Loans - Impaired Financing Receivables by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	$ 66,441	$ 115,123	$ 66,441	$ 115,123	$ 71,140
With no specific allowance recorded, Recorded Investment	42,301	79,932	42,301	79,932	48,081
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	41,643	83,123	43,058	82,099
With no specific allowance recorded, Interest income recognized	262	266	567	572
With no specific allowance recorded, Cash basis income recognized	310	499	696	1,137
With a specific allowance recorded, Unpaid principal balance	7,020	72,894	7,020	72,894	18,115
With a specific allowance recorded, Recorded investment	4,609	48,775	4,609	48,775	12,936
With a specific allowance recorded, Allowance for loan losses allocated	1,046	7,029	1,046	7,029	3,024
With a specific allowance recorded, Average recorded investment	12,125	51,701	13,891	64,076
With a specific allowance recorded, Interest income recognized		(18)	5	232
With a specific allowance recorded, Cash basis income recognized	17	359	35	819
Total Unpaid Principal Balance	73,461	188,017	73,461	188,017	89,255
Total Recorded Investment	46,910	128,707	46,910	128,707	61,017
Total Allowance for Loan Losses Allocated.	1,046	7,029	1,046	7,029	3,024
Total Average Recorded Investment	53,768	134,824	56,949	146,175
Total Interest Income, Accrual Method	262	248	572	804
Total cash basis income recognized	327	858	731	1,956
Permanent Real Estate Loans [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	30,737	73,764	30,737	73,764	37,662
With no specific allowance recorded, Recorded Investment	23,944	64,437	23,944	64,437	34,467
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	25,719	66,134	29,243	65,633
With no specific allowance recorded, Interest income recognized	150	204	317	415
With no specific allowance recorded, Cash basis income recognized	161	342	354	776
With a specific allowance recorded, Unpaid principal balance	2,528	42,283	2,528	42,283	10,862
With a specific allowance recorded, Recorded investment	2,089	35,756	2,089	35,756	8,546
With a specific allowance recorded, Allowance for loan losses allocated	351	5,328	351	5,328	2,380
With a specific allowance recorded, Average recorded investment	9,057	37,789	9,288	44,508
With a specific allowance recorded, Interest income recognized		(22)	5	222
With a specific allowance recorded, Cash basis income recognized	17	346	35	787
Permanent Real Estate Loans [Member] | One-to Four-Family Residential [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	19,608	33,074	19,608	33,074	18,672
With no specific allowance recorded, Recorded Investment	17,484	29,040	17,484	29,040	16,947
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	17,469	28,780	16,870	27,751
With no specific allowance recorded, Interest income recognized	148	221	305	311
With no specific allowance recorded, Cash basis income recognized	155	266	323	426
With a specific allowance recorded, Unpaid principal balance	17	3,969	17	3,969	735
With a specific allowance recorded, Recorded investment	10	3,604	10	3,604	735
With a specific allowance recorded, Allowance for loan losses allocated	1	648	1	648	260
With a specific allowance recorded, Average recorded investment	373	2,117	370	2,608
With a specific allowance recorded, Interest income recognized				49
With a specific allowance recorded, Cash basis income recognized		5		61
Permanent Real Estate Loans [Member] | Multi-Family Residential [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	755	7,190	755	7,190	1,173
With no specific allowance recorded, Recorded Investment	660	4,861	660	4,861	1,078
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	671	4,367	734	4,317
With no specific allowance recorded, Interest income recognized		50	2	19
With no specific allowance recorded, Cash basis income recognized	1	85	4	97
With a specific allowance recorded, Unpaid principal balance	185	5,572	185	5,572	996
With a specific allowance recorded, Recorded investment	85	5,193	85	5,193	981
With a specific allowance recorded, Allowance for loan losses allocated	25	731	25	731	57
With a specific allowance recorded, Average recorded investment	575	3,784	785	3,201
With a specific allowance recorded, Interest income recognized				41
With a specific allowance recorded, Cash basis income recognized		22		76
Permanent Real Estate Loans [Member] | Nonresidential [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	6,461	26,409	6,461	26,409	13,240
With no specific allowance recorded, Recorded Investment	5,313	24,740	5,313	24,740	12,638
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	5,485	26,959	8,688	27,257
With no specific allowance recorded, Interest income recognized	2	(75)	10	69
With no specific allowance recorded, Cash basis income recognized	5	(45)	27	201
With a specific allowance recorded, Unpaid principal balance	2,326	27,410	2,326	27,410	5,218
With a specific allowance recorded, Recorded investment	1,994	23,820	1,994	23,820	4,703
With a specific allowance recorded, Allowance for loan losses allocated	325	3,469	325	3,469	1,336
With a specific allowance recorded, Average recorded investment	7,045	28,931	6,477	34,570
With a specific allowance recorded, Interest income recognized		(22)	5	132
With a specific allowance recorded, Cash basis income recognized	17	319	35	650
