Delinquency Information for Loans Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
30-59 Days Past Due	$ 1,097	$ 2,457
60-89 Days Past Due	1,833	569
90 Days or More Past Due	4,131	2,816
Total Past Due	7,061	5,842
Current	18,944	18,580
Total	26,005	24,422
Residential real estate loans
Financing Receivable, Recorded Investment [Line Items]
30-59 Days Past Due	1,097	2,457
60-89 Days Past Due	1,833	569
90 Days or More Past Due	4,131	2,816
Total Past Due	7,061	5,842
Current	14,795	16,367
Total	21,856	22,209
Commercial real estate loans
Financing Receivable, Recorded Investment [Line Items]
30-59 Days Past Due
60-89 Days Past Due
90 Days or More Past Due
Total Past Due
Current	1,673	1,722
Total	1,673	1,722
Commercial loans
Financing Receivable, Recorded Investment [Line Items]
30-59 Days Past Due
60-89 Days Past Due
90 Days or More Past Due
Total Past Due
Current	2,476	491
Total	2,476	491
Commercial loans | Revolving lines of credit
Financing Receivable, Recorded Investment [Line Items]
30-59 Days Past Due
60-89 Days Past Due
90 Days or More Past Due
Total Past Due
Current	1,965
Total	1,965
Commercial loans | Term note
Financing Receivable, Recorded Investment [Line Items]
30-59 Days Past Due
60-89 Days Past Due
90 Days or More Past Due
Total Past Due
Current	511	491
Total	$ 511	$ 491