Fair Value - Financial Instruments Measured At Fair Value On a Non-Recurring Basis (Detail) (Financial instruments measured at fair value on a non-recurring basis [Member], USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Comparable sales approach [Member]
Impaired loans:
Valuation Technique(s)	Comparable sales approach
Multi-family residential [Member]
Impaired loans:
Commercial real estate at Fair Value	3,937
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(32.70%)
Multi-family residential [Member] | Comparable sales approach [Member]
Impaired loans:
Valuation Technique(s)	Comparable sales approach
Commercial Real Estate [Member]
Impaired loans:
Impaired loans at Fair Value	121
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	8.10%
Commercial Real Estate [Member] | Income approach [Member]
Impaired loans:
Valuation Technique(s)	Income approach
Commercial Real Estate [Member] | Non-owner occupied [Member]
Impaired loans:
Commercial real estate at Fair Value	1,839
Foreclosed assets, net	967
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	3.20%
Commercial Real Estate [Member] | Non-owner occupied [Member] | Comparable sales approach [Member]
Impaired loans:
Valuation Technique(s)	Comparable sales approach
Commercial Real Estate [Member] | Non-owner occupied [Member] | Market approach [Member]
Impaired loans:
Valuation Technique(s)	Market approach
Commercial Real Estate [Member] | Owner occupied [Member]
Impaired loans:
Commercial real estate at Fair Value	1,293
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(5.40%)
Commercial Real Estate [Member] | Owner occupied [Member] | Comparable sales approach [Member]
Impaired loans:
Valuation Technique(s)	Comparable sales approach
Commercial Real Estate [Member] | Land [Member]
Impaired loans:
Commercial real estate at Fair Value	159
Foreclosed assets, net	447
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(31.70%)
Commercial Real Estate [Member] | Land [Member] | Income approach [Member]
Impaired loans:
Valuation Technique(s)	Income approach
Commercial Real Estate [Member] | Land [Member] | Comparable sales approach [Member]
Impaired loans:
Valuation Technique(s)	Comparable sales approach
Minimum [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences in land contract cash flow expectations	(10.00%)
Minimum [Member] | Multi-family residential [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(39.00%)
Minimum [Member] | Commercial Real Estate [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	8.10%
Minimum [Member] | Commercial Real Estate [Member] | Non-owner occupied [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(9.70%)
Fair Value Inputs, by sales contracts	0.00%
Minimum [Member] | Commercial Real Estate [Member] | Owner occupied [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(6.30%)
Minimum [Member] | Commercial Real Estate [Member] | Land [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(31.70%)
Minimum [Member] | Real estate [Member] | Land [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences in land contract cash flow expectations	0.00%
Maximum [Member] | Multi-family residential [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	(27.10%)
Maximum [Member] | Commercial Real Estate [Member] | Non-owner occupied [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	16.70%
Maximum [Member] | Commercial Real Estate [Member] | Owner occupied [Member]
Impaired loans:
Fair Value Inputs,Adjustment for differences between the comparable market transactions	8.10%