Business Combination - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Business Acquisition [Line Items]
Goodwill, acquired during period		$ 1,300,000
Acquired finite-lived intangible assets, weighted average useful life		10 years
Business acquisition purchase price allocation loans receivable	124,200,000	124,200,000
Business combination fair value adjustments loans		5,000,000
Business combination, acquisition related costs	447,000	1,408,000
Core Deposits
Business Acquisition [Line Items]
Finite-lived intangible assets acquired		7,000,000
Alabama Corporation
Business Acquisition [Line Items]
Business acquisition costs of acquired entity purchase price	$ 3,300,000	$ 3,300,000