1,404	1,015
With a specific allowance recorded, Interest Income Recognized	1	2
With a specific allowance recorded, Cash Basis Income Recognized	3	7
Commercial Loans [Member] | Land [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,958	3,958		3,958
With no specific allowance recorded, Recorded Investment	532	532		532
With no specific allowance recorded, Average Recorded Investment		498
Commercial Loans [Member] | Construction [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	1,741	1,741		1,126
With no specific allowance recorded, Recorded Investment	739	739		188
With no specific allowance recorded, Average Recorded Investment		824
With a specific allowance recorded, Unpaid Principal Balance	3,436	3,436		2,815
With a specific allowance recorded, Recorded Investment	1,811	1,811		863
With a specific allowance recorded, Allowance for Loan Losses Allocated	202	202		93
With a specific allowance recorded, Average Recorded Investment	2,026	2,140
Commercial Loans [Member] | Secured [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,945	3,945		3,903
With no specific allowance recorded, Recorded Investment	3,708	3,708		3,702
With no specific allowance recorded, Average Recorded Investment		3,948
With no specific allowance recorded, Cash Basis Income Recognized		2
With a specific allowance recorded, Unpaid Principal Balance	324	324		324
With a specific allowance recorded, Recorded Investment	324	324		324
With a specific allowance recorded, Allowance for Loan Losses Allocated	3	3		3
With a specific allowance recorded, Average Recorded Investment	324	162
Commercial Loans [Member] | Unsecured [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,783	3,783		3,258
With no specific allowance recorded, Cash Basis Income Recognized		57
Residential Mortgage Loans [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	7,571	7,571		6,015
With no specific allowance recorded, Recorded Investment	6,020	6,020		4,518
With no specific allowance recorded, Average Recorded Investment		8,558
With no specific allowance recorded, Interest Income Recognized		29
With no specific allowance recorded, Cash Basis Income Recognized		148
With a specific allowance recorded, Unpaid Principal Balance	15,252	15,252		14,691
With a specific allowance recorded, Recorded Investment	15,252	15,252		14,691
With a specific allowance recorded, Allowance for Loan Losses Allocated	2,246	2,246		1,751
With a specific allowance recorded, Average Recorded Investment	15,742	11,761
With a specific allowance recorded, Interest Income Recognized	145	292
With a specific allowance recorded, Cash Basis Income Recognized	148	305
Loans individually evaluated for impairment			19,239	19,209
Loans individually evaluated for impairment			1,651	1,751
Residential Mortgage Loans [Member] | One-to Four-Family [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	7,571	7,571		6,015
With no specific allowance recorded, Recorded Investment	6,020	6,020		4,518
With no specific allowance recorded, Average Recorded Investment		8,558
With no specific allowance recorded, Interest Income Recognized		29
With no specific allowance recorded, Cash Basis Income Recognized		148
With a specific allowance recorded, Unpaid Principal Balance	15,252	15,252		14,691
With a specific allowance recorded, Recorded Investment	15,252	15,252		14,691
With a specific allowance recorded, Allowance for Loan Losses Allocated	2,246	2,246		1,751
With a specific allowance recorded, Average Recorded Investment	15,742	11,761
With a specific allowance recorded, Interest Income Recognized	145	292
With a specific allowance recorded, Cash Basis Income Recognized	148	305
Consumer Loans [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	3,309	3,309		2,223
With no specific allowance recorded, Recorded Investment	2,562	2,562		1,531
With no specific allowance recorded, Average Recorded Investment		4,990
With no specific allowance recorded, Interest Income Recognized		6
With no specific allowance recorded, Cash Basis Income Recognized		68
With a specific allowance recorded, Unpaid Principal Balance	11,117	11,117		10,313
With a specific allowance recorded, Recorded Investment	10,929	10,929		10,312
With a specific allowance recorded, Allowance for Loan Losses Allocated	1,090	1,090		842
With a specific allowance recorded, Average Recorded Investment	11,202	8,315
With a specific allowance recorded, Interest Income Recognized	131	257
With a specific allowance recorded, Cash Basis Income Recognized	138	271
Loans individually evaluated for impairment			11,023	11,843
Loans individually evaluated for impairment			$ 761	842
Consumer Loans [Member] | Home Equity [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	2,509	2,509		1,901
With no specific allowance recorded, Recorded Investment	1,998	1,998		1,262
With no specific allowance recorded, Average Recorded Investment		4,517
With no specific allowance recorded, Interest Income Recognized		3
With no specific allowance recorded, Cash Basis Income Recognized		46
With a specific allowance recorded, Unpaid Principal Balance	10,348	10,348		9,577
With a specific allowance recorded, Recorded Investment	10,160	10,160		9,577
With a specific allowance recorded, Allowance for Loan Losses Allocated	949	949		722
With a specific allowance recorded, Average Recorded Investment	10,399	7,568
With a specific allowance recorded, Interest Income Recognized	124	246
With a specific allowance recorded, Cash Basis Income Recognized	131	260
Consumer Loans [Member] | Auto [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	94	94		47
With no specific allowance recorded, Recorded Investment	79	79		37
With no specific allowance recorded, Average Recorded Investment		57
With no specific allowance recorded, Cash Basis Income Recognized		5
With a specific allowance recorded, Unpaid Principal Balance	8	8		7
With a specific allowance recorded, Recorded Investment	8	8		6
With a specific allowance recorded, Allowance for Loan Losses Allocated				1
With a specific allowance recorded, Average Recorded Investment	9	4
Consumer Loans [Member] | Marine [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	156	156		151
With no specific allowance recorded, Recorded Investment	156	156		151
With no specific allowance recorded, Average Recorded Investment		159
With no specific allowance recorded, Cash Basis Income Recognized		5
Consumer Loans [Member] | Recreational Vehicle [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	544	544		124
With no specific allowance recorded, Recorded Investment	323	323		81
With no specific allowance recorded, Average Recorded Investment		255
With no specific allowance recorded, Interest Income Recognized		3
With no specific allowance recorded, Cash Basis Income Recognized		12
With a specific allowance recorded, Unpaid Principal Balance	761	761		729
With a specific allowance recorded, Recorded Investment	761	761		729
With a specific allowance recorded, Allowance for Loan Losses Allocated	141	141		$ 119
With a specific allowance recorded, Average Recorded Investment	794	743
With a specific allowance recorded, Interest Income Recognized	7	11
With a specific allowance recorded, Cash Basis Income Recognized	7	11
Consumer Loans [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
With no specific allowance recorded, Unpaid Principal Balance	6	6
With no specific allowance recorded, Recorded Investment	$ 6	6
With no specific allowance recorded, Average Recorded Investment		$ 2