Loans, Nonaccrual and past due loans (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 Contract Loan	Dec. 31, 2011 Contract
Past due and nonaccrual [Line Items]
Nonaccrual loans	$ 3,003,000	$ 5,218,000
30 to 59 days past due	3,821,000	6,072,000
60 to 89 days past due	940,000	1,244,000
Greater than 90 days past due	1,720,000	3,446,000
Recorded investment 90 days or greater and accruing	81,000	0
Total past due	6,562,000	10,762,000
Current	322,739,000	291,547,000
Loans	329,301,000	302,309,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	6,606,000	6,687,000
With related allowance recorded	5,387,000	6,932,000
Total investments	11,993,000	13,619,000
With no related allowance unpaid principal balance	7,247,000	6,734,000
With related allowance unpaid principal balance	5,582,000	7,138,000
Total unpaid principal balance	12,829,000	13,872,000
Related allowance	1,018,000	1,254,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	14,106,000	11,515,000
Interest income recognized	524,000	297,000
Impaired loans, interest income forgone	269,000	306,000
Commitments to lend additional funds to borrowers whose loans were classified as nonaccrual, TDR or impaired	0	0
Trouble debt restructuring, recorded investment	7,700,000	6,900,000
Restructured loans by modification [Abstract]
Number of contracts	9	12
Rate modifications	0	3,734,000
Term modifications	0	0
Payment modifications	0	0
Combination modifications	1,775,000	0
Total modifications	1,775,000	3,734,000
TDR modifications, subsequent default	1,570,000	5,300,000
Loans that became delinquent more than 90 days past due or transferred to nonaccrual within 12 months of restructuring [Abstract]
Number of days past due to be considered in default	P31D
Number of days past due to be considered nonaccrual status	P90D
Number of mortgages over 90 days past due and considered nonaccrual status	1
Annual adjustable rate over rolling cost of funds (in hundredths)	1.00%
Discount on market loan rate for consumer loans to employees and officers (in hundredths)	1.00%
Director and Officer Loans [Roll Forward]
Balance, beginning of period	5,376,000	5,695,000
Advances	417,000	1,269,000
Repayments	(301,000)	(1,588,000)
Balance, end of period	5,492,000	5,376,000
Secured real estate loans that have loan-to-value ratios above 100%	1,100,000	1,500,000
One-to four- family [Member]
Past due and nonaccrual [Line Items]
Nonaccrual loans	1,013,000	3,124,000
30 to 59 days past due	2,238,000	4,321,000
60 to 89 days past due	572,000	935,000
Greater than 90 days past due	836,000	2,683,000
Recorded investment 90 days or greater and accruing	81,000	0
Total past due	3,727,000	7,939,000
Current	92,057,000	88,366,000
Loans	95,784,000	96,305,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	2,521,000	3,104,000
With related allowance recorded	3,495,000	5,156,000
Total investments	6,016,000	8,260,000
With no related allowance unpaid principal balance	2,826,000	3,104,000
With related allowance unpaid principal balance	3,651,000	5,280,000
Total unpaid principal balance	6,477,000	8,384,000
Related allowance	392,000	541,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	7,451,000	6,157,000
Interest income recognized	266,000	190,000
Restructured loans by modification [Abstract]
Number of contracts	3	5
Rate modifications	0	1,350,000
Term modifications	0	0
Payment modifications	0	0
Combination modifications	673,000	0
Total modifications	673,000	1,350,000
TDR modifications, subsequent default	673,000	2,882,000
Home equity [Member]
Past due and nonaccrual [Line Items]
Nonaccrual loans	332,000	731,000
30 to 59 days past due	886,000	583,000
60 to 89 days past due	364,000	176,000
Greater than 90 days past due	332,000	683,000
Recorded investment 90 days or greater and accruing	0	0
Total past due	1,582,000	1,442,000
Current	33,782,000	38,214,000
Loans	35,364,000	39,656,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	949,000	773,000
With related allowance recorded	782,000	1,011,000
Total investments	1,731,000	1,784,000
With no related allowance unpaid principal balance	1,132,000	773,000
With related allowance unpaid principal balance	782,000	1,038,000
Total unpaid principal balance	1,914,000	1,811,000
Related allowance	247,000	447,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	1,909,000	1,505,000
Interest income recognized	74,000	28,000
Restructured loans by modification [Abstract]
Number of contracts	1	2
Rate modifications	0	391,000
Term modifications	0	0
Payment modifications	0	0
Combination modifications	116,000	0
Total modifications	116,000	391,000
TDR modifications, subsequent default	116,000	955,000
Commercial and multifamily [Member]
Past due and nonaccrual [Line Items]
Nonaccrual loans	1,106,000	1,299,000
30 to 59 days past due	0	0
60 to 89 days past due	0	0
Greater than 90 days past due	0	0
Recorded investment 90 days or greater and accruing	0	0
Total past due	0	0
Current	133,620,000	106,016,000
