Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	$ 2,213,000	$ 2,213,000
Total amortization expense for other intangible assets, including discontinued operations	379,000
Intangible asset impairment charges	0	0
Core deposit intangible [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	$ 2,213,000	$ 2,213,000