Permanent Real Estate Loans [Member] | Land [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	3,913	7,091	3,913	7,091	4,577
With no specific allowance recorded, Recorded Investment	487	5,796	487	5,796	3,804
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	2,094	6,028	2,951	6,308
With no specific allowance recorded, Interest income recognized		8		16
With no specific allowance recorded, Cash basis income recognized		36		52
With a specific allowance recorded, Unpaid principal balance		5,332		5,332	3,913
With a specific allowance recorded, Recorded investment		3,139		3,139	2,127
With a specific allowance recorded, Allowance for loan losses allocated		480		480	727
With a specific allowance recorded, Average recorded investment	1,064	2,957	1,656	4,129
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Construction Loans [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	13,409	14,823	13,409	14,823	18,483
With no specific allowance recorded, Recorded Investment	2,081	7,760	2,081	7,760	3,580
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	1,804	9,036	2,435	10,267
With no specific allowance recorded, Interest income recognized		10		53
With no specific allowance recorded, Cash basis income recognized		55	2	137
With a specific allowance recorded, Unpaid principal balance	3,921	29,580	3,921	29,580	6,455
With a specific allowance recorded, Recorded investment	2,316	12,398	2,316	12,398	3,967
With a specific allowance recorded, Allowance for loan losses allocated	685	1,498	685	1,498	478
With a specific allowance recorded, Average recorded investment	2,864	13,325	4,280	17,140
With a specific allowance recorded, Interest income recognized		5		10
With a specific allowance recorded, Cash basis income recognized		12		29
Construction Loans [Member] | One-to Four-Family Residential [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	13,409	14,116	13,409	14,116	17,912
With no specific allowance recorded, Recorded Investment	2,081	7,760	2,081	7,760	3,580
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	1,804	9,036	2,435	10,267
With no specific allowance recorded, Interest income recognized		10		53
With no specific allowance recorded, Cash basis income recognized		55	2	137
With a specific allowance recorded, Unpaid principal balance	3,921	29,580	3,921	29,580	6,455
With a specific allowance recorded, Recorded investment	2,316	12,398	2,316	12,398	3,967
With a specific allowance recorded, Allowance for loan losses allocated	685	1,498	685	1,498	478
With a specific allowance recorded, Average recorded investment	2,864	13,325	4,280	17,140
With a specific allowance recorded, Interest income recognized		5		10
With a specific allowance recorded, Cash basis income recognized		12		29
Construction Loans [Member] | Multi-Family and Nonresidential [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance		707		707	571
With no specific allowance recorded, Recorded Investment
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment
With no specific allowance recorded, Interest income recognized
With no specific allowance recorded, Cash basis income recognized
With a specific allowance recorded, Unpaid principal balance
With a specific allowance recorded, Recorded investment
With a specific allowance recorded, Allowance for loan losses allocated
With a specific allowance recorded, Average recorded investment
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Consumer Loans [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	12,544	7,515	12,544	7,515	10,012
With no specific allowance recorded, Recorded Investment	11,763	6,031	11,763	6,031	8,784
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	10,936	5,806	9,120	4,000
With no specific allowance recorded, Interest income recognized	112	52	249	91
With no specific allowance recorded, Cash basis income recognized	128	75	279	142
With a specific allowance recorded, Unpaid principal balance		88		88
With a specific allowance recorded, Recorded investment		36		36
With a specific allowance recorded, Allowance for loan losses allocated		18		18
With a specific allowance recorded, Average recorded investment		36	9	148
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Consumer Loans [Member] | Home Equity [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	11,041	6,122	11,041	6,122	8,867
With no specific allowance recorded, Recorded Investment	10,423	4,953	10,423	4,953	7,958
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	9,649	4,683	8,053	3,388
With no specific allowance recorded, Interest income recognized	107	51	232	90
With no specific allowance recorded, Cash basis income recognized	119	58	255	109
With a specific allowance recorded, Unpaid principal balance
With a specific allowance recorded, Recorded investment
With a specific allowance recorded, Allowance for loan losses allocated
With a specific allowance recorded, Average recorded investment
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Consumer Loans [Member] | Auto [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	65	78	65	78	68
With no specific allowance recorded, Recorded Investment	44	58	44	58	44
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	41	56	44	60
With no specific allowance recorded, Interest income recognized		1	1	1