Loans	133,620,000	106,016,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	1,883,000	1,784,000
With related allowance recorded	244,000	219,000
Total investments	2,127,000	2,003,000
With no related allowance unpaid principal balance	1,883,000	1,784,000
With related allowance unpaid principal balance	244,000	219,000
Total unpaid principal balance	2,127,000	2,003,000
Related allowance	70,000	38,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	2,188,000	2,998,000
Interest income recognized	90,000	9,000
Restructured loans by modification [Abstract]
Number of contracts	2	3
Rate modifications	0	1,963,000
Term modifications	0	0
Payment modifications	0	0
Combination modifications	422,000	0
Total modifications	422,000	1,963,000
TDR modifications, subsequent default	241,000	1,357,000
Construction and land [Member]
Past due and nonaccrual [Line Items]
Nonaccrual loans	471,000	0
30 to 59 days past due	243,000	0
60 to 89 days past due	0	123,000
Greater than 90 days past due	471,000	80,000
Recorded investment 90 days or greater and accruing	0	0
Total past due	714,000	203,000
Current	24,744,000	17,602,000
Loans	25,458,000	17,805,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	495,000	779,000
With related allowance recorded	76,000	123,000
Total investments	571,000	902,000
With no related allowance unpaid principal balance	608,000	785,000
With related allowance unpaid principal balance	76,000	178,000
Total unpaid principal balance	684,000	963,000
Related allowance	25,000	37,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	711,000	307,000
Interest income recognized	23,000	47,000
Restructured loans by modification [Abstract]
TDR modifications, subsequent default	0	80,000
Manufactured homes [Member]
Past due and nonaccrual [Line Items]
30 to 59 days past due	326,000	327,000
60 to 89 days past due	2,000	7,000
Greater than 90 days past due	0	0
Recorded investment 90 days or greater and accruing	0	0
Total past due	328,000	334,000
Current	15,904,000	18,110,000
Loans	16,232,000	18,444,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	67,000	0
With related allowance recorded	587,000	122,000
Total investments	654,000	122,000
With no related allowance unpaid principal balance	67,000	0
With related allowance unpaid principal balance	587,000	122,000
Total unpaid principal balance	654,000	122,000
Related allowance	117,000	11,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	740,000	139,000
Interest income recognized	48,000	13,000
Other consumer [Member]
Past due and nonaccrual [Line Items]
Nonaccrual loans	1,000	0
30 to 59 days past due	65,000	172,000
60 to 89 days past due	2,000	3,000
Greater than 90 days past due	1,000	0
Recorded investment 90 days or greater and accruing	0	0
Total past due	68,000	175,000
Current	8,582,000	10,745,000
Loans	8,650,000	10,920,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	9,000	14,000
With related allowance recorded	46,000	87,000
Total investments	55,000	101,000
With no related allowance unpaid principal balance	49,000	55,000
With related allowance unpaid principal balance	46,000	87,000
Total unpaid principal balance	95,000	142,000
Related allowance	22,000	48,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	104,000	96,000
Interest income recognized	5,000	5,000
Restructured loans by modification [Abstract]
Number of contracts		1
Rate modifications		4,000
Term modifications		0
Payment modifications		0
Combination modifications		0
Total modifications		4,000
Commercial business [Member]
Past due and nonaccrual [Line Items]
Nonaccrual loans	80,000	64,000
30 to 59 days past due	63,000	669,000
60 to 89 days past due	0	0
Greater than 90 days past due	80,000	0
Recorded investment 90 days or greater and accruing	0	0
Total past due	143,000	669,000
Current	14,050,000	12,494,000
Loans	14,193,000	13,163,000
Impaired Financing Receivable, Recorded Investment [Abstract]
With no related allowance recorded	682,000	233,000
With related allowance recorded	157,000	214,000
Total investments	839,000	447,000
With no related allowance unpaid principal balance	682,000	233,000
With related allowance unpaid principal balance	196,000	214,000
Total unpaid principal balance	878,000	447,000
Related allowance	145,000	132,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	1,003,000	313,000
Interest income recognized	18,000	5,000
Restructured loans by modification [Abstract]
Number of contracts	3	1
Rate modifications	0	26,000
Term modifications	0	0
Payment modifications	0	0
Combination modifications	564,000	0
Total modifications	564,000	26,000
TDR modifications, subsequent default	540,000	26,000
Performing [Member]
Past due and nonaccrual [Line Items]
Loans	325,389,000	295,672,000
Performing [Member] | One-to four- family [Member]
Past due and nonaccrual [Line Items]
Loans	94,641,000	91,904,000
Performing [Member] | Home equity [Member]
Past due and nonaccrual [Line Items]
