Loans Receivable, Net - Summary of Loans Individually Evaluated for Impairment by Loan Portfolio Segment (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 43,558,000		$ 43,558,000		$ 36,979,000
Allowance for Loan Losses Allocated	2,106,000		2,106,000		2,161,000
With No Related Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	33,201,000		33,201,000		27,482,000
Recorded Investment	32,218,000		32,218,000		26,487,000
Average Recorded Investment	31,868,000	$ 28,170,000	29,311,000	$ 27,572,000
Interest Income Recognized	271,000	212,000	522,000	433,000
With an Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	11,434,000		11,434,000		10,492,000
Recorded Investment	11,340,000		11,340,000		10,492,000
Allowance for Loan Losses Allocated	2,106,000		2,106,000		2,161,000
Average Recorded Investment	10,716,000	14,665,000	10,453,000	14,830,000
Interest Income Recognized	24,000	52,000	50,000	115,000
Residential Real Estate [Member] | With No Related Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	13,094,000		13,094,000		12,351,000
Recorded Investment	12,674,000		12,674,000		11,931,000
Average Recorded Investment	13,724,000	17,707,000	12,775,000	17,608,000
Interest Income Recognized	144,000	169,000	294,000	317,000
Residential Real Estate [Member] | With an Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	295,000		295,000		948,000
Recorded Investment	261,000		261,000		948,000
Allowance for Loan Losses Allocated	65,000		65,000		88,000
Average Recorded Investment	263,000	1,259,000	262,000	1,264,000
Interest Income Recognized	3,000	15,000	6,000	31,000
Commercial Real Estate [Member] | With No Related Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	16,591,000		16,591,000		12,174,000
Recorded Investment	16,513,000		16,513,000		12,142,000
Average Recorded Investment	15,182,000	8,046,000	13,626,000	7,526,000
Interest Income Recognized	97,000	20,000	169,000	70,000
Commercial Real Estate [Member] | With an Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	10,592,000		10,592,000		9,023,000
Recorded Investment	10,532,000		10,532,000		9,023,000
Allowance for Loan Losses Allocated	1,721,000		1,721,000		1,741,000
Average Recorded Investment	10,087,000	12,721,000	10,008,000	12,888,000
Interest Income Recognized	19,000	26,000	42,000	63,000
Consumer [Member] | With No Related Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,813,000		2,813,000		2,243,000
Recorded Investment	2,328,000		2,328,000		1,700,000
Average Recorded Investment	2,255,000	2,141,000	2,201,000	2,161,000
Interest Income Recognized	30,000	20,000	59,000	41,000
Consumer [Member] | With an Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance					521,000
Recorded Investment					521,000
Allowance for Loan Losses Allocated					332,000
Average Recorded Investment		685,000		678,000
Interest Income Recognized		11,000		21,000
Commercial and Industrial [Member] | With No Related Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	703,000		703,000		714,000
Recorded Investment	703,000		703,000		$ 714,000
Average Recorded Investment	707,000	276,000	709,000	277,000
Interest Income Recognized		$ 3,000		$ 5,000
Commercial and Industrial [Member] | With an Allowance Recorded [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	547,000		547,000
Recorded Investment	547,000		547,000
Allowance for Loan Losses Allocated	320,000		320,000
Average Recorded Investment	366,000		183,000
Interest Income Recognized	$ 2,000		$ 2,000