With no specific allowance recorded, Cash basis income recognized	1	2	2	3
With a specific allowance recorded, Unpaid principal balance
With a specific allowance recorded, Recorded investment
With a specific allowance recorded, Allowance for loan losses allocated
With a specific allowance recorded, Average recorded investment
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Consumer Loans [Member] | Marine [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	186	368	186	368	190
With no specific allowance recorded, Recorded Investment	186	354	186	354	190
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	187	356	184	178
With no specific allowance recorded, Interest income recognized
With no specific allowance recorded, Cash basis income recognized	2	4	5	9
With a specific allowance recorded, Unpaid principal balance
With a specific allowance recorded, Recorded investment
With a specific allowance recorded, Allowance for loan losses allocated
With a specific allowance recorded, Average recorded investment				121
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Consumer Loans [Member] | Recreational Vehicles [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	1,252	940	1,252	940	887
With no specific allowance recorded, Recorded Investment	1,110	659	1,110	659	592
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	1,055	704	835	367
With no specific allowance recorded, Interest income recognized	5		16
With no specific allowance recorded, Cash basis income recognized	6	11	17	21
With a specific allowance recorded, Unpaid principal balance		88		88
With a specific allowance recorded, Recorded investment		36		36
With a specific allowance recorded, Allowance for loan losses allocated		18		18
With a specific allowance recorded, Average recorded investment		36	9	27
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Consumer Loans [Member] | Others [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance		7		7
With no specific allowance recorded, Recorded Investment		7		7
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	4	7	4	7
With no specific allowance recorded, Interest income recognized
With no specific allowance recorded, Cash basis income recognized
With a specific allowance recorded, Unpaid principal balance
With a specific allowance recorded, Recorded investment
With a specific allowance recorded, Allowance for loan losses allocated
With a specific allowance recorded, Average recorded investment
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized
Commercial Loans [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	9,751	19,021	9,751	19,021	4,983
With no specific allowance recorded, Recorded Investment	4,513	1,704	4,513	1,704	1,250
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	3,184	2,147	2,260	2,199
With no specific allowance recorded, Interest income recognized			1	13
With no specific allowance recorded, Cash basis income recognized	21	27	61	82
With a specific allowance recorded, Unpaid principal balance	571	943	571	943	798
With a specific allowance recorded, Recorded investment	204	585	204	585	423
With a specific allowance recorded, Allowance for loan losses allocated	10	185	10	185	166
With a specific allowance recorded, Average recorded investment	204	551	314	2,280
With a specific allowance recorded, Interest income recognized		(1)
With a specific allowance recorded, Cash basis income recognized		1		3
Commercial Loans [Member] | Secured [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	5,380	2,317	5,380	2,317	2,122
With no specific allowance recorded, Recorded Investment	4,512	1,497	4,512	1,497	1,212
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	2,827	1,665	2,061	1,747
With no specific allowance recorded, Interest income recognized		5		12
With no specific allowance recorded, Cash basis income recognized	15	27	33	69
With a specific allowance recorded, Unpaid principal balance	571	943	571	943	798
With a specific allowance recorded, Recorded investment	204	585	204	585	423
With a specific allowance recorded, Allowance for loan losses allocated	10	185	10	185	166
With a specific allowance recorded, Average recorded investment	204	551	314	2,161
With a specific allowance recorded, Interest income recognized		(1)
With a specific allowance recorded, Cash basis income recognized		1		3
Commercial Loans [Member] | Unsecured [Member]
Schedule Of Financial Receivables [Line Items]
With no specific allowance recorded, Unpaid principal Balance	4,371	16,704	4,371	16,704	2,861
With no specific allowance recorded, Recorded Investment	1	207	1	207	38
With no specific allowance recorded, Allowance for loan losses allocated
With no specific allowance recorded, Average recorded investment	357	482	199	452
With no specific allowance recorded, Interest income recognized		(5)	1	1
With no specific allowance recorded, Cash basis income recognized	6		28	13
With a specific allowance recorded, Unpaid principal balance
With a specific allowance recorded, Recorded investment
With a specific allowance recorded, Allowance for loan losses allocated
With a specific allowance recorded, Average recorded investment				119
With a specific allowance recorded, Interest income recognized
With a specific allowance recorded, Cash basis income recognized