Loans	34,647,000	38,783,000
Performing [Member] | Commercial and multifamily [Member]
Past due and nonaccrual [Line Items]
Loans	132,273,000	104,797,000
Performing [Member] | Construction and land [Member]
Past due and nonaccrual [Line Items]
Loans	24,987,000	17,725,000
Performing [Member] | Manufactured homes [Member]
Past due and nonaccrual [Line Items]
Loans	16,203,000	18,444,000
Performing [Member] | Other consumer [Member]
Past due and nonaccrual [Line Items]
Loans	8,642,000	10,856,000
Performing [Member] | Commercial business [Member]
Past due and nonaccrual [Line Items]
Loans	13,996,000	13,163,000
Nonperforming [Member]
Past due and nonaccrual [Line Items]
Loans	3,912,000	6,637,000
Nonperforming [Member] | One-to four- family [Member]
Past due and nonaccrual [Line Items]
Loans	1,143,000	4,401,000
Nonperforming [Member] | Home equity [Member]
Past due and nonaccrual [Line Items]
Loans	717,000	873,000
Nonperforming [Member] | Commercial and multifamily [Member]
Past due and nonaccrual [Line Items]
Loans	1,347,000	1,219,000
Nonperforming [Member] | Construction and land [Member]
Past due and nonaccrual [Line Items]
Loans	471,000	80,000
Nonperforming [Member] | Manufactured homes [Member]
Past due and nonaccrual [Line Items]
Loans	29,000	0
Nonperforming [Member] | Other consumer [Member]
Past due and nonaccrual [Line Items]
Loans	8,000	64,000
Nonperforming [Member] | Commercial business [Member]
Past due and nonaccrual [Line Items]
Loans	197,000	0
With a related allowance recorded [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	1,018,000	1,254,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	7,392,000	6,969,000
Interest income recognized	244,000	153,000
With a related allowance recorded [Member] | One-to four- family [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	392,000	541,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	4,902,000	3,819,000
Interest income recognized	142,000	110,000
With a related allowance recorded [Member] | Home equity [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	247,000	447,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	1,117,000	864,000
Interest income recognized	35,000	11,000
With a related allowance recorded [Member] | Commercial and multifamily [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	70,000	38,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	290,000	1,847,000
Interest income recognized	9,000	6,000
With a related allowance recorded [Member] | Construction and land [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	25,000	37,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	119,000	112,000
Interest income recognized	4,000	8,000
With a related allowance recorded [Member] | Manufactured homes [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	117,000	11,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	670,000	97,000
Interest income recognized	43,000	13,000
With a related allowance recorded [Member] | Other consumer [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	22,000	48,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	91,000	52,000
Interest income recognized	3,000	2,000
With a related allowance recorded [Member] | Commercial business [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	145,000	132,000
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	203,000	178,000
Interest income recognized	8,000	3,000
With no related allowance recorded [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	6,714,000	4,546,000
Interest income recognized	280,000	144,000
With no related allowance recorded [Member] | One-to four- family [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	2,549,000	2,338,000
Interest income recognized	124,000	80,000
With no related allowance recorded [Member] | Home equity [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	792,000	641,000
Interest income recognized	39,000	17,000
With no related allowance recorded [Member] | Commercial and multifamily [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	1,898,000	1,151,000
Interest income recognized	81,000	3,000
With no related allowance recorded [Member] | Construction and land [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	592,000	195,000
Interest income recognized	19,000	39,000
With no related allowance recorded [Member] | Manufactured homes [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	70,000	42,000
Interest income recognized	5,000	0
With no related allowance recorded [Member] | Other consumer [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	13,000	44,000
Interest income recognized	2,000	3,000
With no related allowance recorded [Member] | Commercial business [Member]
Impaired Financing Receivable, Recorded Investment [Abstract]
Related allowance	0	0
Impaired Loans, Average Recorded Investment [Abstract]
Average recorded investment	800,000	135,000
Interest income recognized	$ 10,000	$ 2,000