Acquisitions - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		1 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	May 31, 2013 Somerset Hills Bancorp [Member]	Sep. 30, 2013 Somerset Hills Bancorp [Member]
Business Acquisition, Contingent Consideration [Line Items]
Date of Agreement						May 31, 2013
Shares received by the Somerset Hills Bancorp at the time of merger					$ 1.1962
Cash received by the Somerset Hills Bancorp at the time of merger					$ 12.00
Percentage of aggregate merger consideration in shares					90.00%
Percentage of aggregate merger consideration in cash					10.00%
Common stock expected to issue					5,794,079
Transaction value					$ 6,500,000
Core deposit intangible	2,700,000		2,700,000
Estimated useful life of deposit intangible			10 years
Merger and acquisition integration-related expenses	$ 744,000		$ 2,827,000